This converts some of the visually simpler cases that have been split
over multiple lines. I only did the ones that are easy to verify the
resulting diff by having just that final GFP_KERNEL argument on the next
line.
Somebody should probably do a proper coccinelle script for this, but for
me the trivial script actually resulted in an assertion failure in the
middle of the script. I probably had made it a bit _too_ trivial.
So after fighting that far a while I decided to just do some of the
syntactically simpler cases with variations of the previous 'sed'
scripts.
The more syntactically complex multi-line cases would mostly really want
whitespace cleanup anyway.
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
This is the exact same thing as the 'alloc_obj()' version, only much
smaller because there are a lot fewer users of the *alloc_flex()
interface.
As with alloc_obj() version, this was done entirely with mindless brute
force, using the same script, except using 'flex' in the pattern rather
than 'objs*'.
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
This was done entirely with mindless brute force, using
git grep -l '\<k[vmz]*alloc_objs*(.*, GFP_KERNEL)' |
xargs sed -i 's/\(alloc_objs*(.*\), GFP_KERNEL)/\1)/'
to convert the new alloc_obj() users that had a simple GFP_KERNEL
argument to just drop that argument.
Note that due to the extreme simplicity of the scripting, any slightly
more complex cases spread over multiple lines would not be triggered:
they definitely exist, but this covers the vast bulk of the cases, and
the resulting diff is also then easier to check automatically.
For the same reason the 'flex' versions will be done as a separate
conversion.
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
This is the result of running the Coccinelle script from
scripts/coccinelle/api/kmalloc_objs.cocci. The script is designed to
avoid scalar types (which need careful case-by-case checking), and
instead replace kmalloc-family calls that allocate struct or union
object instances:
Single allocations: kmalloc(sizeof(TYPE), ...)
are replaced with: kmalloc_obj(TYPE, ...)
Array allocations: kmalloc_array(COUNT, sizeof(TYPE), ...)
are replaced with: kmalloc_objs(TYPE, COUNT, ...)
Flex array allocations: kmalloc(struct_size(PTR, FAM, COUNT), ...)
are replaced with: kmalloc_flex(*PTR, FAM, COUNT, ...)
(where TYPE may also be *VAR)
The resulting allocations no longer return "void *", instead returning
"TYPE *".
Signed-off-by: Kees Cook <kees@kernel.org>
This field is now used only for linked scalar registers tracking.
Rename it to 'delta' to better describe it's purpose:
constant delta between "linked" scalars with the same ID.
Signed-off-by: Eduard Zingerman <eddyz87@gmail.com>
Link: https://lore.kernel.org/r/20260212-ptrs-off-migration-v2-4-00820e4d3438@gmail.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
This commit consolidates static and varying pointer offset tracking
logic. All offsets are now represented solely using `.var_off` and
min/max fields. The reasons are twofold:
- This simplifies pointer tracking code, as each relevant function
needs to check the `.var_off` field anyway.
- It makes it easier to widen pointer registers for the purpose of loop
convergence checks, by forgoing the `regsafe()` logic demanding
`.off` fields to be identical.
The changes are spread across many functions and are hard to group
into smaller patches. Some of the logical changes include:
- Checks in __check_ptr_off_reg() are reordered so that the
tnum_is_const() check is done before operating on reg->var_off.value.
- check_packet_access() now uses check_mem_region_access() to handle
possible 'off' overflow cases.
- In check_helper_mem_access() utility functions like
check_packet_access() are now called with 'off=0', as these utility
functions now account for the complete register offset range.
- In check_reg_type() a call to __check_ptr_off_reg() is added before
a call to btf_struct_ids_match(). This prevents
btf_struct_ids_match() from potentially working on non-constant
reg->var_off.value.
- regsafe() is relaxed to avoid comparing '.off' field for pointers.
As a precaution, the changes are verified in [1] by adding a pass
checking that no pointer has non-zero '.off' field on each
do_check_insn() iteration.
[1] https://github.com/eddyz87/bpf/tree/ptrs-off-migration
Notable selftests changes:
- `.var_off` value changed because it now combines static and varying
offsets. Affected tests:
- linked_list/incorrect_node_var_off
- linked_list/incorrect_head_var_off2
- verifier_align/packet_variable_offset
- Overflowing `smax_value` bound leads to a pointer with big negative
or positive offset to be rejected immediately (previously overflowing
`rX += const` instruction updated `.off` field avoiding the overflow).
Affected tests:
- verifier_align/dubious_pointer_arithmetic
- verifier_bounds/var_off_insn_off_test1
- Invalid access to packet now reports full offset inside a packet.
Affected tests:
- verifier_direct_packet_access/test23_x_pkt_ptr_4
- A change in check_mem_region_access() behavior:
when register `.smin_value` is negative, it reports
"rX min value is negative..." before calling into __check_mem_access()
which reports "invalid access to ...".
In the tests below, the `.off` field was negative, while `.smin_value`
remained positive. This is no longer the case after the changes in
this commit. Affected tests:
- verifier_gotox/jump_table_invalid_mem_acceess_neg
- verifier_helper_packet_access/test15_cls_helper_fail_sub
- verifier_helper_value_access/imm_out_of_bound_2
- verifier_helper_value_access/reg_out_of_bound_2
- verifier_meta_access/meta_access_test2
- verifier_value_ptr_arith/known_scalar_from_different_maps
- lower_oob_arith_test_1
- value_ptr_known_scalar_3
- access_value_ptr_known_scalar
- Usage of check_mem_region_access() instead of __check_mem_access()
in check_packet_access() changes the reported message from
"rX offset is outside ..." to "rX min/max value is outside ...".
Affected tests:
- verifier_xdp_direct_packet_access/*
- In check_func_arg_reg_off() the check for zero offset now operates
on `.var_off` field instead of `.off` field. For tests where the
pattern looks like `kfunc(reg_with_var_off, ...)`, this changes the
reported error:
- previously the error "variable ... access ... disallowed"
was reported by __check_ptr_off_reg();
- now "R1 must have zero offset ..." is reported by
check_func_arg_reg_off() itself.
Affected tests:
- verifier/calls.c
"calls: invalid kfunc call: PTR_TO_BTF_ID with variable offset"
Signed-off-by: Eduard Zingerman <eddyz87@gmail.com>
Link: https://lore.kernel.org/r/20260212-ptrs-off-migration-v2-2-00820e4d3438@gmail.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
check_reg_sane_offset() is used when verifying operations like:
dst_reg += src_reg
^ ^
| '-------- scalar
'------------------- pointer
To verify range for both dst_reg and src_reg. Split it in two parts:
- one to check a pointer offset
- another to check scalar offset
This would be useful for further refactoring.
Signed-off-by: Eduard Zingerman <eddyz87@gmail.com>
Link: https://lore.kernel.org/r/20260212-ptrs-off-migration-v2-1-00820e4d3438@gmail.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
The add_fd_from_fd_array() function takes a file descriptor as a
parameter and tries to add either map or btf to the corresponding
list of used objects. As was reported by Dan Carpenter, since the
commit c81e4322acf0 ("bpf: Fix a potential use-after-free of BTF
object"), the fdget() is called twice on the file descriptor, and
thus userspace, potentially, can replace the file pointed to by the
file descriptor in between the two calls. On practice, this shouldn't
break anything on the kernel side, but for consistency fix the code
such that only one fdget() is executed.
Reported-by: Dan Carpenter <dan.carpenter@linaro.org>
Closes: https://lore.kernel.org/r/aY689z7gHNv8rgVO@stanley.mountain/
Fixes: ccd2d799ed ("bpf: Fix a potential use-after-free of BTF object")
Signed-off-by: Anton Protopopov <a.s.protopopov@gmail.com>
Link: https://lore.kernel.org/r/20260213212949.759321-1-a.s.protopopov@gmail.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Total patches: 107
Reviews/patch: 1.07
Reviewed rate: 67%
- The 2 patch series "ocfs2: give ocfs2 the ability to reclaim
suballocator free bg" from Heming Zhao saves disk space by teaching
ocfs2 to reclaim suballocator block group space.
- The 4 patch series "Add ARRAY_END(), and use it to fix off-by-one
bugs" from Alejandro Colomar adds the ARRAY_END() macro and uses it in
various places.
- The 2 patch series "vmcoreinfo: support VMCOREINFO_BYTES larger than
PAGE_SIZE" from Pnina Feder makes the vmcore code future-safe, if
VMCOREINFO_BYTES ever exceeds the page size.
- The 7 patch series "kallsyms: Prevent invalid access when showing
module buildid" from Petr Mladek cleans up kallsyms code related to
module buildid and fixes an invalid access crash when printing
backtraces.
- The 3 patch series "Address page fault in
ima_restore_measurement_list()" from Harshit Mogalapalli fixes a
kexec-related crash that can occur when booting the second-stage kernel
on x86.
- The 6 patch series "kho: ABI headers and Documentation updates" from
Mike Rapoport updates the kexec handover ABI documentation.
- The 4 patch series "Align atomic storage" from Finn Thain adds the
__aligned attribute to atomic_t and atomic64_t definitions to get
natural alignment of both types on csky, m68k, microblaze, nios2,
openrisc and sh.
- The 2 patch series "kho: clean up page initialization logic" from
Pratyush Yadav simplifies the page initialization logic in
kho_restore_page().
- The 6 patch series "Unload linux/kernel.h" from Yury Norov moves
several things out of kernel.h and into more appropriate places.
- The 7 patch series "don't abuse task_struct.group_leader" from Oleg
Nesterov removes the usage of ->group_leader when it is "obviously
unnecessary".
- The 5 patch series "list private v2 & luo flb" from Pasha Tatashin
adds some infrastructure improvements to the live update orchestrator.
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Merge tag 'mm-nonmm-stable-2026-02-12-10-48' of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm
Pull non-MM updates from Andrew Morton:
- "ocfs2: give ocfs2 the ability to reclaim suballocator free bg" saves
disk space by teaching ocfs2 to reclaim suballocator block group
space (Heming Zhao)
- "Add ARRAY_END(), and use it to fix off-by-one bugs" adds the
ARRAY_END() macro and uses it in various places (Alejandro Colomar)
- "vmcoreinfo: support VMCOREINFO_BYTES larger than PAGE_SIZE" makes
the vmcore code future-safe, if VMCOREINFO_BYTES ever exceeds the
page size (Pnina Feder)
- "kallsyms: Prevent invalid access when showing module buildid" cleans
up kallsyms code related to module buildid and fixes an invalid
access crash when printing backtraces (Petr Mladek)
- "Address page fault in ima_restore_measurement_list()" fixes a
kexec-related crash that can occur when booting the second-stage
kernel on x86 (Harshit Mogalapalli)
- "kho: ABI headers and Documentation updates" updates the kexec
handover ABI documentation (Mike Rapoport)
- "Align atomic storage" adds the __aligned attribute to atomic_t and
atomic64_t definitions to get natural alignment of both types on
csky, m68k, microblaze, nios2, openrisc and sh (Finn Thain)
- "kho: clean up page initialization logic" simplifies the page
initialization logic in kho_restore_page() (Pratyush Yadav)
- "Unload linux/kernel.h" moves several things out of kernel.h and into
more appropriate places (Yury Norov)
- "don't abuse task_struct.group_leader" removes the usage of
->group_leader when it is "obviously unnecessary" (Oleg Nesterov)
- "list private v2 & luo flb" adds some infrastructure improvements to
the live update orchestrator (Pasha Tatashin)
* tag 'mm-nonmm-stable-2026-02-12-10-48' of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm: (107 commits)
watchdog/hardlockup: simplify perf event probe and remove per-cpu dependency
procfs: fix missing RCU protection when reading real_parent in do_task_stat()
watchdog/softlockup: fix sample ring index wrap in need_counting_irqs()
kcsan, compiler_types: avoid duplicate type issues in BPF Type Format
kho: fix doc for kho_restore_pages()
tests/liveupdate: add in-kernel liveupdate test
liveupdate: luo_flb: introduce File-Lifecycle-Bound global state
liveupdate: luo_file: Use private list
list: add kunit test for private list primitives
list: add primitives for private list manipulations
delayacct: fix uapi timespec64 definition
panic: add panic_force_cpu= parameter to redirect panic to a specific CPU
netclassid: use thread_group_leader(p) in update_classid_task()
RDMA/umem: don't abuse current->group_leader
drm/pan*: don't abuse current->group_leader
drm/amd: kill the outdated "Only the pthreads threading model is supported" checks
drm/amdgpu: don't abuse current->group_leader
android/binder: use same_thread_group(proc->tsk, current) in binder_mmap()
android/binder: don't abuse current->group_leader
kho: skip memoryless NUMA nodes when reserving scratch areas
...
Take care of rqspinlock error in bpf_local_storage_{map_free, destroy}()
properly by switching to bpf_selem_unlink_nofail().
Both functions iterate their own RCU-protected list of selems and call
bpf_selem_unlink_nofail(). In map_free(), to prevent infinite loop when
both map_free() and destroy() fail to remove a selem from b->list
(extremely unlikely), switch to hlist_for_each_entry_rcu(). In destroy(),
also switch to hlist_for_each_entry_rcu() since we no longer iterate
local_storage->list under local_storage->lock.
bpf_selem_unlink() now becomes dedicated to helpers and syscalls paths
so reuse_now should always be false. Remove it from the argument and
hardcode it.
Acked-by: Alexei Starovoitov <ast@kernel.org>
Co-developed-by: Martin KaFai Lau <martin.lau@kernel.org>
Signed-off-by: Amery Hung <ameryhung@gmail.com>
Signed-off-by: Martin KaFai Lau <martin.lau@kernel.org>
Link: https://patch.msgid.link/20260205222916.1788211-12-ameryhung@gmail.com
Introduce bpf_selem_unlink_nofail() to properly handle errors returned
from rqspinlock in bpf_local_storage_map_free() and
bpf_local_storage_destroy() where the operation must succeeds.
The idea of bpf_selem_unlink_nofail() is to allow an selem to be
partially linked and use atomic operation on a bit field, selem->state,
to determine when and who can free the selem if any unlink under lock
fails. An selem initially is fully linked to a map and a local storage.
Under normal circumstances, bpf_selem_unlink_nofail() will be able to
grab locks and unlink a selem from map and local storage in sequeunce,
just like bpf_selem_unlink(), and then free it after an RCU grace period.
However, if any of the lock attempts fails, it will only clear
SDATA(selem)->smap or selem->local_storage depending on the caller and
set SELEM_MAP_UNLINKED or SELEM_STORAGE_UNLINKED according to the
caller. Then, after both map_free() and destroy() see the selem and the
state becomes SELEM_UNLINKED, one of two racing caller can succeed in
cmpxchg the state from SELEM_UNLINKED to SELEM_TOFREE, ensuring no
double free or memory leak.
To make sure bpf_obj_free_fields() is done only once and when map is
still present, it is called when unlinking an selem from b->list under
b->lock.
To make sure uncharging memory is done only when the owner is still
present in map_free(), block destroy() from returning until there is no
pending map_free().
Since smap may not be valid in destroy(), bpf_selem_unlink_nofail()
skips bpf_selem_unlink_storage_nolock_misc() when called from destroy().
This is okay as bpf_local_storage_destroy() will return the remaining
amount of memory charge tracked by mem_charge to the owner to uncharge.
It is also safe to skip clearing local_storage->owner and owner_storage
as the owner is being freed and no users or bpf programs should be able
to reference the owner and using local_storage.
Finally, access of selem, SDATA(selem)->smap and selem->local_storage
are racy. Callers will protect these fields with RCU.
Acked-by: Alexei Starovoitov <ast@kernel.org>
Co-developed-by: Martin KaFai Lau <martin.lau@kernel.org>
Signed-off-by: Amery Hung <ameryhung@gmail.com>
Signed-off-by: Martin KaFai Lau <martin.lau@kernel.org>
Link: https://patch.msgid.link/20260205222916.1788211-11-ameryhung@gmail.com
The next patch will introduce bpf_selem_unlink_nofail() to handle
rqspinlock errors. bpf_selem_unlink_nofail() will allow an selem to be
partially unlinked from map or local storage. Save memory allocation
method in selem so that later an selem can be correctly freed even when
SDATA(selem)->smap is init to NULL.
In addition, keep track of memory charge to the owner in local storage
so that later bpf_selem_unlink_nofail() can return the correct memory
charge to the owner. Updating local_storage->mem_charge is protected by
local_storage->lock.
Finally, extract miscellaneous tasks performed when unlinking an selem
from local_storage into bpf_selem_unlink_storage_nolock_misc(). It will
be reused by bpf_selem_unlink_nofail().
This patch also takes the chance to remove local_storage->smap, which
is no longer used since commit f484f4a3e0 ("bpf: Replace bpf memory
allocator with kmalloc_nolock() in local storage").
Acked-by: Alexei Starovoitov <ast@kernel.org>
Signed-off-by: Amery Hung <ameryhung@gmail.com>
Signed-off-by: Martin KaFai Lau <martin.lau@kernel.org>
Link: https://patch.msgid.link/20260205222916.1788211-10-ameryhung@gmail.com
Percpu locks have been removed from cgroup and task local storage. Now
that all local storage no longer use percpu variables as locks preventing
recursion, there is no need to pass them to bpf_local_storage_map_free().
Remove the argument from the function.
Acked-by: Alexei Starovoitov <ast@kernel.org>
Signed-off-by: Amery Hung <ameryhung@gmail.com>
Signed-off-by: Martin KaFai Lau <martin.lau@kernel.org>
Link: https://patch.msgid.link/20260205222916.1788211-9-ameryhung@gmail.com
The percpu counter in cgroup local storage is no longer needed as the
underlying bpf_local_storage can now handle deadlock with the help of
rqspinlock. Remove the percpu counter and related migrate_{disable,
enable}.
Acked-by: Alexei Starovoitov <ast@kernel.org>
Signed-off-by: Amery Hung <ameryhung@gmail.com>
Signed-off-by: Martin KaFai Lau <martin.lau@kernel.org>
Link: https://patch.msgid.link/20260205222916.1788211-8-ameryhung@gmail.com
The percpu counter in task local storage is no longer needed as the
underlying bpf_local_storage can now handle deadlock with the help of
rqspinlock. Remove the percpu counter and related migrate_{disable,
enable}.
Since the percpu counter is removed, merge back bpf_task_storage_get()
and bpf_task_storage_get_recur(). This will allow the bpf syscalls and
helpers to run concurrently on the same CPU, removing the spurious
-EBUSY error. bpf_task_storage_get(..., F_CREATE) will now always
succeed with enough free memory unless being called recursively.
Acked-by: Alexei Starovoitov <ast@kernel.org>
Signed-off-by: Amery Hung <ameryhung@gmail.com>
Signed-off-by: Martin KaFai Lau <martin.lau@kernel.org>
Link: https://patch.msgid.link/20260205222916.1788211-7-ameryhung@gmail.com
Change bpf_local_storage::lock and bpf_local_storage_map_bucket::lock
from raw_spin_lock to rqspinlock.
Finally, propagate errors from raw_res_spin_lock_irqsave() to syscall
return or BPF helper return.
In bpf_local_storage_destroy(), ignore return from
raw_res_spin_lock_irqsave() for now. A later patch will correctly
handle errors correctly in bpf_local_storage_destroy() so that it can
unlink selems even when failing to acquire locks.
For __bpf_local_storage_map_cache(), instead of handling the error,
skip updating the cache.
Acked-by: Alexei Starovoitov <ast@kernel.org>
Signed-off-by: Amery Hung <ameryhung@gmail.com>
Signed-off-by: Martin KaFai Lau <martin.lau@kernel.org>
Link: https://patch.msgid.link/20260205222916.1788211-6-ameryhung@gmail.com
To prepare changing both bpf_local_storage_map_bucket::lock and
bpf_local_storage::lock to rqspinlock, convert bpf_selem_unlink() to
failable. It still always succeeds and returns 0 until the change
happens. No functional change.
Open code bpf_selem_unlink_storage() in the only caller,
bpf_selem_unlink(), since unlink_map and unlink_storage must be done
together after all the necessary locks are acquired.
For bpf_local_storage_map_free(), ignore the return from
bpf_selem_unlink() for now. A later patch will allow it to unlink selems
even when failing to acquire locks.
Acked-by: Alexei Starovoitov <ast@kernel.org>
Signed-off-by: Amery Hung <ameryhung@gmail.com>
Signed-off-by: Martin KaFai Lau <martin.lau@kernel.org>
Link: https://patch.msgid.link/20260205222916.1788211-5-ameryhung@gmail.com
To prepare for changing bpf_local_storage_map_bucket::lock to rqspinlock,
convert bpf_selem_link_map() to failable. It still always succeeds and
returns 0 until the change happens. No functional change.
Acked-by: Alexei Starovoitov <ast@kernel.org>
Signed-off-by: Amery Hung <ameryhung@gmail.com>
Signed-off-by: Martin KaFai Lau <martin.lau@kernel.org>
Link: https://patch.msgid.link/20260205222916.1788211-4-ameryhung@gmail.com
To prepare for changing bpf_local_storage_map_bucket::lock to rqspinlock,
convert bpf_selem_unlink_map() to failable. It still always succeeds and
returns 0 for now.
Since some operations updating local storage cannot fail in the middle,
open-code bpf_selem_unlink_map() to take the b->lock before the
operation. There are two such locations:
- bpf_local_storage_alloc()
The first selem will be unlinked from smap if cmpxchg owner_storage_ptr
fails, which should not fail. Therefore, hold b->lock when linking
until allocation complete. Helpers that assume b->lock is held by
callers are introduced: bpf_selem_link_map_nolock() and
bpf_selem_unlink_map_nolock().
- bpf_local_storage_update()
The three step update process: link_map(new_selem),
link_storage(new_selem), and unlink_map(old_selem) should not fail in
the middle.
In bpf_selem_unlink(), bpf_selem_unlink_map() and
bpf_selem_unlink_storage() should either all succeed or fail as a whole
instead of failing in the middle. So, return if unlink_map() failed.
Remove the selem_linked_to_map_lockless() check as an selem in the
common paths (not bpf_local_storage_map_free() or
bpf_local_storage_destroy()), will be unlinked under b->lock and
local_storage->lock and therefore no other threads can unlink the selem
from map at the same time.
In bpf_local_storage_destroy(), ignore the return of
bpf_selem_unlink_map() for now. A later patch will allow
bpf_local_storage_destroy() to unlink selems even when failing to
acquire locks.
Note that while this patch removes all callers of selem_linked_to_map(),
a later patch that introduces bpf_selem_unlink_nofail() will use it
again.
Acked-by: Alexei Starovoitov <ast@kernel.org>
Signed-off-by: Amery Hung <ameryhung@gmail.com>
Signed-off-by: Martin KaFai Lau <martin.lau@kernel.org>
Link: https://patch.msgid.link/20260205222916.1788211-3-ameryhung@gmail.com
A later bpf_local_storage refactor will acquire all locks before
performing any update. To simplified the number of locks needed to take
in bpf_local_storage_map_update(), determine the bucket based on the
local_storage an selem belongs to instead of the selem pointer.
Currently, when a new selem needs to be created to replace the old selem
in bpf_local_storage_map_update(), locks of both buckets need to be
acquired to prevent racing. This can be simplified if the two selem
belongs to the same bucket so that only one bucket needs to be locked.
Therefore, instead of hashing selem, hashing the local_storage pointer
the selem belongs.
Performance wise, this is slightly better as update now requires locking
one bucket. It should not change the level of contention on one bucket
as the pointers to local storages of selems in a map are just as unique
as pointers to selems.
Acked-by: Alexei Starovoitov <ast@kernel.org>
Signed-off-by: Amery Hung <ameryhung@gmail.com>
Signed-off-by: Martin KaFai Lau <martin.lau@kernel.org>
Link: https://patch.msgid.link/20260205222916.1788211-2-ameryhung@gmail.com
call_rcu_tasks_trace() is not safe from in_nmi() and not reentrant.
To prevent deadlock on raw_spin_lock_rcu_node(rtpcp) or memory corruption
defer to irq_work when IRQs are disabled. call_rcu_tasks_generic()
protects itself with local_irq_save().
Note when bpf_async_cb->refcnt drops to zero it's safe to reuse
bpf_async_cb->worker for a different irq_work callback, since
bpf_async_schedule_op() -> irq_work_queue(&cb->worker);
is only called when refcnt >= 1.
Fixes: 1bfbc267ec ("bpf: Enable bpf_timer and bpf_wq in any context")
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Link: https://lore.kernel.org/bpf/20260205190233.912-1-alexei.starovoitov@gmail.com
Currently, bpf_map_get_info_by_fd calculates and caches the hash of the
map regardless of the map's frozen state.
This leads to a TOCTOU bug where userspace can call
BPF_OBJ_GET_INFO_BY_FD to cache the hash and then modify the map
contents before freezing.
Therefore, a trusted loader can be tricked into verifying the stale hash
while loading the modified contents.
Fix this by returning -EPERM if the map is not frozen when the hash is
requested. This ensures the hash is only generated for the final,
immutable state of the map.
Fixes: ea2e6467ac ("bpf: Return hashes of maps in BPF_OBJ_GET_INFO_BY_FD")
Reported-by: Toshi Piazza <toshi.piazza@microsoft.com>
Signed-off-by: KP Singh <kpsingh@kernel.org>
Acked-by: Daniel Borkmann <daniel@iogearbox.net>
Link: https://lore.kernel.org/r/20260205070755.695776-1-kpsingh@kernel.org
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Practical BPF signatures are significantly smaller than
KMALLOC_MAX_CACHE_SIZE
Allowing larger sizes opens the door for abuse by passing excessive
size values and forcing the kernel into expensive allocation paths (via
kmalloc_large or vmalloc).
Fixes: 3492715683 ("bpf: Implement signature verification for BPF programs")
Reported-by: Chris Mason <clm@meta.com>
Signed-off-by: KP Singh <kpsingh@kernel.org>
Acked-by: Daniel Borkmann <daniel@iogearbox.net>
Link: https://lore.kernel.org/r/20260205063807.690823-1-kpsingh@kernel.org
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Replace prog and callback in bpf_async_cb after removing visibility of
bpf_async_cb in bpf_async_cancel_and_free() to increase the chances the
scheduled async callbacks short-circuit execution and exit early, and
not starting a RCU tasks trace section. This improves the overall time
spent in running the wq selftest.
Suggested-by: Alexei Starovoitov <ast@kernel.org>
Signed-off-by: Kumar Kartikeya Dwivedi <memxor@gmail.com>
Link: https://lore.kernel.org/r/20260205003853.527571-3-memxor@gmail.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
When freeing a bpf_async_cb in bpf_async_cb_rcu_tasks_trace_free(), in
case the wq callback is not scheduled, doing cancel_work() currently
returns false and leads to retry of RCU tasks trace grace period. If the
callback is never scheduled, we keep retrying indefinitely and don't put
the prog reference.
Since the only race we care about here is against a potentially running
wq callback in the first grace period, it should finish by the second
grace period, hence check work_busy() result to detect presence of
running wq callback if it's not pending, otherwise free the object
immediately without retrying.
Reasoning behind the check and its correctness with racing wq callback
invocation: cancel_work is supposed to be synchronized, hence calling it
first and getting false would mean that work is definitely not pending,
at this point, either the work is not scheduled at all or already
running, or we race and it already finished by the time we checked for
it using work_busy(). In case it is running, we synchronize using
pool->lock to check the current work running there, if we match, it
means we extend the wait by another grace period using retry = true,
otherwise either the work already finished running or was never
scheduled, so we can free the bpf_async_cb right away.
Fixes: 1bfbc267ec ("bpf: Enable bpf_timer and bpf_wq in any context")
Reported-by: Alexei Starovoitov <ast@kernel.org>
Signed-off-by: Kumar Kartikeya Dwivedi <memxor@gmail.com>
Link: https://lore.kernel.org/r/20260205003853.527571-2-memxor@gmail.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Previously, the verifier only tracked positive constant deltas between
linked registers using BPF_ADD. This limitation meant patterns like:
r1 = r0;
r1 += -4;
if r1 s>= 0 goto l0_%=; // r1 >= 0 implies r0 >= 4
// verifier couldn't propagate bounds back to r0
if r0 != 0 goto l0_%=;
r0 /= 0; // Verifier thinks this is reachable
l0_%=:
Similar limitation exists for 32-bit registers.
With this change, the verifier can now track negative deltas in reg->off
enabling bound propagation for the above pattern.
For alu32, we make sure the destination register has the upper 32 bits
as 0s before creating the link. BPF_ADD_CONST is split into
BPF_ADD_CONST64 and BPF_ADD_CONST32, the latter is used in case of alu32
and sync_linked_regs uses this to zext the result if known_reg has this
flag.
Signed-off-by: Puranjay Mohan <puranjay@kernel.org>
Acked-by: Eduard Zingerman <eddyz87@gmail.com>
Link: https://lore.kernel.org/r/20260204151741.2678118-2-puranjay@kernel.org
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
This patch implements bitwise tracking (tnum analysis) for BPF_END
(byte swap) operation.
Currently, the BPF verifier does not track value for BPF_END operation,
treating the result as completely unknown. This limits the verifier's
ability to prove safety of programs that perform endianness conversions,
which are common in networking code.
For example, the following code pattern for port number validation:
int test(struct pt_regs *ctx) {
__u64 x = bpf_get_prandom_u32();
x &= 0x3f00; // Range: [0, 0x3f00], var_off: (0x0; 0x3f00)
x = bswap16(x); // Should swap to range [0, 0x3f], var_off: (0x0; 0x3f)
if (x > 0x3f) goto trap;
return 0;
trap:
return *(u64 *)NULL; // Should be unreachable
}
Currently generates verifier output:
1: (54) w0 &= 16128 ; R0=scalar(smin=smin32=0,smax=umax=smax32=umax32=16128,var_off=(0x0; 0x3f00))
2: (d7) r0 = bswap16 r0 ; R0=scalar()
3: (25) if r0 > 0x3f goto pc+2 ; R0=scalar(smin=smin32=0,smax=umax=smax32=umax32=63,var_off=(0x0; 0x3f))
Without this patch, even though the verifier knows `x` has certain bits
set, after bswap16, it loses all tracking information and treats port
as having a completely unknown value [0, 65535].
According to the BPF instruction set[1], there are 3 kinds of BPF_END:
1. `bswap(16|32|64)`: opcode=0xd7 (BPF_END | BPF_ALU64 | BPF_TO_LE)
- do unconditional swap
2. `le(16|32|64)`: opcode=0xd4 (BPF_END | BPF_ALU | BPF_TO_LE)
- on big-endian: do swap
- on little-endian: truncation (16/32-bit) or no-op (64-bit)
3. `be(16|32|64)`: opcode=0xdc (BPF_END | BPF_ALU | BPF_TO_BE)
- on little-endian: do swap
- on big-endian: truncation (16/32-bit) or no-op (64-bit)
Since BPF_END operations are inherently bit-wise permutations, tnum
(bitwise tracking) offers the most efficient and precise mechanism
for value analysis. By implementing `tnum_bswap16`, `tnum_bswap32`,
and `tnum_bswap64`, we can derive exact `var_off` values concisely,
directly reflecting the bit-level changes.
Here is the overview of changes:
1. In `tnum_bswap(16|32|64)` (kernel/bpf/tnum.c):
Call `swab(16|32|64)` function on the value and mask of `var_off`, and
do truncation for 16/32-bit cases.
2. In `adjust_scalar_min_max_vals` (kernel/bpf/verifier.c):
Call helper function `scalar_byte_swap`.
- Only do byte swap when
* alu64 (unconditional swap) OR
* switching between big-endian and little-endian machines.
- If need do byte swap:
* Firstly call `tnum_bswap(16|32|64)` to update `var_off`.
* Then reset the bound since byte swap scrambles the range.
- For 16/32-bit cases, truncate dst register to match the swapped size.
This enables better verification of networking code that frequently uses
byte swaps for protocol processing, reducing false positive rejections.
[1] https://www.kernel.org/doc/Documentation/bpf/standardization/instruction-set.rst
Co-developed-by: Shenghao Yuan <shenghaoyuan0928@163.com>
Signed-off-by: Shenghao Yuan <shenghaoyuan0928@163.com>
Co-developed-by: Yazhou Tang <tangyazhou518@outlook.com>
Signed-off-by: Yazhou Tang <tangyazhou518@outlook.com>
Signed-off-by: Tianci Cao <ziye@zju.edu.cn>
Acked-by: Eduard Zingerman <eddyz87@gmail.com>
Link: https://lore.kernel.org/r/20260204111503.77871-2-ziye@zju.edu.cn
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Do not schedule timer/wq operation on a cpu that is in irq_work
callback that is processing async_cmds queue.
Otherwise the following loop is possible:
bpf_timer_start() -> bpf_async_schedule_op() -> irq_work_queue().
irqrestore -> bpf_async_irq_worker() -> tracepoint -> bpf_timer_start().
Fixes: 1bfbc267ec ("bpf: Enable bpf_timer and bpf_wq in any context")
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Link: https://lore.kernel.org/bpf/20260204055147.54960-4-alexei.starovoitov@gmail.com
Though hrtimer_start/cancel() inlines all of the smaller helpers in
hrtimer.c and only call timerqueue_add/del() from lib/timerqueue.c where
everything is not traceable and not kprobe-able (because all files in
lib/ are not traceable), there are tracepoints within hrtimer that are
called with locks held. Therefore prevent the deadlock by tightening
conditions when timer/wq can be called synchronously.
hrtimer/wq are using raw_spin_lock_irqsave(), so irqs_disabled() is enough.
Fixes: 1bfbc267ec ("bpf: Enable bpf_timer and bpf_wq in any context")
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Link: https://lore.kernel.org/bpf/20260204055147.54960-2-alexei.starovoitov@gmail.com
sk->sk_family should be read with READ_ONCE() in
__cgroup_bpf_run_filter_sock_addr() due to IPV6_ADDRFORM.
Also, the comment there is a bit stale since commit 859051dd16
("bpf: Implement cgroup sockaddr hooks for unix sockets"), and the
kdoc has the same comment.
Let's use sk_is_inet() and sk_is_unix() and remove the comment.
Acked-by: Stanislav Fomichev <sdf@fomichev.me>
Signed-off-by: Kuniyuki Iwashima <kuniyu@google.com>
Signed-off-by: Martin KaFai Lau <martin.lau@kernel.org>
Link: https://patch.msgid.link/20260203213442.682838-2-kuniyu@google.com
Extend the verifier to recognize struct bpf_timer as a valid kfunc
argument type. Previously, bpf_timer was only supported in BPF helpers.
This prepares for adding timer-related kfuncs in subsequent patches.
Signed-off-by: Mykyta Yatsenko <yatsenko@meta.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Acked-by: Andrii Nakryiko <andrii@kernel.org>
Link: https://lore.kernel.org/bpf/20260201025403.66625-3-alexei.starovoitov@gmail.com
Refactor bpf_timer and bpf_wq to allow calling them from any context:
- add refcnt to bpf_async_cb
- map_delete_elem or map_free will drop refcnt to zero
via bpf_async_cancel_and_free()
- once refcnt is zero timer/wq_start is not allowed to make sure
that callback cannot rearm itself
- if in_hardirq defer to start/cancel operations to irq_work
Co-developed-by: Mykyta Yatsenko <yatsenko@meta.com>
Signed-off-by: Mykyta Yatsenko <yatsenko@meta.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Acked-by: Kumar Kartikeya Dwivedi <memxor@gmail.com>
Link: https://lore.kernel.org/bpf/20260201025403.66625-2-alexei.starovoitov@gmail.com
The BPF stream kfuncs bpf_stream_vprintk and bpf_stream_print_stack
do not sleep and so are safe to call while holding a lock. Amend
the verifier to allow that.
Signed-off-by: Emil Tsalapatis <emil@etsalapatis.com>
Acked-by: Kumar Kartikeya Dwivedi <memxor@gmail.com>
Link: https://lore.kernel.org/r/20260203180424.14057-4-emil@etsalapatis.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Add a new kfunc called bpf_stream_print_stack to be used by programs
that need to print out their current BPF stack. The kfunc is essentially
a wrapper around the existing bpf_stream_dump_stack functionality used
to generate stack traces for error events like may_goto violations and
BPF-side arena page faults.
Signed-off-by: Emil Tsalapatis <emil@etsalapatis.com>
Acked-by: Kumar Kartikeya Dwivedi <memxor@gmail.com>
Link: https://lore.kernel.org/r/20260203180424.14057-2-emil@etsalapatis.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Scalar register IDs are used by the verifier to track relationships
between registers and enable bounds propagation across those
relationships. Once an ID becomes singular (i.e. only a single
register/stack slot carries it), it can no longer contribute to bounds
propagation and effectively becomes stale. The previous commit makes the
verifier clear such ids before caching the state.
When comparing the current and cached states for pruning, these stale
IDs can cause technically equivalent states to be considered different
and thus prevent pruning.
For example, in the selftest added in the next commit, two registers -
r6 and r7 are not linked to any other registers and get cached with
id=0, in the current state, they are both linked to each other with
id=A. Before this commit, check_scalar_ids would give temporary ids to
r6 and r7 (say tid1 and tid2) and then check_ids() would map tid1->A,
and when it would see tid2->A, it would not consider these state
equivalent.
Relax scalar ID equivalence by treating rold->id == 0 as "independent":
if the old state did not rely on any ID relationships for a register,
then any ID/linking present in the current state only adds constraints
and is always safe to accept for pruning. Implement this by returning
true immediately in check_scalar_ids() when old_id == 0.
Maintain correctness for the opposite direction (old_id != 0 && cur_id
== 0) by still allocating a temporary ID for cur_id == 0. This avoids
incorrectly allowing multiple independent current registers (id==0) to
satisfy a single linked old ID during mapping.
Signed-off-by: Puranjay Mohan <puranjay@kernel.org>
Link: https://lore.kernel.org/r/20260203165102.2302462-5-puranjay@kernel.org
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
The maybe_widen_reg() function widens imprecise scalar registers to
unknown when their values differ between the cached and current states.
Previously, it used regs_exact() which also compared register IDs via
check_ids(), requiring registers to have matching IDs (or mapped IDs) to
be considered exact.
For scalar widening purposes, what matters is whether the value tracking
(bounds, tnum, var_off) is the same, not whether the IDs match. Two
scalars with identical value constraints but different IDs represent the
same abstract value and don't need to be widened.
Introduce scalars_exact_for_widen() that only compares the
value-tracking portion of bpf_reg_state (fields before 'id'). This
allows the verifier to preserve more scalar value information during
state merging when IDs differ but actual tracked values are identical,
reducing unnecessary widening and potentially improving verification
precision.
Signed-off-by: Puranjay Mohan <puranjay@kernel.org>
Link: https://lore.kernel.org/r/20260203165102.2302462-4-puranjay@kernel.org
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
The verifier assigns ids to scalar registers/stack slots when they are
linked through a mov or stack spill/fill instruction. These ids are
later used to propagate newly found bounds from one register to all
registers that share the same id. The verifier also compares the ids of
these registers in current state and cached state when making pruning
decisions.
When an ID becomes singular (i.e., only a single register or stack slot
has that ID), it can no longer participate in bounds propagation. During
comparisons between current and cached states for pruning decisions,
however, such stale IDs can prevent pruning of otherwise equivalent
states.
Find and clear all singular ids before caching a state in
is_state_visited(). struct bpf_idset which is currently unused has been
repurposed for this use case.
Acked-by: Eduard Zingerman <eddyz87@gmail.com>
Signed-off-by: Puranjay Mohan <puranjay@kernel.org>
Link: https://lore.kernel.org/r/20260203165102.2302462-3-puranjay@kernel.org
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
The next commit will allow clearing of scalar ids if no other
register/stack slot has that id. This is because if only one register
has a unique id, it can't participate in bounds propagation and is
equivalent to having no id.
But if the id of a stack slot is cleared by clear_singular_ids() in the
next commit, reading that stack slot into a register will not establish
a link because the stack slot's id is cleared.
This can happen in a situation where a register is spilled and later
loses its id due to a multiply operation (for example) and then the
stack slot's id becomes singular and can be cleared.
Make sure that scalar stack slots have an id before we read them into a
register.
Acked-by: Eduard Zingerman <eddyz87@gmail.com>
Signed-off-by: Puranjay Mohan <puranjay@kernel.org>
Link: https://lore.kernel.org/r/20260203165102.2302462-2-puranjay@kernel.org
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
The added fsession does not prevent running on those architectures, that
haven't added fsession support.
For example, try to run fsession tests on arm64:
test_fsession_basic:PASS:fsession_test__open_and_load 0 nsec
test_fsession_basic:PASS:fsession_attach 0 nsec
check_result:FAIL:test_run_opts err unexpected error: -14 (errno 14)
In order to prevent such errors, add bpf_jit_supports_fsession() to guard
those architectures.
Fixes: 2d419c4465 ("bpf: add fsession support")
Acked-by: Puranjay Mohan <puranjay@kernel.org>
Tested-by: Puranjay Mohan <puranjay@kernel.org>
Signed-off-by: Leon Hwang <leon.hwang@linux.dev>
Link: https://lore.kernel.org/r/20260131144950.16294-2-leon.hwang@linux.dev
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Consolidate all logic for verifying special map fields in the single
function check_map_field_pointer().
Acked-by: Eduard Zingerman <eddyz87@gmail.com>
Signed-off-by: Mykyta Yatsenko <yatsenko@meta.com>
Link: https://lore.kernel.org/r/20260130-verif_special_fields-v2-2-2c59e637da7d@meta.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Introduce struct bpf_map_desc to hold bpf_map pointer and map uid. Use
this struct in both bpf_call_arg_meta and bpf_kfunc_call_arg_meta
instead of having different representations:
- bpf_call_arg_meta had separate map_ptr and map_uid fields
- bpf_kfunc_call_arg_meta had an anonymous inline struct
This unifies the map fields layout across both metadata structures,
making the code more consistent and preparing for further refactoring of
map field pointer validation.
Acked-by: Eduard Zingerman <eddyz87@gmail.com>
Signed-off-by: Mykyta Yatsenko <yatsenko@meta.com>
Link: https://lore.kernel.org/r/20260130-verif_special_fields-v2-1-2c59e637da7d@meta.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Allowing sleepable programs to use tail calls.
Making sure we can't mix sleepable and non-sleepable bpf programs
in tail call map (BPF_MAP_TYPE_PROG_ARRAY) and allowing it to be
used in sleepable programs.
Sleepable programs can be preempted and sleep which might bring
new source of race conditions, but both direct and indirect tail
calls should not be affected.
Direct tail calls work by patching direct jump to callee into bpf
caller program, so no problem there. We atomically switch from nop
to jump instruction.
Indirect tail call reads the callee from the map and then jumps to
it. The callee bpf program can't disappear (be released) from the
caller, because it is executed under rcu lock (rcu_read_lock_trace).
Signed-off-by: Jiri Olsa <jolsa@kernel.org>
Acked-by: Leon Hwang <leon.hwang@linux.dev>
Link: https://lore.kernel.org/r/20260130081208.1130204-2-jolsa@kernel.org
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
The BPF verifier assumes `insn_aux->nospec_result` is only set for
direct memory writes (e.g., `*(u32*)(r1+off) = r2`). However, the
assertion fails to account for helper calls (e.g.,
`bpf_skb_load_bytes_relative`) that perform writes to stack memory. Make
the check more precise to resolve this.
The problem is that `BPF_CALL` instructions have `BPF_CLASS(insn->code)
== BPF_JMP`, which triggers the warning check:
- Helpers like `bpf_skb_load_bytes_relative` write to stack memory
- `check_helper_call()` loops through `meta.access_size`, calling
`check_mem_access(..., BPF_WRITE)`
- `check_stack_write()` sets `insn_aux->nospec_result = 1`
- Since `BPF_CALL` is encoded as `BPF_JMP | BPF_CALL`, the warning fires
Execution flow:
```
1. Drop capabilities → Enable Spectre mitigation
2. Load BPF program
└─> do_check()
├─> check_cond_jmp_op() → Marks dead branch as speculative
│ └─> push_stack(..., speculative=true)
├─> pop_stack() → state->speculative = 1
├─> check_helper_call() → Processes helper in dead branch
│ └─> check_mem_access(..., BPF_WRITE)
│ └─> insn_aux->nospec_result = 1
└─> Checks: state->speculative && insn_aux->nospec_result
└─> BPF_CLASS(insn->code) == BPF_JMP → WARNING
```
To fix the assert, it would be nice to be able to reuse
bpf_insn_successors() here, but bpf_insn_successors()->cnt is not
exactly what we want as it may also be 1 for BPF_JA. Instead, we could
check opcode_info.can_jump, but then we would have to share the table
between the functions. This would mean moving the table out of the
function and adding bpf_opcode_info(). As the verifier_bug_if() only
runs for insns with nospec_result set, the impact on verification time
would likely still be negligible. However, I assume sharing
bpf_opcode_info() between liveness.c and verifier.c will not be worth
it. It seems as only adjust_jmp_off() could also be simplified using it,
and there imm/off is touched. Thus it is maybe better to rely on exact
opcode/class matching there.
Therefore, to avoid this sharing only for a verifier_bug_if(), just
check the opcode. This should now cover all opcodes for which can_jump
in bpf_insn_successors() is true.
Parts of the description and example are taken from the bug report.
Fixes: dadb59104c ("bpf: Fix aux usage after do_check_insn()")
Signed-off-by: Luis Gerhorst <luis.gerhorst@fau.de>
Reported-by: Yinhao Hu <dddddd@hust.edu.cn>
Reported-by: Kaiyan Mei <M202472210@hust.edu.cn>
Reported-by: Dongliang Mu <dzm91@hust.edu.cn>
Closes: https://lore.kernel.org/bpf/7678017d-b760-4053-a2d8-a6879b0dbeeb@hust.edu.cn/
Link: https://lore.kernel.org/r/20260127115912.3026761-2-luis.gerhorst@fau.de
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Using single ftrace_ops for direct calls update instead of allocating
ftrace_ops object for each trampoline.
With single ftrace_ops object we can use update_ftrace_direct_* api
that allows multiple ip sites updates on single ftrace_ops object.
Adding HAVE_SINGLE_FTRACE_DIRECT_OPS config option to be enabled on
each arch that supports this.
At the moment we can enable this only on x86 arch, because arm relies
on ftrace_ops object representing just single trampoline image (stored
in ftrace_ops::direct_call). Archs that do not support this will continue
to use *_ftrace_direct api.
Signed-off-by: Jiri Olsa <jolsa@kernel.org>
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Acked-by: Andrii Nakryiko <andrii@kernel.org>
Reviewed-by: Steven Rostedt (Google) <rostedt@goodmis.org>
Link: https://lore.kernel.org/bpf/20251230145010.103439-10-jolsa@kernel.org
We are going to remove "ftrace_ops->private == bpf_trampoline" setup
in following changes.
Adding ip argument to ftrace_ops_func_t callback function, so we can
use it to look up the trampoline.
Signed-off-by: Jiri Olsa <jolsa@kernel.org>
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Reviewed-by: Steven Rostedt (Google) <rostedt@goodmis.org>
Link: https://lore.kernel.org/bpf/20251230145010.103439-9-jolsa@kernel.org
At the moment the we allow the jmp attach only for ftrace_ops that
has FTRACE_OPS_FL_JMP set. This conflicts with following changes
where we use single ftrace_ops object for all direct call sites,
so all could be be attached via just call or jmp.
We already limit the jmp attach support with config option and bit
(LSB) set on the trampoline address. It turns out that's actually
enough to limit the jmp attach for architecture and only for chosen
addresses (with LSB bit set).
Each user of register_ftrace_direct or modify_ftrace_direct can set
the trampoline bit (LSB) to indicate it has to be attached by jmp.
The bpf trampoline generation code uses trampoline flags to generate
jmp-attach specific code and ftrace inner code uses the trampoline
bit (LSB) to handle return from jmp attachment, so there's no harm
to remove the FTRACE_OPS_FL_JMP bit.
The fexit/fmodret performance stays the same (did not drop),
current code:
fentry : 77.904 ± 0.546M/s
fexit : 62.430 ± 0.554M/s
fmodret : 66.503 ± 0.902M/s
with this change:
fentry : 80.472 ± 0.061M/s
fexit : 63.995 ± 0.127M/s
fmodret : 67.362 ± 0.175M/s
Fixes: 25e4e3565d ("ftrace: Introduce FTRACE_OPS_FL_JMP")
Signed-off-by: Jiri Olsa <jolsa@kernel.org>
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Acked-by: Andrii Nakryiko <andrii@kernel.org>
Reviewed-by: Steven Rostedt (Google) <rostedt@goodmis.org>
Link: https://lore.kernel.org/bpf/20251230145010.103439-2-jolsa@kernel.org
This commit fixes a security issue where BPF_PROG_DETACH on tcx or
netkit devices could be executed by any user when no program fd was
provided, bypassing permission checks. The fix adds a capability
check for CAP_NET_ADMIN or CAP_SYS_ADMIN in this case.
Fixes: e420bed025 ("bpf: Add fd-based tcx multi-prog infra with link support")
Signed-off-by: Guillaume Gonnet <ggonnet.linux@gmail.com>
Link: https://lore.kernel.org/r/20260127160200.10395-1-ggonnet.linux@gmail.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Currently, the BPF cgroup iterator supports walking descendants in
either pre-order (BPF_CGROUP_ITER_DESCENDANTS_PRE) or post-order
(BPF_CGROUP_ITER_DESCENDANTS_POST). These modes perform an exhaustive
depth-first search (DFS) of the hierarchy. In scenarios where a BPF
program may need to inspect only the direct children of a given parent
cgroup, a full DFS is unnecessarily expensive.
This patch introduces a new BPF cgroup iterator control option,
BPF_CGROUP_ITER_CHILDREN. This control option restricts the traversal
to the immediate children of a specified parent cgroup, allowing for
more targeted and efficient iteration, particularly when exhaustive
depth-first search (DFS) traversal is not required.
Signed-off-by: Matt Bobrowski <mattbobrowski@google.com>
Link: https://lore.kernel.org/r/20260127085112.3608687-1-mattbobrowski@google.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Patch series "Align atomic storage", v7.
This series adds the __aligned attribute to atomic_t and atomic64_t
definitions in include/linux and include/asm-generic (respectively) to get
natural alignment of both types on csky, m68k, microblaze, nios2, openrisc
and sh.
This series also adds Kconfig options to enable a new run-time warning to
help reveal misaligned atomic accesses on platforms which don't trap that.
The performance impact is expected to vary across platforms and workloads.
The measurements I made on m68k show that some workloads run faster and
others slower.
This patch (of 4):
Align bpf_res_spin_lock to avoid a BUILD_BUG_ON() when the alignment
changes, as it will do on m68k when, in a subsequent patch, the minimum
alignment of the atomic_t member of struct rqspinlock gets increased from
2 to 4. Drop the BUILD_BUG_ON() as it becomes redundant.
Link: https://lkml.kernel.org/r/cover.1768281748.git.fthain@linux-m68k.org
Link: https://lkml.kernel.org/r/8a83876b07d1feacc024521e44059ae89abbb1ea.1768281748.git.fthain@linux-m68k.org
Signed-off-by: Finn Thain <fthain@linux-m68k.org>
Acked-by: Alexei Starovoitov <ast@kernel.org>
Reviewed-by: Arnd Bergmann <arnd@arndb.de>
Cc: Geert Uytterhoeven <geert@linux-m68k.org>
Cc: Andrii Nakryiko <andrii@kernel.org>
Cc: Ard Biesheuvel <ardb@kernel.org>
Cc: Boqun Feng <boqun.feng@gmail.com>
Cc: "Borislav Petkov (AMD)" <bp@alien8.de>
Cc: Daniel Borkman <daniel@iogearbox.net>
Cc: Dinh Nguyen <dinguyen@kernel.org>
Cc: Eduard Zingerman <eddyz87@gmail.com>
Cc: Gary Guo <gary@garyguo.net>
Cc: Guo Ren <guoren@kernel.org>
Cc: Hao Luo <haoluo@google.com>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: John Fastabend <john.fastabend@gmail.com>
Cc: John Paul Adrian Glaubitz <glaubitz@physik.fu-berlin.de>
Cc: Jonas Bonn <jonas@southpole.se>
Cc: KP Singh <kpsingh@kernel.org>
Cc: Marc Rutland <mark.rutland@arm.com>
Cc: Martin KaFai Lau <martin.lau@linux.dev>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Rich Felker <dalias@libc.org>
Cc: Sasha Levin (Microsoft) <sashal@kernel.org>
Cc: Song Liu <song@kernel.org>
Cc: Stafford Horne <shorne@gmail.com>
Cc: Stanislav Fomichev <sdf@fomichev.me>
Cc: Stefan Kristiansson <stefan.kristiansson@saunalahti.fi>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Will Deacon <will@kernel.org>
Cc: Yonghong Song <yonghong.song@linux.dev>
Cc: Yoshinori Sato <ysato@users.sourceforge.jp>
Cc: Dave Hansen <dave.hansen@linux.intel.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Implement session cookie for fsession. The session cookies will be stored
in the stack, and the layout of the stack will look like this:
return value -> 8 bytes
argN -> 8 bytes
...
arg1 -> 8 bytes
nr_args -> 8 bytes
ip (optional) -> 8 bytes
cookie2 -> 8 bytes
cookie1 -> 8 bytes
The offset of the cookie for the current bpf program, which is in 8-byte
units, is stored in the
"(((u64 *)ctx)[-1] >> BPF_TRAMP_COOKIE_INDEX_SHIFT) & 0xFF". Therefore, we
can get the session cookie with ((u64 *)ctx)[-offset].
Implement and inline the bpf_session_cookie() for the fsession in the
verifier.
Signed-off-by: Menglong Dong <dongml2@chinatelecom.cn>
Link: https://lore.kernel.org/r/20260124062008.8657-6-dongml2@chinatelecom.cn
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
If fsession exists, we will use the bit (1 << BPF_TRAMP_IS_RETURN_SHIFT)
in ((u64 *)ctx)[-1] to store the "is_return" flag.
The logic of bpf_session_is_return() for fsession is implemented in the
verifier by inline following code:
bool bpf_session_is_return(void *ctx)
{
return (((u64 *)ctx)[-1] >> BPF_TRAMP_IS_RETURN_SHIFT) & 1;
}
Signed-off-by: Menglong Dong <dongml2@chinatelecom.cn>
Co-developed-by: Leon Hwang <leon.hwang@linux.dev>
Signed-off-by: Leon Hwang <leon.hwang@linux.dev>
Link: https://lore.kernel.org/r/20260124062008.8657-5-dongml2@chinatelecom.cn
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Add the function argument of "void *ctx" to bpf_session_cookie() and
bpf_session_is_return(), which is a preparation of the next patch.
The two kfunc is seldom used now, so it will not introduce much effect
to change their function prototype.
Signed-off-by: Menglong Dong <dongml2@chinatelecom.cn>
Acked-by: Andrii Nakryiko <andrii@kernel.org>
Link: https://lore.kernel.org/r/20260124062008.8657-4-dongml2@chinatelecom.cn
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
For now, ((u64 *)ctx)[-1] is used to store the nr_args in the trampoline.
However, 1 byte is enough to store such information. Therefore, we use
only the least significant byte of ((u64 *)ctx)[-1] to store the nr_args,
and reserve the rest for other usages.
Signed-off-by: Menglong Dong <dongml2@chinatelecom.cn>
Link: https://lore.kernel.org/r/20260124062008.8657-3-dongml2@chinatelecom.cn
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
The fsession is something that similar to kprobe session. It allow to
attach a single BPF program to both the entry and the exit of the target
functions.
Introduce the struct bpf_fsession_link, which allows to add the link to
both the fentry and fexit progs_hlist of the trampoline.
Signed-off-by: Menglong Dong <dongml2@chinatelecom.cn>
Co-developed-by: Leon Hwang <leon.hwang@linux.dev>
Signed-off-by: Leon Hwang <leon.hwang@linux.dev>
Link: https://lore.kernel.org/r/20260124062008.8657-2-dongml2@chinatelecom.cn
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
The TAS fallback can be invoked directly when queued spin locks are
disabled, and through the slow path when paravirt is enabled for queued
spin locks. In the latter case, the res_spin_lock macro will attempt the
fast path and already hold the entry when entering the slow path. This
will lead to creation of extraneous entries that are not released, which
may cause false positives for deadlock detection.
Fix this by always preceding invocation of the TAS fallback in every
case with the grabbing of the held lock entry, and add a comment to make
note of this.
Fixes: c9102a68c0 ("rqspinlock: Add a test-and-set fallback")
Reported-by: Amery Hung <ameryhung@gmail.com>
Signed-off-by: Kumar Kartikeya Dwivedi <memxor@gmail.com>
Tested-by: Amery Hung <ameryhung@gmail.com>
Link: https://lore.kernel.org/r/20260122115911.3668985-1-memxor@gmail.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
bpf_strncasecmp() function performs same like bpf_strcasecmp() except
limiting the comparison to a specific length.
Signed-off-by: Yuzuki Ishiyama <ishiyama@hpc.is.uec.ac.jp>
Acked-by: Viktor Malik <vmalik@redhat.com>
Acked-by: Mykyta Yatsenko <mykyta.yatsenko5@gmail.com>
Link: https://lore.kernel.org/r/20260121033328.1850010-2-ishiyama@hpc.is.uec.ac.jp
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
For now, bpf_get_func_arg() and bpf_get_func_arg_cnt() is not supported by
the BPF_TRACE_RAW_TP, which is not convenient to get the argument of the
tracepoint, especially for the case that the position of the arguments in
a tracepoint can change.
The target tracepoint BTF type id is specified during loading time,
therefore we can get the function argument count from the function
prototype instead of the stack.
Signed-off-by: Menglong Dong <dongml2@chinatelecom.cn>
Acked-by: Yonghong Song <yonghong.song@linux.dev>
Acked-by: Andrii Nakryiko <andrii@kernel.org>
Link: https://lore.kernel.org/r/20260121044348.113201-2-dongml2@chinatelecom.cn
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
bpf_address_lookup() has been used only in kallsyms_lookup_buildid(). It
was supposed to set @modname and @modbuildid when the symbol was in a
module.
But it always just cleared @modname because BPF symbols were never in a
module. And it did not clear @modbuildid because the pointer was not
passed.
The wrapper is no longer needed. Both @modname and @modbuildid are now
always initialized to NULL in kallsyms_lookup_buildid().
Remove the wrapper and rename __bpf_address_lookup() to
bpf_address_lookup() because this variant is used everywhere.
[akpm@linux-foundation.org: fix loongarch]
Link: https://lkml.kernel.org/r/20251128135920.217303-6-pmladek@suse.com
Fixes: 9294523e37 ("module: add printk formats to add module build ID to stacktraces")
Signed-off-by: Petr Mladek <pmladek@suse.com>
Acked-by: Alexei Starovoitov <ast@kernel.org>
Cc: Aaron Tomlin <atomlin@atomlin.com>
Cc: Daniel Borkman <daniel@iogearbox.net>
Cc: Daniel Gomez <da.gomez@samsung.com>
Cc: John Fastabend <john.fastabend@gmail.com>
Cc: Kees Cook <kees@kernel.org>
Cc: Luis Chamberalin <mcgrof@kernel.org>
Cc: Marc Rutland <mark.rutland@arm.com>
Cc: "Masami Hiramatsu (Google)" <mhiramat@kernel.org>
Cc: Petr Pavlu <petr.pavlu@suse.com>
Cc: Sami Tolvanen <samitolvanen@google.com>
Cc: Steven Rostedt (Google) <rostedt@goodmis.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Remove <linux/hex.h> from <linux/kernel.h> and update all users/callers of
hex.h interfaces to directly #include <linux/hex.h> as part of the process
of putting kernel.h on a diet.
Removing hex.h from kernel.h means that 36K C source files don't have to
pay the price of parsing hex.h for the roughly 120 C source files that
need it.
This change has been build-tested with allmodconfig on most ARCHes. Also,
all users/callers of <linux/hex.h> in the entire source tree have been
updated if needed (if not already #included).
Link: https://lkml.kernel.org/r/20251215005206.2362276-1-rdunlap@infradead.org
Signed-off-by: Randy Dunlap <rdunlap@infradead.org>
Reviewed-by: Andy Shevchenko <andriy.shevchenko@intel.com>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Yury Norov (NVIDIA) <yury.norov@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Remove lock from the bpf_timer_cancel() helper. The lock does not
protect from concurrent modification of the bpf_async_cb data fields as
those are modified in the callback without locking.
Use guard(rcu)() instead of pair of explicit lock()/unlock().
Acked-by: Kumar Kartikeya Dwivedi <memxor@gmail.com>
Acked-by: Andrii Nakryiko <andrii@kernel.org>
Signed-off-by: Mykyta Yatsenko <yatsenko@meta.com>
Link: https://lore.kernel.org/r/20260120-timer_nolock-v6-4-670ffdd787b4@meta.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Introduce bpf_async_update_prog_callback(): lock-free update of cb->prog
and cb->callback_fn. This function allows updating prog and callback_fn
fields of the struct bpf_async_cb without holding lock.
For now use it under the lock from __bpf_async_set_callback(), in the
next patches that lock will be removed.
Lock-free algorithm:
* Acquire a guard reference on prog to prevent it from being freed
during the retry loop.
* Retry loop:
1. Each iteration acquires a new prog reference and stores it
in cb->prog via xchg. The previous prog is released.
2. The loop condition checks if both cb->prog and cb->callback_fn
match what we just wrote. If either differs, a concurrent writer
overwrote our value, and we must retry.
3. When we retry, our previously-stored prog was already released by
the concurrent writer or will be released by us after
overwriting.
* Release guard reference.
Acked-by: Andrii Nakryiko <andrii@kernel.org>
Signed-off-by: Mykyta Yatsenko <yatsenko@meta.com>
Link: https://lore.kernel.org/r/20260120-timer_nolock-v6-3-670ffdd787b4@meta.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Move the timer deletion logic into a dedicated bpf_timer_delete()
helper so it can be reused by later patches.
Acked-by: Eduard Zingerman <eddyz87@gmail.com>
Acked-by: Kumar Kartikeya Dwivedi <memxor@gmail.com>
Signed-off-by: Mykyta Yatsenko <yatsenko@meta.com>
Link: https://lore.kernel.org/r/20260120-timer_nolock-v6-1-670ffdd787b4@meta.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Add check to ensure that ARG_PTR_TO_MEM is used with either MEM_WRITE or
MEM_RDONLY.
Using ARG_PTR_TO_MEM alone without flags does not make sense because:
- If the helper does not change the argument, missing MEM_RDONLY causes the
verifier to incorrectly reject a read-only buffer.
- If the helper does change the argument, missing MEM_WRITE causes the
verifier to incorrectly assume the memory is unchanged, leading to errors
in code optimization.
Co-developed-by: Shuran Liu <electronlsr@gmail.com>
Signed-off-by: Shuran Liu <electronlsr@gmail.com>
Co-developed-by: Peili Gao <gplhust955@gmail.com>
Signed-off-by: Peili Gao <gplhust955@gmail.com>
Co-developed-by: Haoran Ni <haoran.ni.cs@gmail.com>
Signed-off-by: Haoran Ni <haoran.ni.cs@gmail.com>
Signed-off-by: Zesen Liu <ftyghome@gmail.com>
Reviewed-by: Eduard Zingerman <eddyz87@gmail.com>
Link: https://lore.kernel.org/r/20260120-helper_proto-v3-2-27b0180b4e77@gmail.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
After commit 37cce22dbd ("bpf: verifier: Refactor helper access type tracking"),
the verifier started relying on the access type flags in helper
function prototypes to perform memory access optimizations.
Currently, several helper functions utilizing ARG_PTR_TO_MEM lack the
corresponding MEM_RDONLY or MEM_WRITE flags. This omission causes the
verifier to incorrectly assume that the buffer contents are unchanged
across the helper call. Consequently, the verifier may optimize away
subsequent reads based on this wrong assumption, leading to correctness
issues.
For bpf_get_stack_proto_raw_tp, the original MEM_RDONLY was incorrect
since the helper writes to the buffer. Change it to ARG_PTR_TO_UNINIT_MEM
which correctly indicates write access to potentially uninitialized memory.
Similar issues were recently addressed for specific helpers in commit
ac44dcc788 ("bpf: Fix verifier assumptions of bpf_d_path's output buffer")
and commit 2eb7648558 ("bpf: Specify access type of bpf_sysctl_get_name args").
Fix these prototypes by adding the correct memory access flags.
Fixes: 37cce22dbd ("bpf: verifier: Refactor helper access type tracking")
Co-developed-by: Shuran Liu <electronlsr@gmail.com>
Signed-off-by: Shuran Liu <electronlsr@gmail.com>
Co-developed-by: Peili Gao <gplhust955@gmail.com>
Signed-off-by: Peili Gao <gplhust955@gmail.com>
Co-developed-by: Haoran Ni <haoran.ni.cs@gmail.com>
Signed-off-by: Haoran Ni <haoran.ni.cs@gmail.com>
Signed-off-by: Zesen Liu <ftyghome@gmail.com>
Acked-by: Eduard Zingerman <eddyz87@gmail.com>
Link: https://lore.kernel.org/r/20260120-helper_proto-v3-1-27b0180b4e77@gmail.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
This patch implements range tracking (interval analysis) for BPF_DIV and
BPF_MOD operations when the divisor is a constant, covering both signed
and unsigned variants.
While LLVM typically optimizes integer division and modulo by constants
into multiplication and shift sequences, this optimization is less
effective for the BPF target when dealing with 64-bit arithmetic.
Currently, the verifier does not track bounds for scalar division or
modulo, treating the result as "unbounded". This leads to false positive
rejections for safe code patterns.
For example, the following code (compiled with -O2):
```c
int test(struct pt_regs *ctx) {
char buffer[6] = {1};
__u64 x = bpf_ktime_get_ns();
__u64 res = x % sizeof(buffer);
char value = buffer[res];
bpf_printk("res = %llu, val = %d", res, value);
return 0;
}
```
Generates a raw `BPF_MOD64` instruction:
```asm
; __u64 res = x % sizeof(buffer);
1: 97 00 00 00 06 00 00 00 r0 %= 0x6
; char value = buffer[res];
2: 18 01 00 00 00 00 00 00 00 00 00 00 00 00 00 00 r1 = 0x0 ll
4: 0f 01 00 00 00 00 00 00 r1 += r0
5: 91 14 00 00 00 00 00 00 r4 = *(s8 *)(r1 + 0x0)
```
Without this patch, the verifier fails with "math between map_value
pointer and register with unbounded min value is not allowed" because
it cannot deduce that `r0` is within [0, 5].
According to the BPF instruction set[1], the instruction's offset field
(`insn->off`) is used to distinguish between signed (`off == 1`) and
unsigned division (`off == 0`). Moreover, we also follow the BPF division
and modulo runtime behavior (semantics) to handle special cases, such as
division by zero and signed division overflow.
- UDIV: dst = (src != 0) ? (dst / src) : 0
- SDIV: dst = (src == 0) ? 0 : ((src == -1 && dst == LLONG_MIN) ? LLONG_MIN : (dst / src))
- UMOD: dst = (src != 0) ? (dst % src) : dst
- SMOD: dst = (src == 0) ? dst : ((src == -1 && dst == LLONG_MIN) ? 0: (dst s% src))
Here is the overview of the changes made in this patch (See the code comments
for more details and examples):
1. For BPF_DIV: Firstly check whether the divisor is zero. If so, set the
destination register to zero (matching runtime behavior).
For non-zero constant divisors: goto `scalar(32)?_min_max_(u|s)div` functions.
- General cases: compute the new range by dividing max_dividend and
min_dividend by the constant divisor.
- Overflow case (SIGNED_MIN / -1) in signed division: mark the result
as unbounded if the dividend is not a single number.
2. For BPF_MOD: Firstly check whether the divisor is zero. If so, leave the
destination register unchanged (matching runtime behavior).
For non-zero constant divisors: goto `scalar(32)?_min_max_(u|s)mod` functions.
- General case: For signed modulo, the result's sign matches the
dividend's sign. And the result's absolute value is strictly bounded
by `min(abs(dividend), abs(divisor) - 1)`.
- Special care is taken when the divisor is SIGNED_MIN. By casting
to unsigned before negation and subtracting 1, we avoid signed
overflow and correctly calculate the maximum possible magnitude
(`res_max_abs` in the code).
- "Small dividend" case: If the dividend is already within the possible
result range (e.g., [-2, 5] % 10), the operation is an identity
function, and the destination register remains unchanged.
3. In `scalar(32)?_min_max_(u|s)(div|mod)` functions: After updating current
range, reset other ranges and tnum to unbounded/unknown.
e.g., in `scalar_min_max_sdiv`, signed 64-bit range is updated. Then reset
unsigned 64-bit range and 32-bit range to unbounded, and tnum to unknown.
Exception: in BPF_MOD's "small dividend" case, since the result remains
unchanged, we do not reset other ranges/tnum.
4. Also updated existing selftests based on the expected BPF_DIV and
BPF_MOD behavior.
[1] https://www.kernel.org/doc/Documentation/bpf/standardization/instruction-set.rst
Co-developed-by: Shenghao Yuan <shenghaoyuan0928@163.com>
Signed-off-by: Shenghao Yuan <shenghaoyuan0928@163.com>
Co-developed-by: Tianci Cao <ziye@zju.edu.cn>
Signed-off-by: Tianci Cao <ziye@zju.edu.cn>
Signed-off-by: Yazhou Tang <tangyazhou518@outlook.com>
Tested-by: syzbot@syzkaller.appspotmail.com
Link: https://lore.kernel.org/r/20260119085458.182221-2-tangyazhou@zju.edu.cn
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Implement bpf_stream_vprintk with an implicit bpf_prog_aux argument,
and remote bpf_stream_vprintk_impl from the kernel.
Update the selftests to use the new API with implicit argument.
bpf_stream_vprintk macro is changed to use the new bpf_stream_vprintk
kfunc, and the extern definition of bpf_stream_vprintk_impl is
replaced accordingly.
Reviewed-by: Eduard Zingerman <eddyz87@gmail.com>
Signed-off-by: Ihor Solodrai <ihor.solodrai@linux.dev>
Link: https://lore.kernel.org/r/20260120222638.3976562-11-ihor.solodrai@linux.dev
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Implement bpf_task_work_schedule_* with an implicit bpf_prog_aux
argument, and remove corresponding _impl funcs from the kernel.
Update special kfunc checks in the verifier accordingly.
Update the selftests to use the new API with implicit argument.
Reviewed-by: Eduard Zingerman <eddyz87@gmail.com>
Signed-off-by: Ihor Solodrai <ihor.solodrai@linux.dev>
Link: https://lore.kernel.org/r/20260120222638.3976562-10-ihor.solodrai@linux.dev
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Implement bpf_wq_set_callback() with an implicit bpf_prog_aux
argument, and remove bpf_wq_set_callback_impl().
Update special kfunc checks in the verifier accordingly.
Reviewed-by: Eduard Zingerman <eddyz87@gmail.com>
Signed-off-by: Ihor Solodrai <ihor.solodrai@linux.dev>
Link: https://lore.kernel.org/r/20260120222638.3976562-8-ihor.solodrai@linux.dev
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
A kernel function bpf_foo marked with KF_IMPLICIT_ARGS flag is
expected to have two associated types in BTF:
* `bpf_foo` with a function prototype that omits implicit arguments
* `bpf_foo_impl` with a function prototype that matches the kernel
declaration of `bpf_foo`, but doesn't have a ksym associated with
its name
In order to support kfuncs with implicit arguments, the verifier has
to know how to resolve a call of `bpf_foo` to the correct BTF function
prototype and address.
To implement this, in add_kfunc_call() kfunc flags are checked for
KF_IMPLICIT_ARGS. For such kfuncs a BTF func prototype is adjusted to
the one found for `bpf_foo_impl` (func_name + "_impl" suffix, by
convention) function in BTF.
This effectively changes the signature of the `bpf_foo` kfunc in the
context of verification: from one without implicit args to the one
with full argument list.
The values of implicit arguments by design are provided by the
verifier, and so they can only be of particular types. In this patch
the only allowed implicit arg type is a pointer to struct
bpf_prog_aux.
In order for the verifier to correctly set an implicit bpf_prog_aux
arg value at runtime, is_kfunc_arg_prog() is extended to check for the
arg type. At a point when prog arg is determined in check_kfunc_args()
the kfunc with implicit args already has a prototype with full
argument list, so the existing value patch mechanism just works.
If a new kfunc with KF_IMPLICIT_ARG is declared for an existing kfunc
that uses a __prog argument (a legacy case), the prototype
substitution works in exactly the same way, assuming the kfunc follows
the _impl naming convention. The difference is only in how _impl
prototype is added to the BTF, which is not the verifier's
concern. See a subsequent resolve_btfids patch for details.
__prog suffix is still supported at this point, but will be removed in
a subsequent patch, after current users are moved to KF_IMPLICIT_ARGS.
Introduction of KF_IMPLICIT_ARGS revealed an issue with zero-extension
tracking, because an explicit rX = 0 in place of the verifier-supplied
argument is now absent if the arg is implicit (the BPF prog doesn't
pass a dummy NULL anymore). To mitigate this, reset the subreg_def of
all caller saved registers in check_kfunc_call() [1].
[1] https://lore.kernel.org/bpf/b4a760ef828d40dac7ea6074d39452bb0dc82caa.camel@gmail.com/
Acked-by: Eduard Zingerman <eddyz87@gmail.com>
Signed-off-by: Ihor Solodrai <ihor.solodrai@linux.dev>
Link: https://lore.kernel.org/r/20260120222638.3976562-4-ihor.solodrai@linux.dev
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
There is code duplication between add_kfunc_call() and
fetch_kfunc_meta() collecting information about a kfunc from BTF.
Introduce struct bpf_kfunc_meta to hold common kfunc BTF data and
implement fetch_kfunc_meta() to fill it in, instead of struct
bpf_kfunc_call_arg_meta directly.
Then use these in add_kfunc_call() and (new) fetch_kfunc_arg_meta()
functions, and fixup previous usages of fetch_kfunc_meta() to
fetch_kfunc_arg_meta().
Besides the code dedup, this change enables add_kfunc_call() to access
kfunc->flags.
Acked-by: Eduard Zingerman <eddyz87@gmail.com>
Signed-off-by: Ihor Solodrai <ihor.solodrai@linux.dev>
Link: https://lore.kernel.org/r/20260120222638.3976562-3-ihor.solodrai@linux.dev
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
btf_kfunc_id_set_contains() is called by fetch_kfunc_meta() in the BPF
verifier to get the kfunc flags stored in the .BTF_ids ELF section.
If it returns NULL instead of a valid pointer, it's interpreted as an
illegal kfunc usage failing the verification.
There are two potential reasons for btf_kfunc_id_set_contains() to
return NULL:
1. Provided kfunc BTF id is not present in relevant kfunc id sets.
2. The kfunc is not allowed, as determined by the program type
specific filter [1].
The filter functions accept a pointer to `struct bpf_prog`, so they
might implicitly depend on earlier stages of verification, when
bpf_prog members are set.
For example, bpf_qdisc_kfunc_filter() in linux/net/sched/bpf_qdisc.c
inspects prog->aux->st_ops [2], which is initialized in:
check_attach_btf_id() -> check_struct_ops_btf_id()
So far this hasn't been an issue, because fetch_kfunc_meta() is the
only caller of btf_kfunc_id_set_contains().
However in subsequent patches of this series it is necessary to
inspect kfunc flags earlier in BPF verifier, in the add_kfunc_call().
To resolve this, refactor btf_kfunc_id_set_contains() into two
interface functions:
* btf_kfunc_flags() that simply returns pointer to kfunc_flags
without applying the filters
* btf_kfunc_is_allowed() that both checks for kfunc_flags existence
(which is a requirement for a kfunc to be allowed) and applies the
prog filters
See [3] for the previous version of this patch.
[1] https://lore.kernel.org/all/20230519225157.760788-7-aditi.ghag@isovalent.com/
[2] https://lore.kernel.org/all/20250409214606.2000194-4-ameryhung@gmail.com/
[3] https://lore.kernel.org/bpf/20251029190113.3323406-3-ihor.solodrai@linux.dev/
Reviewed-by: Eduard Zingerman <eddyz87@gmail.com>
Signed-off-by: Ihor Solodrai <ihor.solodrai@linux.dev>
Link: https://lore.kernel.org/r/20260120222638.3976562-2-ihor.solodrai@linux.dev
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Currently, reset_idmap_scratch() performs a 4.7KB memset() in every
states_equal() call. Optimize this by using a counter to track used
ID mappings, replacing the O(N) memset() with an O(1) reset and
bounding the search loop in check_ids().
Signed-off-by: Qiliang Yuan <realwujing@gmail.com>
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Acked-by: Eduard Zingerman <eddyz87@gmail.com>
Link: https://lore.kernel.org/bpf/20260120023234.77673-1-realwujing@gmail.com
After commit 4fa8d68aa5 ("bpf: Convert hashtab.c to rqspinlock")
we no longer use HASHTAB_MAP_LOCK_{COUNT,MASK} as the per-CPU
map_locked[HASHTAB_MAP_LOCK_COUNT] array got removed from struct
bpf_htab. Right now it is still accounted for in htab_map_mem_usage.
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Link: https://lore.kernel.org/bpf/09703eb6bb249f12b1d5253b5a50a0c4fa239d27.1768913513.git.daniel@iogearbox.net
sync_linked_regs() is called after a conditional jump to propagate new
bounds of a register to all its liked registers. But the verifier log
only prints the state of the register that is part of the conditional
jump.
Make sync_linked_regs() scratch the registers whose bounds have been
updated by propagation from a known register.
Before:
0: (85) call bpf_get_prandom_u32#7 ; R0=scalar()
1: (57) r0 &= 255 ; R0=scalar(smin=smin32=0,smax=umax=smax32=umax32=255,var_off=(0x0; 0xff))
2: (bf) r1 = r0 ; R0=scalar(id=1,smin=smin32=0,smax=umax=smax32=umax32=255,var_off=(0x0; 0xff)) R1=scalar(id=1,smin=smin32=0,smax=umax=smax32=umax32=255,var_off=(0x0; 0xff))
3: (07) r1 += 4 ; R1=scalar(id=1+4,smin=umin=smin32=umin32=4,smax=umax=smax32=umax32=259,var_off=(0x0; 0x1ff))
4: (a5) if r1 < 0xa goto pc+2 ; R1=scalar(id=1+4,smin=umin=smin32=umin32=10,smax=umax=smax32=umax32=259,var_off=(0x0; 0x1ff))
5: (35) if r0 >= 0x6 goto pc+1
After:
0: (85) call bpf_get_prandom_u32#7 ; R0=scalar()
1: (57) r0 &= 255 ; R0=scalar(smin=smin32=0,smax=umax=smax32=umax32=255,var_off=(0x0; 0xff))
2: (bf) r1 = r0 ; R0=scalar(id=1,smin=smin32=0,smax=umax=smax32=umax32=255,var_off=(0x0; 0xff)) R1=scalar(id=1,smin=smin32=0,smax=umax=smax32=umax32=255,var_off=(0x0; 0xff))
3: (07) r1 += 4 ; R1=scalar(id=1+4,smin=umin=smin32=umin32=4,smax=umax=smax32=umax32=259,var_off=(0x0; 0x1ff))
4: (a5) if r1 < 0xa goto pc+2 ; R0=scalar(id=1+0,smin=umin=smin32=umin32=6,smax=umax=smax32=umax32=255) R1=scalar(id=1+4,smin=umin=smin32=umin32=10,smax=umax=smax32=umax32=259,var_off=(0x0; 0x1ff))
5: (35) if r0 >= 0x6 goto pc+1
The conditional jump in 4 updates the bound of R1 and the new bounds are
propogated to R0 as it is linked with the same id, before this change,
verifier only printed the state for R1 but after it prints for both R0
and R1.
Suggested-by: Andrii Nakryiko <andrii.nakryiko@gmail.com>
Signed-off-by: Puranjay Mohan <puranjay@kernel.org>
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Acked-by: Yonghong Song <yonghong.song@linux.dev>
Link: https://lore.kernel.org/bpf/20260116141436.3715322-1-puranjay@kernel.org
Add GPL-2.0 SPDX-License-Identifier lines to some files,
and remove a reference to COPYING, and boilerplate warranty
text, from offload.c.
Signed-off-by: Tim Bird <tim.bird@sony.com>
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Link: https://lore.kernel.org/bpf/20260115013129.598705-1-tim.bird@sony.com
sync_linked_regs() copies the id of known_reg to reg when propagating
bounds of known_reg to reg using the off of known_reg, but when
known_reg was linked to reg like:
known_reg = reg ; both known_reg and reg get same id
known_reg += 4 ; known_reg gets off = 4, and its id gets BPF_ADD_CONST
now when a call to sync_linked_regs() happens, let's say with the following:
if known_reg >= 10 goto pc+2
known_reg's new bounds are propagated to reg but now reg gets
BPF_ADD_CONST from the copy.
This means if another link to reg is created like:
another_reg = reg ; another_reg should get the id of reg but
assign_scalar_id_before_mov() sees
BPF_ADD_CONST on reg and assigns a new id to it.
As reg has a new id now, known_reg's link to reg is broken. If we find
new bounds for known_reg, they will not be propagated to reg.
This can be seen in the selftest added in the next commit:
0: (85) call bpf_get_prandom_u32#7 ; R0=scalar()
1: (57) r0 &= 255 ; R0=scalar(smin=smin32=0,smax=umax=smax32=umax32=255,var_off=(0x0; 0xff))
2: (bf) r1 = r0 ; R0=scalar(id=1,smin=smin32=0,smax=umax=smax32=umax32=255,var_off=(0x0; 0xff)) R1=scalar(id=1,smin=smin32=0,smax=umax=smax32=umax32=255,var_off=(0x0; 0xff))
3: (07) r1 += 4 ; R1=scalar(id=1+4,smin=umin=smin32=umin32=4,smax=umax=smax32=umax32=259,var_off=(0x0; 0x1ff))
4: (a5) if r1 < 0xa goto pc+4 ; R1=scalar(id=1+4,smin=umin=smin32=umin32=10,smax=umax=smax32=umax32=259,var_off=(0x0; 0x1ff))
5: (bf) r2 = r0 ; R0=scalar(id=2,smin=umin=smin32=umin32=6,smax=umax=smax32=umax32=255) R2=scalar(id=2,smin=umin=smin32=umin32=6,smax=umax=smax32=umax32=255)
6: (a5) if r1 < 0xe goto pc+2 ; R1=scalar(id=1+4,smin=umin=smin32=umin32=14,smax=umax=smax32=umax32=259,var_off=(0x0; 0x1ff))
7: (35) if r0 >= 0xa goto pc+1 ; R0=scalar(id=2,smin=umin=smin32=umin32=6,smax=umax=smax32=umax32=9,var_off=(0x0; 0xf))
8: (37) r0 /= 0
div by zero
When 4 is verified, r1's bounds are propagated to r0 but r0 also gets
BPF_ADD_CONST (bug).
When 5 is verified, r0 gets a new id (2) and its link with r1 is broken.
After 6 we know r1 has bounds [14, 259] and therefore r0 should have
bounds [10, 255], therefore the branch at 7 is always taken. But because
r0's id was changed to 2, r1's new bounds are not propagated to r0.
The verifier still thinks r0 has bounds [6, 255] before 7 and execution
can reach div by zero.
Fix this by preserving id in sync_linked_regs() like off and subreg_def.
Fixes: 98d7ca374b ("bpf: Track delta between "linked" registers.")
Signed-off-by: Puranjay Mohan <puranjay@kernel.org>
Acked-by: Eduard Zingerman <eddyz87@gmail.com>
Link: https://lore.kernel.org/r/20260115151143.1344724-2-puranjay@kernel.org
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
For a `gotox rX` instruction the rX register should be marked as used
in the compute_insn_live_regs() function. Fix this.
Signed-off-by: Anton Protopopov <a.s.protopopov@gmail.com>
Link: https://lore.kernel.org/r/20260114162544.83253-2-a.s.protopopov@gmail.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Cross-merge BPF and other fixes after downstream PR.
No conflicts.
Adjacent:
Auto-merging MAINTAINERS
Auto-merging Makefile
Auto-merging kernel/bpf/verifier.c
Auto-merging kernel/sched/ext.c
Auto-merging mm/memcontrol.c
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
The insn_array_map_direct_value_addr() function currently returns
-EINVAL when the offset within the map is invalid. Change this to
return -EACCES, so that it is consistent with similar boundary access
checks in the verifier.
Signed-off-by: Anton Protopopov <a.s.protopopov@gmail.com>
Reviewed-by: Emil Tsalapatis <emil@etsalapatis.com>
Link: https://lore.kernel.org/r/20260111153047.8388-3-a.s.protopopov@gmail.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
The map_direct_value_addr() function of the instruction
array map incorrectly adds offset to the resulting address.
This is a bug, because later the resolve_pseudo_ldimm64()
function adds the offset. Fix it. Corresponding selftests
are added in a consequent commit.
Fixes: 493d9e0d60 ("bpf, x86: add support for indirect jumps")
Signed-off-by: Anton Protopopov <a.s.protopopov@gmail.com>
Reviewed-by: Emil Tsalapatis <emil@etsalapatis.com>
Link: https://lore.kernel.org/r/20260111153047.8388-2-a.s.protopopov@gmail.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Teach the BPF verifier to treat pointers to struct types returned from
BPF kfuncs as implicitly trusted (PTR_TO_BTF_ID | PTR_TRUSTED) by
default. Returning untrusted pointers to struct types from BPF kfuncs
should be considered an exception only, and certainly not the norm.
Update existing selftests to reflect the change in register type
printing (e.g. `ptr_` becoming `trusted_ptr_` in verifier error
messages).
Link: https://lore.kernel.org/bpf/aV4nbCaMfIoM0awM@google.com/
Signed-off-by: Matt Bobrowski <mattbobrowski@google.com>
Acked-by: Kumar Kartikeya Dwivedi <memxor@gmail.com>
Link: https://lore.kernel.org/r/20260113083949.2502978-1-mattbobrowski@google.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Currently, vmlinux BTF is unconditionally sorted during
the build phase. The function btf_find_by_name_kind
executes the binary search branch, so find_bpffs_btf_enums
can be optimized by using btf_find_by_name_kind.
Signed-off-by: Donglin Peng <pengdonglin@xiaomi.com>
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Acked-by: Eduard Zingerman <eddyz87@gmail.com>
Link: https://lore.kernel.org/bpf/20260109130003.3313716-10-dolinux.peng@gmail.com
Currently, vmlinux and kernel module BTFs are unconditionally
sorted during the build phase, with named types placed at the
end. Thus, anonymous types should be skipped when starting the
search. In my vmlinux BTF, the number of anonymous types is
61,747, which means the loop count can be reduced by 61,747.
Signed-off-by: Donglin Peng <pengdonglin@xiaomi.com>
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Acked-by: Eduard Zingerman <eddyz87@gmail.com>
Link: https://lore.kernel.org/bpf/20260109130003.3313716-9-dolinux.peng@gmail.com
This patch checks whether the BTF is sorted by name in ascending order.
If sorted, binary search will be used when looking up types.
Specifically, vmlinux and kernel module BTFs are always sorted during
the build phase with anonymous types placed before named types, so we
only need to identify the starting ID of named types.
Signed-off-by: Donglin Peng <pengdonglin@xiaomi.com>
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Link: https://lore.kernel.org/bpf/20260109130003.3313716-8-dolinux.peng@gmail.com
Improve btf_find_by_name_kind() performance by adding binary search
support for sorted types. Falls back to linear search for compatibility.
Signed-off-by: Donglin Peng <pengdonglin@xiaomi.com>
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Link: https://lore.kernel.org/bpf/20260109130003.3313716-7-dolinux.peng@gmail.com
cilium bpf_wiregard.bpf.c when compiled with -O1 fails to load
with the following verifier log:
192: (79) r2 = *(u64 *)(r10 -304) ; R2=pkt(r=40) R10=fp0 fp-304=pkt(r=40)
...
227: (85) call bpf_skb_store_bytes#9 ; R0=scalar()
228: (bc) w2 = w0 ; R0=scalar() R2=scalar(smin=0,smax=umax=0xffffffff,var_off=(0x0; 0xffffffff))
229: (c4) w2 s>>= 31 ; R2=scalar(smin=0,smax=umax=0xffffffff,smin32=-1,smax32=0,var_off=(0x0; 0xffffffff))
230: (54) w2 &= -134 ; R2=scalar(smin=0,smax=umax=umax32=0xffffff7a,smax32=0x7fffff7a,var_off=(0x0; 0xffffff7a))
...
232: (66) if w2 s> 0xffffffff goto pc+125 ; R2=scalar(smin=umin=umin32=0x80000000,smax=umax=umax32=0xffffff7a,smax32=-134,var_off=(0x80000000; 0x7fffff7a))
...
238: (79) r4 = *(u64 *)(r10 -304) ; R4=scalar() R10=fp0 fp-304=scalar()
239: (56) if w2 != 0xffffff78 goto pc+210 ; R2=0xffffff78 // -136
...
258: (71) r1 = *(u8 *)(r4 +0)
R4 invalid mem access 'scalar'
The error might confuse most bpf authors, since fp-304 slot had 'pkt'
pointer at insn 192 and became 'scalar' at 238. That happened because
bpf_skb_store_bytes() clears all packet pointers including those in
the stack. On the first glance it might look like a bug in the source
code, since ctx->data pointer should have been reloaded after the call
to bpf_skb_store_bytes().
The relevant part of cilium source code looks like this:
// bpf/lib/nodeport.h
int dsr_set_ipip6()
{
if (ctx_adjust_hroom(...))
return DROP_INVALID; // -134
if (ctx_store_bytes(...))
return DROP_WRITE_ERROR; // -141
return 0;
}
bool dsr_fail_needs_reply(int code)
{
if (code == DROP_FRAG_NEEDED) // -136
return true;
return false;
}
tail_nodeport_ipv6_dsr()
{
ret = dsr_set_ipip6(...);
if (!IS_ERR(ret)) {
...
} else {
if (dsr_fail_needs_reply(ret))
return dsr_reply_icmp6(...);
}
}
The code doesn't have arithmetic shift by 31 and it reloads ctx->data
every time it needs to access it. So it's not a bug in the source code.
The reason is DAGCombiner::foldSelectCCToShiftAnd() LLVM transformation:
// If this is a select where the false operand is zero and the compare is a
// check of the sign bit, see if we can perform the "gzip trick":
// select_cc setlt X, 0, A, 0 -> and (sra X, size(X)-1), A
// select_cc setgt X, 0, A, 0 -> and (not (sra X, size(X)-1)), A
The conditional branch in dsr_set_ipip6() and its return values
are optimized into BPF_ARSH plus BPF_AND:
227: (85) call bpf_skb_store_bytes#9
228: (bc) w2 = w0
229: (c4) w2 s>>= 31 ; R2=scalar(smin=0,smax=umax=0xffffffff,smin32=-1,smax32=0,var_off=(0x0; 0xffffffff))
230: (54) w2 &= -134 ; R2=scalar(smin=0,smax=umax=umax32=0xffffff7a,smax32=0x7fffff7a,var_off=(0x0; 0xffffff7a))
after insn 230 the register w2 can only be 0 or -134,
but the verifier approximates it, since there is no way to
represent two scalars in bpf_reg_state.
After fallthough at insn 232 the w2 can only be -134,
hence the branch at insn
239: (56) if w2 != -136 goto pc+210
should be always taken, and trapping insn 258 should never execute.
LLVM generated correct code, but the verifier follows impossible
path and rejects valid program. To fix this issue recognize this
special LLVM optimization and fork the verifier state.
So after insn 229: (c4) w2 s>>= 31
the verifier has two states to explore:
one with w2 = 0 and another with w2 = 0xffffffff
which makes the verifier accept bpf_wiregard.c
A similar pattern exists were OR operation is used in place of the AND
operation, the verifier detects that pattern as well by forking the
state before the OR operation with a scalar in range [-1,0].
Note there are 20+ such patterns in bpf_wiregard.o compiled
with -O1 and -O2, but they're rarely seen in other production
bpf programs, so push_stack() approach is not a concern.
Reported-by: Hao Sun <sunhao.th@gmail.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Co-developed-by: Puranjay Mohan <puranjay@kernel.org>
Signed-off-by: Puranjay Mohan <puranjay@kernel.org>
Link: https://lore.kernel.org/r/20260112201424.816836-2-puranjay@kernel.org
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Replace the pattern of declaring a local regs array from cur_regs()
and then indexing into it with the more concise reg_state() helper.
This simplifies the code by eliminating intermediate variables and
makes register access more consistent throughout the verifier.
Signed-off-by: Mykyta Yatsenko <yatsenko@meta.com>
Acked-by: Andrii Nakryiko <andrii@kernel.org>
Link: https://lore.kernel.org/r/20260113134826.2214860-1-mykyta.yatsenko5@gmail.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Ensure that registered destructor kfuncs have the same type
as btf_dtor_kfunc_t to avoid a kernel panic on systems with
CONFIG_CFI enabled.
Signed-off-by: Sami Tolvanen <samitolvanen@google.com>
Acked-by: Yonghong Song <yonghong.song@linux.dev>
Link: https://lore.kernel.org/r/20260110082548.113748-10-samitolvanen@google.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
With CONFIG_CFI enabled, the kernel strictly enforces that indirect
function calls use a function pointer type that matches the target
function. I ran into the following type mismatch when running BPF
self-tests:
CFI failure at bpf_obj_free_fields+0x190/0x238 (target:
bpf_crypto_ctx_release+0x0/0x94; expected type: 0xa488ebfc)
Internal error: Oops - CFI: 00000000f2008228 [#1] SMP
...
As bpf_crypto_ctx_release() is also used in BPF programs and using
a void pointer as the argument would make the verifier unhappy, add
a simple stub function with the correct type and register it as the
destructor kfunc instead.
Signed-off-by: Sami Tolvanen <samitolvanen@google.com>
Acked-by: Yonghong Song <yonghong.song@linux.dev>
Tested-by: Viktor Malik <vmalik@redhat.com>
Link: https://lore.kernel.org/r/20260110082548.113748-7-samitolvanen@google.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
BPF_MAP_TYPE_INSN_ARRAY maps store instruction pointers in their
ips array, not string data. The map_direct_value_addr callback for
this map type returns the address of the ips array, which is not
suitable for use as a constant string argument.
When a BPF program passes a pointer to an insn_array map value as
ARG_PTR_TO_CONST_STR (e.g., to bpf_snprintf), the verifier's
null-termination check in check_reg_const_str() operates on the
wrong memory region, and at runtime bpf_bprintf_prepare() can read
out of bounds searching for a null terminator.
Reject BPF_MAP_TYPE_INSN_ARRAY in check_reg_const_str() since this
map type is not designed to hold string data.
Reported-by: syzbot+2c29addf92581b410079@syzkaller.appspotmail.com
Closes: https://syzkaller.appspot.com/bug?extid=2c29addf92581b410079
Tested-by: syzbot+2c29addf92581b410079@syzkaller.appspotmail.com
Fixes: 493d9e0d60 ("bpf, x86: add support for indirect jumps")
Signed-off-by: Deepanshu Kartikey <kartikey406@gmail.com>
Acked-by: Anton Protopopov <a.s.protopopov@gmail.com>
Link: https://lore.kernel.org/r/20260107021037.289644-1-kartikey406@gmail.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Introduce BPF_F_ALL_CPUS flag support for percpu_cgroup_storage maps to
allow updating values for all CPUs with a single value for update_elem
API.
Introduce BPF_F_CPU flag support for percpu_cgroup_storage maps to
allow:
* update value for specified CPU for update_elem API.
* lookup value for specified CPU for lookup_elem API.
The BPF_F_CPU flag is passed via map_flags along with embedded cpu info.
Signed-off-by: Leon Hwang <leon.hwang@linux.dev>
Link: https://lore.kernel.org/r/20260107022022.12843-6-leon.hwang@linux.dev
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Copy map value using 'copy_map_value_long()'. It's to keep consistent
style with the way of other percpu maps.
No functional change intended.
Signed-off-by: Leon Hwang <leon.hwang@linux.dev>
Link: https://lore.kernel.org/r/20260107022022.12843-5-leon.hwang@linux.dev
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Introduce BPF_F_ALL_CPUS flag support for percpu_hash and lru_percpu_hash
maps to allow updating values for all CPUs with a single value for both
update_elem and update_batch APIs.
Introduce BPF_F_CPU flag support for percpu_hash and lru_percpu_hash
maps to allow:
* update value for specified CPU for both update_elem and update_batch
APIs.
* lookup value for specified CPU for both lookup_elem and lookup_batch
APIs.
The BPF_F_CPU flag is passed via:
* map_flags along with embedded cpu info.
* elem_flags along with embedded cpu info.
Signed-off-by: Leon Hwang <leon.hwang@linux.dev>
Link: https://lore.kernel.org/r/20260107022022.12843-4-leon.hwang@linux.dev
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Introduce support for the BPF_F_ALL_CPUS flag in percpu_array maps to
allow updating values for all CPUs with a single value for both
update_elem and update_batch APIs.
Introduce support for the BPF_F_CPU flag in percpu_array maps to allow:
* update value for specified CPU for both update_elem and update_batch
APIs.
* lookup value for specified CPU for both lookup_elem and lookup_batch
APIs.
The BPF_F_CPU flag is passed via:
* map_flags of lookup_elem and update_elem APIs along with embedded cpu
info.
* elem_flags of lookup_batch and update_batch APIs along with embedded
cpu info.
Signed-off-by: Leon Hwang <leon.hwang@linux.dev>
Link: https://lore.kernel.org/r/20260107022022.12843-3-leon.hwang@linux.dev
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Introduce BPF_F_CPU and BPF_F_ALL_CPUS flags and check them for
following APIs:
* 'map_lookup_elem()'
* 'map_update_elem()'
* 'generic_map_lookup_batch()'
* 'generic_map_update_batch()'
And, get the correct value size for these APIs.
Acked-by: Andrii Nakryiko <andrii@kernel.org>
Signed-off-by: Leon Hwang <leon.hwang@linux.dev>
Link: https://lore.kernel.org/r/20260107022022.12843-2-leon.hwang@linux.dev
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
The bpf_arena_*_pages() kfuncs can be called from sleepable contexts,
but the verifier still prevents BPF programs from calling them while
holding a spinlock. Amend the verifier to allow for BPF programs
calling arena page management functions while holding a lock.
Signed-off-by: Emil Tsalapatis <emil@etsalapatis.com>
Link: https://lore.kernel.org/r/20260106-arena-under-lock-v2-2-378e9eab3066@etsalapatis.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
The in_sleepable_context() function is used to specialize the BPF code
in do_misc_fixups(). With the addition of nonsleepable arena kfuncs,
there are kfuncs whose specialization depends on whether we are
holding a lock. We should use the nonsleepable version while
holding a lock and the sleepable one when not.
Add a check for active_locks to account for locking when specializing
arena kfuncs.
Signed-off-by: Emil Tsalapatis <emil@etsalapatis.com>
Link: https://lore.kernel.org/r/20260106-arena-under-lock-v2-1-378e9eab3066@etsalapatis.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
The __opt annotation was originally introduced specifically for
buffer/size argument pairs in bpf_dynptr_slice() and
bpf_dynptr_slice_rdwr(), allowing the buffer pointer to be NULL while
still validating the size as a constant. The __nullable annotation
serves the same purpose but is more general and is already used
throughout the BPF subsystem for raw tracepoints, struct_ops, and other
kfuncs.
This patch unifies the two annotations by replacing __opt with
__nullable. The key change is in the verifier's
get_kfunc_ptr_arg_type() function, where mem/size pair detection is now
performed before the nullable check. This ensures that buffer/size
pairs are correctly classified as KF_ARG_PTR_TO_MEM_SIZE even when the
buffer is nullable, while adding an !arg_mem_size condition to the
nullable check prevents interference with mem/size pair handling.
When processing KF_ARG_PTR_TO_MEM_SIZE arguments, the verifier now uses
is_kfunc_arg_nullable() instead of the removed is_kfunc_arg_optional()
to determine whether to skip size validation for NULL buffers.
This is the first documentation added for the __nullable annotation,
which has been in use since it was introduced but was previously
undocumented.
No functional changes to verifier behavior - nullable buffer/size pairs
continue to work exactly as before.
Acked-by: Eduard Zingerman <eddyz87@gmail.com>
Signed-off-by: Puranjay Mohan <puranjay@kernel.org>
Link: https://lore.kernel.org/r/20260102221513.1961781-1-puranjay@kernel.org
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
When arena allocations were converted from bpf_map_alloc_pages() to
kmalloc_nolock() to support non-sleepable contexts, memcg accounting was
inadvertently lost. This commit restores proper memory accounting for
all arena-related allocations.
All arena related allocations are accounted into memcg of the process
that created bpf_arena.
Signed-off-by: Puranjay Mohan <puranjay@kernel.org>
Link: https://lore.kernel.org/r/20260102200230.25168-3-puranjay@kernel.org
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Introduce bpf_map_memcg_enter() and bpf_map_memcg_exit() helpers to
reduce code duplication in memcg context management.
bpf_map_memcg_enter() gets the memcg from the map, sets it as active,
and returns both the previous and the now active memcg.
bpf_map_memcg_exit() restores the previous active memcg and releases the
reference obtained during enter.
Signed-off-by: Puranjay Mohan <puranjay@kernel.org>
Link: https://lore.kernel.org/r/20260102200230.25168-2-puranjay@kernel.org
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Now that KF_TRUSTED_ARGS is the default for all kfuncs, remove the
explicit KF_TRUSTED_ARGS flag from all kfunc definitions and remove the
flag itself.
Acked-by: Eduard Zingerman <eddyz87@gmail.com>
Reviewed-by: Emil Tsalapatis <emil@etsalapatis.com>
Signed-off-by: Puranjay Mohan <puranjay@kernel.org>
Link: https://lore.kernel.org/r/20260102180038.2708325-3-puranjay@kernel.org
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Change the verifier to make trusted args the default requirement for
all kfuncs by removing is_kfunc_trusted_args() assuming it be to always
return true.
This works because:
1. Context pointers (xdp_md, __sk_buff, etc.) are handled through their
own KF_ARG_PTR_TO_CTX case label and bypass the trusted check
2. Struct_ops callback arguments are already marked as PTR_TRUSTED during
initialization and pass is_trusted_reg()
3. KF_RCU kfuncs are handled separately via is_kfunc_rcu() checks at
call sites (always checked with || alongside is_kfunc_trusted_args)
This simple change makes all kfuncs require trusted args by default
while maintaining correct behavior for all existing special cases.
Note: This change means kfuncs that previously accepted NULL pointers
without KF_TRUSTED_ARGS will now reject NULL at verification time.
Several netfilter kfuncs are affected: bpf_xdp_ct_lookup(),
bpf_skb_ct_lookup(), bpf_xdp_ct_alloc(), and bpf_skb_ct_alloc() all
accept NULL for their bpf_tuple and opts parameters internally (checked
in __bpf_nf_ct_lookup), but after this change the verifier rejects NULL
before the kfunc is even called. This is acceptable because these kfuncs
don't work with NULL parameters in their proper usage. Now they will be
rejected rather than returning an error, which shouldn't make a
difference to BPF programs that were using these kfuncs properly.
Acked-by: Eduard Zingerman <eddyz87@gmail.com>
Reviewed-by: Emil Tsalapatis <emil@etsalapatis.com>
Signed-off-by: Puranjay Mohan <puranjay@kernel.org>
Link: https://lore.kernel.org/r/20260102180038.2708325-2-puranjay@kernel.org
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Within an iterator or callback based loop, it should be safe to prune
the current state if the old state stack slot is marked as
STACK_INVALID or STACK_MISC:
- either all branches of the old state lead to a program exit;
- or some branch of the old state leads the current state.
This is the same logic as applied in non-loop cases when
states_equal() is called in NOT_EXACT mode.
The test case that exercises stacksafe() and demonstrates the
difference in verification performance is included in the next patch.
I'm not sure if it is possible to prepare a test case that exercises
regsafe(); it appears that the compute_live_registers() pass makes
this impossible.
Nevertheless, for code readability reasons, I think that stacksafe()
and regsafe() should handle STACK_INVALID / NOT_INIT symmetrically.
Hence, this commit changes both functions.
Signed-off-by: Eduard Zingerman <eddyz87@gmail.com>
Link: https://lore.kernel.org/r/20251230-loop-stack-misc-pruning-v1-1-585cfd6cec51@gmail.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Calls like bpf_loop() or bpf_for_each_map_elem() introduce loops that
are not explicitly present in the control-flow graph. The verifier
processes such calls by repeatedly interpreting the callback function
body within the same verification path (until the current state
converges with a previous state).
Such loops require a bpf_scc_visit instance in order to allow the
accumulation of the state graph backedges. Otherwise, certain
checkpoint states created within the bodies of such loops will have
incomplete precision marks.
See the next patch for an example of a program that leads to the
verifier accepting an unsafe program.
Fixes: 96c6aa4c63 ("bpf: compute SCCs in program control flow graph")
Fixes: c9e31900b5 ("bpf: propagate read/precision marks over state graph backedges")
Reported-by: Breno Leitao <leitao@debian.org>
Signed-off-by: Eduard Zingerman <eddyz87@gmail.com>
Tested-by: Breno Leitao <leitao@debian.org>
Link: https://lore.kernel.org/r/20251229-scc-for-callbacks-v1-1-ceadfe679900@gmail.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Make arena related kfuncs any context safe by the following changes:
bpf_arena_alloc_pages() and bpf_arena_reserve_pages():
Replace the usage of the mutex with a rqspinlock for range tree and use
kmalloc_nolock() wherever needed. Use free_pages_nolock() to free pages
from any context.
apply_range_set/clear_cb() with apply_to_page_range() has already made
populating the vm_area in bpf_arena_alloc_pages() any context safe.
bpf_arena_free_pages(): defer the main logic to a workqueue if it is
called from a non-sleepable context.
specialize_kfunc() is used to replace the sleepable arena_free_pages()
with bpf_arena_free_pages_non_sleepable() when the verifier detects the
call is from a non-sleepable context.
In the non-sleepable case, arena_free_pages() queues the address and the
page count to be freed to a lock-less list of struct arena_free_spans
and raises an irq_work. The irq_work handler calls schedules_work() as
it is safe to be called from irq context. arena_free_worker() (the work
queue handler) iterates these spans and clears ptes, flushes tlb, zaps
pages, and calls __free_page().
Signed-off-by: Puranjay Mohan <puranjay@kernel.org>
Link: https://lore.kernel.org/r/20251222195022.431211-4-puranjay@kernel.org
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
To make arena_alloc_pages() safe to be called from any context, replace
kvcalloc() with kmalloc_nolock() so as it doesn't sleep or take any
locks. kmalloc_nolock() returns NULL for allocations larger than
KMALLOC_MAX_CACHE_SIZE, which is (PAGE_SIZE * 2) = 8KB on systems with
4KB pages. So, round down the allocation done by kmalloc_nolock to 1024
* 8 and reuse the array in a loop.
Signed-off-by: Puranjay Mohan <puranjay@kernel.org>
Link: https://lore.kernel.org/r/20251222195022.431211-3-puranjay@kernel.org
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
vm_area_map_pages() may allocate memory while inserting pages into bpf
arena's vm_area. In order to make bpf_arena_alloc_pages() kfunc
non-sleepable change bpf arena to populate pages without
allocating memory:
- at arena creation time populate all page table levels except
the last level
- when new pages need to be inserted call apply_to_page_range() again
with apply_range_set_cb() which will only set_pte_at() those pages and
will not allocate memory.
- when freeing pages call apply_to_existing_page_range with
apply_range_clear_cb() to clear the pte for the page to be removed. This
doesn't free intermediate page table levels.
Signed-off-by: Puranjay Mohan <puranjay@kernel.org>
Link: https://lore.kernel.org/r/20251222195022.431211-2-puranjay@kernel.org
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
The -EEXIST error code is reserved by the module loading infrastructure
to indicate that a module is already loaded. When a module's init
function returns -EEXIST, userspace tools like kmod interpret this as
"module already loaded" and treat the operation as successful, returning
0 to the user even though the module initialization actually failed.
This follows the precedent set by commit 54416fd767 ("netfilter:
conntrack: helper: Replace -EEXIST by -EBUSY") which fixed the same
issue in nf_conntrack_helper_register().
This affects bpf_crypto_skcipher module. While the configuration
required to build it as a module is unlikely in practice, it is
technically possible, so fix it for correctness.
Signed-off-by: Daniel Gomez <da.gomez@samsung.com>
Acked-by: Vadim Fedorenko <vadim.fedorenko@linux.dev>
Link: https://lore.kernel.org/r/20251220-dev-module-init-eexists-bpf-v1-1-7f186663dbe7@samsung.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Associate raw tracepoint program type with the kfunc tracing hook. This
allows calling kfuncs from raw_tp programs.
Signed-off-by: Puranjay Mohan <puranjay@kernel.org>
Acked-by: Yonghong Song <yonghong.song@linux.dev>
Link: https://lore.kernel.org/r/20251222133250.1890587-2-puranjay@kernel.org
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
As reported in [0], anonymous memory mappings are not backed by a
struct file instance. Consequently, the struct file pointer passed to
the security_mmap_file() LSM hook is NULL in such cases.
The BPF verifier is currently unaware of this, allowing BPF LSM
programs to dereference this struct file pointer without needing to
perform an explicit NULL check. This leads to potential NULL pointer
dereference and a kernel crash.
Add a strong override for bpf_lsm_mmap_file() which annotates the
struct file pointer parameter with the __nullable suffix. This
explicitly informs the BPF verifier that this pointer (PTR_MAYBE_NULL)
can be NULL, forcing BPF LSM programs to perform a check on it before
dereferencing it.
[0] https://lore.kernel.org/bpf/5e460d3c.4c3e9.19adde547d8.Coremail.kaiyanm@hust.edu.cn/
Reported-by: Kaiyan Mei <M202472210@hust.edu.cn>
Reported-by: Yinhao Hu <dddddd@hust.edu.cn>
Reviewed-by: Dongliang Mu <dzm91@hust.edu.cn>
Closes: https://lore.kernel.org/bpf/5e460d3c.4c3e9.19adde547d8.Coremail.kaiyanm@hust.edu.cn/
Signed-off-by: Matt Bobrowski <mattbobrowski@google.com>
Acked-by: Song Liu <song@kernel.org>
Link: https://lore.kernel.org/r/20251216133000.3690723-1-mattbobrowski@google.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
BPF programs detect recursion using a per-CPU 'active' flag in struct
bpf_prog. The trampoline currently sets/clears this flag with atomic
operations.
On some arm64 platforms (e.g., Neoverse V2 with LSE), per-CPU atomic
operations are relatively slow. Unlike x86_64 - where per-CPU updates
can avoid cross-core atomicity, arm64 LSE atomics are always atomic
across all cores, which is unnecessary overhead for strictly per-CPU
state.
This patch removes atomics from the recursion detection path on arm64 by
changing 'active' to a per-CPU array of four u8 counters, one per
context: {NMI, hard-irq, soft-irq, normal}. The running context uses a
non-atomic increment/decrement on its element. After increment,
recursion is detected by reading the array as a u32 and verifying that
only the expected element changed; any change in another element
indicates inter-context recursion, and a value > 1 in the same element
indicates same-context recursion.
For example, starting from {0,0,0,0}, a normal-context trigger changes
the array to {0,0,0,1}. If an NMI arrives on the same CPU and triggers
the program, the array becomes {1,0,0,1}. When the NMI context checks
the u32 against the expected mask for normal (0x00000001), it observes
0x01000001 and correctly reports recursion. Same-context recursion is
detected analogously.
Acked-by: Yonghong Song <yonghong.song@linux.dev>
Signed-off-by: Puranjay Mohan <puranjay@kernel.org>
Link: https://lore.kernel.org/r/20251219184422.2899902-3-puranjay@kernel.org
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
BPF programs detect recursion by doing atomic inc/dec on a per-cpu
active counter from the trampoline. Create two helpers for operations on
this active counter, this makes it easy to changes the recursion
detection logic in future.
This commit makes no functional changes.
Acked-by: Yonghong Song <yonghong.song@linux.dev>
Signed-off-by: Puranjay Mohan <puranjay@kernel.org>
Link: https://lore.kernel.org/r/20251219184422.2899902-2-puranjay@kernel.org
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
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Merge tag 'bpf-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/bpf/bpf
Pull bpf fixes from Alexei Starovoitov:
- Fix BPF builds due to -fms-extensions. selftests (Alexei
Starovoitov), bpftool (Quentin Monnet).
- Fix build of net/smc when CONFIG_BPF_SYSCALL=y, but CONFIG_BPF_JIT=n
(Geert Uytterhoeven)
- Fix livepatch/BPF interaction and support reliable unwinding through
BPF stack frames (Josh Poimboeuf)
- Do not audit capability check in arm64 JIT (Ondrej Mosnacek)
- Fix truncated dmabuf BPF iterator reads (T.J. Mercier)
- Fix verifier assumptions of bpf_d_path's output buffer (Shuran Liu)
- Fix warnings in libbpf when built with -Wdiscarded-qualifiers under
C23 (Mikhail Gavrilov)
* tag 'bpf-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/bpf/bpf:
selftests/bpf: add regression test for bpf_d_path()
bpf: Fix verifier assumptions of bpf_d_path's output buffer
selftests/bpf: Add test for truncated dmabuf_iter reads
bpf: Fix truncated dmabuf iterator reads
x86/unwind/orc: Support reliable unwinding through BPF stack frames
bpf: Add bpf_has_frame_pointer()
bpf, arm64: Do not audit capability check in do_jit()
libbpf: Fix -Wdiscarded-qualifiers under C23
bpftool: Fix build warnings due to MS extensions
net: smc: SMC_HS_CTRL_BPF should depend on BPF_JIT
selftests/bpf: Add -fms-extensions to bpf build flags
The verifier currently limits direct offsets into a map to 512MiB
to avoid overflow during pointer arithmetic. However, this prevents
arena maps from using direct addressing instructions to access data
at the end of > 512MiB arena maps. This is necessary when moving
arena globals to the end of the arena instead of the front.
Refactor the verifier code to remove the offset calculation during
direct value access calculations. This is possible because the only
two map types that implement .map_direct_value_addr() are arrays and
arenas, and they both do their own internal checks to ensure the
offset is within bounds.
Adjust selftests that expect the old error. These tests still fail
because the verifier identifies the access as out of bounds for the
map, so change them to expect an "invalid access to map value pointer"
error instead.
Signed-off-by: Emil Tsalapatis <emil@etsalapatis.com>
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Link: https://lore.kernel.org/bpf/20251216173325.98465-3-emil@etsalapatis.com
Commit af65320948 ("bpf: Bump iter seq size to support BTF
representation of large data structures") increased the fixed buffer
size from PAGE_SIZE to PAGE_SIZE << 3, but the docs for the function
didn't get updated at the same time. Update them.
Signed-off-by: T.J. Mercier <tjmercier@google.com>
Acked-by: Yonghong Song <yonghong.song@linux.dev>
Link: https://lore.kernel.org/r/20251207091005.2829703-1-tjmercier@google.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
This patch improves the verifier to correctly compute bounds for
sign extension compiler pattern composed of left shift by 32bits
followed by a sign right shift by 32bits. Pattern in the verifier was
limitted to positive value bounds and would reset bound computation for
negative values. New code allows both positive and negative values for
sign extension without compromising bound computation and verifier to
pass.
This change is required by GCC which generate such pattern, and was
detected in the context of systemd, as described in the following GCC
bugzilla: https://gcc.gnu.org/bugzilla/show_bug.cgi?id=119731
Three new tests were added in verifier_subreg.c.
Signed-off-by: Cupertino Miranda <cupertino.miranda@oracle.com>
Signed-off-by: Andrew Pinski <andrew.pinski@oss.qualcomm.com>
Acked-by: Eduard Zingerman <eddyz87@gmail.com>
Cc: David Faust <david.faust@oracle.com>
Cc: Jose Marchesi <jose.marchesi@oracle.com>
Cc: Elena Zannoni <elena.zannoni@oracle.com>
Link: https://lore.kernel.org/r/20251202180220.11128-2-cupertino.miranda@oracle.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
After commit 9216477449 ("bpf: cpumap: Add the possibility to attach
an eBPF program to cpumap"), __cpu_map_entry_alloc() may fail with
errors other than -ENOMEM, such as -EBADF or -EINVAL.
However, __cpu_map_entry_alloc() returns NULL on all failures, and
cpu_map_update_elem() unconditionally converts this NULL into -ENOMEM.
As a result, user space always receives -ENOMEM regardless of the actual
underlying error.
Examples of unexpected behavior:
- Nonexistent fd : -ENOMEM (should be -EBADF)
- Non-BPF fd : -ENOMEM (should be -EINVAL)
- Bad attach type : -ENOMEM (should be -EINVAL)
Change __cpu_map_entry_alloc() to return ERR_PTR(err) instead of NULL
and have cpu_map_update_elem() propagate this error.
Signed-off-by: Kohei Enju <enjuk@amazon.com>
Reviewed-by: Toke Høiland-Jørgensen <toke@redhat.com>
Link: https://lore.kernel.org/r/20251208131449.73036-2-enjuk@amazon.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
If there is a large number (hundreds) of dmabufs allocated, the text
output generated from dmabuf_iter_seq_show can exceed common user buffer
sizes (e.g. PAGE_SIZE) necessitating multiple start/stop cycles to
iterate through all dmabufs. However the dmabuf iterator currently
returns NULL in dmabuf_iter_seq_start for all non-zero pos values, which
results in the truncation of the output before all dmabufs are handled.
After dma_buf_iter_begin / dma_buf_iter_next, the refcount of the buffer
is elevated so that the BPF iterator program can run without holding any
locks. When a stop occurs, instead of immediately dropping the reference
on the buffer, stash a pointer to the buffer in seq->priv until
either start is called or the iterator is released. This also enables
the resumption of iteration without first walking through the list of
dmabufs based on the pos value.
Fixes: 76ea955349 ("bpf: Add dmabuf iterator")
Signed-off-by: T.J. Mercier <tjmercier@google.com>
Link: https://lore.kernel.org/r/20251204000348.1413593-1-tjmercier@google.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Introduce a bpf_has_frame_pointer() helper that unwinders can call to
determine whether a given instruction pointer is within the valid frame
pointer region of a BPF JIT program or trampoline (i.e., after the
prologue, before the epilogue).
This will enable livepatch (with the ORC unwinder) to reliably unwind
through BPF JIT frames.
Acked-by: Song Liu <song@kernel.org>
Acked-and-tested-by: Andrey Grodzovsky <andrey.grodzovsky@crowdstrike.com>
Signed-off-by: Josh Poimboeuf <jpoimboe@kernel.org>
Link: https://lore.kernel.org/r/fd2bc5b4e261a680774b28f6100509fd5ebad2f0.1764818927.git.jpoimboe@kernel.org
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Reviewed-by: Jiri Olsa <jolsa@kernel.org>
Add a new BPF command BPF_PROG_ASSOC_STRUCT_OPS to allow associating
a BPF program with a struct_ops map. This command takes a file
descriptor of a struct_ops map and a BPF program and set
prog->aux->st_ops_assoc to the kdata of the struct_ops map.
The command does not accept a struct_ops program nor a non-struct_ops
map. Programs of a struct_ops map is automatically associated with the
map during map update. If a program is shared between two struct_ops
maps, prog->aux->st_ops_assoc will be poisoned to indicate that the
associated struct_ops is ambiguous. The pointer, once poisoned, cannot
be reset since we have lost track of associated struct_ops. For other
program types, the associated struct_ops map, once set, cannot be
changed later. This restriction may be lifted in the future if there is
a use case.
A kernel helper bpf_prog_get_assoc_struct_ops() can be used to retrieve
the associated struct_ops pointer. The returned pointer, if not NULL, is
guaranteed to be valid and point to a fully updated struct_ops struct.
For struct_ops program reused in multiple struct_ops map, the return
will be NULL.
prog->aux->st_ops_assoc is protected by bumping the refcount for
non-struct_ops programs and RCU for struct_ops programs. Since it would
be inefficient to track programs associated with a struct_ops map, every
non-struct_ops program will bump the refcount of the map to make sure
st_ops_assoc stays valid. For a struct_ops program, it is protected by
RCU as map_free will wait for an RCU grace period before disassociating
the program with the map. The helper must be called in BPF program
context or RCU read-side critical section.
struct_ops implementers should note that the struct_ops returned may not
be initialized nor attached yet. The struct_ops implementer will be
responsible for tracking and checking the state of the associated
struct_ops map if the use case expects an initialized or attached
struct_ops.
Signed-off-by: Amery Hung <ameryhung@gmail.com>
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Acked-by: Andrii Nakryiko <andrii@kernel.org>
Acked-by: Martin KaFai Lau <martin.lau@kernel.org>
Link: https://lore.kernel.org/bpf/20251203233748.668365-3-ameryhung@gmail.com
Allow verifier to fixup kfuncs in kernel module to support kfuncs with
__prog arguments. Currently, special kfuncs and kfuncs with __prog
arguments are kernel kfuncs. Allowing kernel module kfuncs should not
affect existing kfunc fixup as kernel module kfuncs have BTF IDs greater
than kernel kfuncs' BTF IDs.
Signed-off-by: Amery Hung <ameryhung@gmail.com>
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Acked-by: Andrii Nakryiko <andrii@kernel.org>
Link: https://lore.kernel.org/bpf/20251203233748.668365-2-ameryhung@gmail.com
dentries of created objects in dcache (and undo it when removing those).
Reference is grabbed and not released, but it's not actually _stored_
anywhere. That works, but it's hard to follow and verify; among other
things, we have no way to tell _which_ of the increments is intended
to be an unpaired one. Worse, on removal we need to decide whether
the reference had already been dropped, which can be non-trivial if
that removal is on umount and we need to figure out if this dentry is
pinned due to e.g. unlink() not done. Usually that is handled by using
kill_litter_super() as ->kill_sb(), but there are open-coded special
cases of the same (consider e.g. /proc/self).
Things get simpler if we introduce a new dentry flag (DCACHE_PERSISTENT)
marking those "leaked" dentries. Having it set claims responsibility
for +1 in refcount.
The end result this series is aiming for:
* get these unbalanced dget() and dput() replaced with new primitives that
would, in addition to adjusting refcount, set and clear persistency flag.
* instead of having kill_litter_super() mess with removing the remaining
"leaked" references (e.g. for all tmpfs files that hadn't been removed
prior to umount), have the regular shrink_dcache_for_umount() strip
DCACHE_PERSISTENT of all dentries, dropping the corresponding
reference if it had been set. After that kill_litter_super() becomes
an equivalent of kill_anon_super().
Doing that in a single step is not feasible - it would affect too many places
in too many filesystems. It has to be split into a series.
This work has really started early in 2024; quite a few preliminary pieces
have already gone into mainline. This chunk is finally getting to the
meat of that stuff - infrastructure and most of the conversions to it.
Some pieces are still sitting in the local branches, but the bulk of
that stuff is here.
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
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Merge tag 'pull-persistency' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs
Pull persistent dentry infrastructure and conversion from Al Viro:
"Some filesystems use a kinda-sorta controlled dentry refcount leak to
pin dentries of created objects in dcache (and undo it when removing
those). A reference is grabbed and not released, but it's not actually
_stored_ anywhere.
That works, but it's hard to follow and verify; among other things, we
have no way to tell _which_ of the increments is intended to be an
unpaired one. Worse, on removal we need to decide whether the
reference had already been dropped, which can be non-trivial if that
removal is on umount and we need to figure out if this dentry is
pinned due to e.g. unlink() not done. Usually that is handled by using
kill_litter_super() as ->kill_sb(), but there are open-coded special
cases of the same (consider e.g. /proc/self).
Things get simpler if we introduce a new dentry flag
(DCACHE_PERSISTENT) marking those "leaked" dentries. Having it set
claims responsibility for +1 in refcount.
The end result this series is aiming for:
- get these unbalanced dget() and dput() replaced with new primitives
that would, in addition to adjusting refcount, set and clear
persistency flag.
- instead of having kill_litter_super() mess with removing the
remaining "leaked" references (e.g. for all tmpfs files that hadn't
been removed prior to umount), have the regular
shrink_dcache_for_umount() strip DCACHE_PERSISTENT of all dentries,
dropping the corresponding reference if it had been set. After that
kill_litter_super() becomes an equivalent of kill_anon_super().
Doing that in a single step is not feasible - it would affect too many
places in too many filesystems. It has to be split into a series.
This work has really started early in 2024; quite a few preliminary
pieces have already gone into mainline. This chunk is finally getting
to the meat of that stuff - infrastructure and most of the conversions
to it.
Some pieces are still sitting in the local branches, but the bulk of
that stuff is here"
* tag 'pull-persistency' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs: (54 commits)
d_make_discardable(): warn if given a non-persistent dentry
kill securityfs_recursive_remove()
convert securityfs
get rid of kill_litter_super()
convert rust_binderfs
convert nfsctl
convert rpc_pipefs
convert hypfs
hypfs: swich hypfs_create_u64() to returning int
hypfs: switch hypfs_create_str() to returning int
hypfs: don't pin dentries twice
convert gadgetfs
gadgetfs: switch to simple_remove_by_name()
convert functionfs
functionfs: switch to simple_remove_by_name()
functionfs: fix the open/removal races
functionfs: need to cancel ->reset_work in ->kill_sb()
functionfs: don't bother with ffs->ref in ffs_data_{opened,closed}()
functionfs: don't abuse ffs_data_closed() on fs shutdown
convert selinuxfs
...
- The 10 patch series "__vmalloc()/kvmalloc() and no-block support" from
Uladzislau Rezki reworks the vmalloc() code to support non-blocking
allocations (GFP_ATOIC, GFP_NOWAIT).
- The 2 patch series "ksm: fix exec/fork inheritance" from xu xin fixes
a rare case where the KSM MMF_VM_MERGE_ANY prctl state is not inherited
across fork/exec.
- The 4 patch series "mm/zswap: misc cleanup of code and documentations"
from SeongJae Park does some light maintenance work on the zswap code.
- The 5 patch series "mm/page_owner: add debugfs files 'show_handles'
and 'show_stacks_handles'" from Mauricio Faria de Oliveira enhances the
/sys/kernel/debug/page_owner debug feature. It adds unique identifiers
to differentiate the various stack traces so that userspace monitoring
tools can better match stack traces over time.
- The 2 patch series "mm/page_alloc: pcp->batch cleanups" from Joshua
Hahn makes some minor alterations to the page allocator's per-cpu-pages
feature.
- The 2 patch series "Improve UFFDIO_MOVE scalability by removing
anon_vma lock" from Lokesh Gidra addresses a scalability issue in
userfaultfd's UFFDIO_MOVE operation.
- The 2 patch series "kasan: cleanups for kasan_enabled() checks" from
Sabyrzhan Tasbolatov performs some cleanup in the KASAN code.
- The 2 patch series "drivers/base/node: fold node register and
unregister functions" from Donet Tom cleans up the NUMA node handling
code a little.
- The 4 patch series "mm: some optimizations for prot numa" from Kefeng
Wang provides some cleanups and small optimizations to the NUMA
allocation hinting code.
- The 5 patch series "mm/page_alloc: Batch callers of
free_pcppages_bulk" from Joshua Hahn addresses long lock hold times at
boot on large machines. These were causing (harmless) softlockup
warnings.
- The 2 patch series "optimize the logic for handling dirty file folios
during reclaim" from Baolin Wang removes some now-unnecessary work from
page reclaim.
- The 10 patch series "mm/damon: allow DAMOS auto-tuned for per-memcg
per-node memory usage" from SeongJae Park enhances the DAMOS auto-tuning
feature.
- The 2 patch series "mm/damon: fixes for address alignment issues in
DAMON_LRU_SORT and DAMON_RECLAIM" from Quanmin Yan fixes DAMON_LRU_SORT
and DAMON_RECLAIM with certain userspace configuration.
- The 15 patch series "expand mmap_prepare functionality, port more
users" from Lorenzo Stoakes enhances the new(ish)
file_operations.mmap_prepare() method and ports additional callsites
from the old ->mmap() over to ->mmap_prepare().
- The 8 patch series "Fix stale IOTLB entries for kernel address space"
from Lu Baolu fixes a bug (and possible security issue on non-x86) in
the IOMMU code. In some situations the IOMMU could be left hanging onto
a stale kernel pagetable entry.
- The 4 patch series "mm/huge_memory: cleanup __split_unmapped_folio()"
from Wei Yang cleans up and optimizes the folio splitting code.
- The 5 patch series "mm, swap: misc cleanup and bugfix" from Kairui
Song implements some cleanups and a minor fix in the swap discard code.
- The 8 patch series "mm/damon: misc documentation fixups" from SeongJae
Park does as advertised.
- The 9 patch series "mm/damon: support pin-point targets removal" from
SeongJae Park permits userspace to remove a specific monitoring target
in the middle of the current targets list.
- The 2 patch series "mm: MISC follow-up patches for linux/pgalloc.h"
from Harry Yoo implements a couple of cleanups related to mm header file
inclusion.
- The 2 patch series "mm/swapfile.c: select swap devices of default
priority round robin" from Baoquan He improves the selection of swap
devices for NUMA machines.
- The 3 patch series "mm: Convert memory block states (MEM_*) macros to
enums" from Israel Batista changes the memory block labels from macros
to enums so they will appear in kernel debug info.
- The 3 patch series "ksm: perform a range-walk to jump over holes in
break_ksm" from Pedro Demarchi Gomes addresses an inefficiency when KSM
unmerges an address range.
- The 22 patch series "mm/damon/tests: fix memory bugs in kunit tests"
from SeongJae Park fixes leaks and unhandled malloc() failures in DAMON
userspace unit tests.
- The 2 patch series "some cleanups for pageout()" from Baolin Wang
cleans up a couple of minor things in the page scanner's
writeback-for-eviction code.
- The 2 patch series "mm/hugetlb: refactor sysfs/sysctl interfaces" from
Hui Zhu moves hugetlb's sysfs/sysctl handling code into a new file.
- The 9 patch series "introduce VM_MAYBE_GUARD and make it sticky" from
Lorenzo Stoakes makes the VMA guard regions available in /proc/pid/smaps
and improves the mergeability of guarded VMAs.
- The 2 patch series "mm: perform guard region install/remove under VMA
lock" from Lorenzo Stoakes reduces mmap lock contention for callers
performing VMA guard region operations.
- The 2 patch series "vma_start_write_killable" from Matthew Wilcox
starts work in permitting applications to be killed when they are
waiting on a read_lock on the VMA lock.
- The 11 patch series "mm/damon/tests: add more tests for online
parameters commit" from SeongJae Park adds additional userspace testing
of DAMON's "commit" feature.
- The 9 patch series "mm/damon: misc cleanups" from SeongJae Park does
that.
- The 2 patch series "make VM_SOFTDIRTY a sticky VMA flag" from Lorenzo
Stoakes addresses the possible loss of a VMA's VM_SOFTDIRTY flag when
that VMA is merged with another.
- The 16 patch series "mm: support device-private THP" from Balbir Singh
introduces support for Transparent Huge Page (THP) migration in zone
device-private memory.
- The 3 patch series "Optimize folio split in memory failure" from Zi
Yan optimizes folio split operations in the memory failure code.
- The 2 patch series "mm/huge_memory: Define split_type and consolidate
split support checks" from Wei Yang provides some more cleanups in the
folio splitting code.
- The 16 patch series "mm: remove is_swap_[pte, pmd]() + non-swap
entries, introduce leaf entries" from Lorenzo Stoakes cleans up our
handling of pagetable leaf entries by introducing the concept of
'software leaf entries', of type softleaf_t.
- The 4 patch series "reparent the THP split queue" from Muchun Song
reparents the THP split queue to its parent memcg. This is in
preparation for addressing the long-standing "dying memcg" problem,
wherein dead memcg's linger for too long, consuming memory resources.
- The 3 patch series "unify PMD scan results and remove redundant
cleanup" from Wei Yang does a little cleanup in the hugepage collapse
code.
- The 6 patch series "zram: introduce writeback bio batching" from
Sergey Senozhatsky improves zram writeback efficiency by introducing
batched bio writeback support.
- The 4 patch series "memcg: cleanup the memcg stats interfaces" from
Shakeel Butt cleans up our handling of the interrupt safety of some
memcg stats.
- The 4 patch series "make vmalloc gfp flags usage more apparent" from
Vishal Moola cleans up vmalloc's handling of incoming GFP flags.
- The 6 patch series "mm: Add soft-dirty and uffd-wp support for RISC-V"
from Chunyan Zhang teches soft dirty and userfaultfd write protect
tracking to use RISC-V's Svrsw60t59b extension.
- The 5 patch series "mm: swap: small fixes and comment cleanups" from
Youngjun Park fixes a small bug and cleans up some of the swap code.
- The 4 patch series "initial work on making VMA flags a bitmap" from
Lorenzo Stoakes starts work on converting the vma struct's flags to a
bitmap, so we stop running out of them, especially on 32-bit.
- The 2 patch series "mm/swapfile: fix and cleanup swap list iterations"
from Youngjun Park addresses a possible bug in the swap discard code and
cleans things up a little.
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Merge tag 'mm-stable-2025-12-03-21-26' of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm
Pull MM updates from Andrew Morton:
"__vmalloc()/kvmalloc() and no-block support" (Uladzislau Rezki)
Rework the vmalloc() code to support non-blocking allocations
(GFP_ATOIC, GFP_NOWAIT)
"ksm: fix exec/fork inheritance" (xu xin)
Fix a rare case where the KSM MMF_VM_MERGE_ANY prctl state is not
inherited across fork/exec
"mm/zswap: misc cleanup of code and documentations" (SeongJae Park)
Some light maintenance work on the zswap code
"mm/page_owner: add debugfs files 'show_handles' and 'show_stacks_handles'" (Mauricio Faria de Oliveira)
Enhance the /sys/kernel/debug/page_owner debug feature by adding
unique identifiers to differentiate the various stack traces so
that userspace monitoring tools can better match stack traces over
time
"mm/page_alloc: pcp->batch cleanups" (Joshua Hahn)
Minor alterations to the page allocator's per-cpu-pages feature
"Improve UFFDIO_MOVE scalability by removing anon_vma lock" (Lokesh Gidra)
Address a scalability issue in userfaultfd's UFFDIO_MOVE operation
"kasan: cleanups for kasan_enabled() checks" (Sabyrzhan Tasbolatov)
"drivers/base/node: fold node register and unregister functions" (Donet Tom)
Clean up the NUMA node handling code a little
"mm: some optimizations for prot numa" (Kefeng Wang)
Cleanups and small optimizations to the NUMA allocation hinting
code
"mm/page_alloc: Batch callers of free_pcppages_bulk" (Joshua Hahn)
Address long lock hold times at boot on large machines. These were
causing (harmless) softlockup warnings
"optimize the logic for handling dirty file folios during reclaim" (Baolin Wang)
Remove some now-unnecessary work from page reclaim
"mm/damon: allow DAMOS auto-tuned for per-memcg per-node memory usage" (SeongJae Park)
Enhance the DAMOS auto-tuning feature
"mm/damon: fixes for address alignment issues in DAMON_LRU_SORT and DAMON_RECLAIM" (Quanmin Yan)
Fix DAMON_LRU_SORT and DAMON_RECLAIM with certain userspace
configuration
"expand mmap_prepare functionality, port more users" (Lorenzo Stoakes)
Enhance the new(ish) file_operations.mmap_prepare() method and port
additional callsites from the old ->mmap() over to ->mmap_prepare()
"Fix stale IOTLB entries for kernel address space" (Lu Baolu)
Fix a bug (and possible security issue on non-x86) in the IOMMU
code. In some situations the IOMMU could be left hanging onto a
stale kernel pagetable entry
"mm/huge_memory: cleanup __split_unmapped_folio()" (Wei Yang)
Clean up and optimize the folio splitting code
"mm, swap: misc cleanup and bugfix" (Kairui Song)
Some cleanups and a minor fix in the swap discard code
"mm/damon: misc documentation fixups" (SeongJae Park)
"mm/damon: support pin-point targets removal" (SeongJae Park)
Permit userspace to remove a specific monitoring target in the
middle of the current targets list
"mm: MISC follow-up patches for linux/pgalloc.h" (Harry Yoo)
A couple of cleanups related to mm header file inclusion
"mm/swapfile.c: select swap devices of default priority round robin" (Baoquan He)
improve the selection of swap devices for NUMA machines
"mm: Convert memory block states (MEM_*) macros to enums" (Israel Batista)
Change the memory block labels from macros to enums so they will
appear in kernel debug info
"ksm: perform a range-walk to jump over holes in break_ksm" (Pedro Demarchi Gomes)
Address an inefficiency when KSM unmerges an address range
"mm/damon/tests: fix memory bugs in kunit tests" (SeongJae Park)
Fix leaks and unhandled malloc() failures in DAMON userspace unit
tests
"some cleanups for pageout()" (Baolin Wang)
Clean up a couple of minor things in the page scanner's
writeback-for-eviction code
"mm/hugetlb: refactor sysfs/sysctl interfaces" (Hui Zhu)
Move hugetlb's sysfs/sysctl handling code into a new file
"introduce VM_MAYBE_GUARD and make it sticky" (Lorenzo Stoakes)
Make the VMA guard regions available in /proc/pid/smaps and
improves the mergeability of guarded VMAs
"mm: perform guard region install/remove under VMA lock" (Lorenzo Stoakes)
Reduce mmap lock contention for callers performing VMA guard region
operations
"vma_start_write_killable" (Matthew Wilcox)
Start work on permitting applications to be killed when they are
waiting on a read_lock on the VMA lock
"mm/damon/tests: add more tests for online parameters commit" (SeongJae Park)
Add additional userspace testing of DAMON's "commit" feature
"mm/damon: misc cleanups" (SeongJae Park)
"make VM_SOFTDIRTY a sticky VMA flag" (Lorenzo Stoakes)
Address the possible loss of a VMA's VM_SOFTDIRTY flag when that
VMA is merged with another
"mm: support device-private THP" (Balbir Singh)
Introduce support for Transparent Huge Page (THP) migration in zone
device-private memory
"Optimize folio split in memory failure" (Zi Yan)
"mm/huge_memory: Define split_type and consolidate split support checks" (Wei Yang)
Some more cleanups in the folio splitting code
"mm: remove is_swap_[pte, pmd]() + non-swap entries, introduce leaf entries" (Lorenzo Stoakes)
Clean up our handling of pagetable leaf entries by introducing the
concept of 'software leaf entries', of type softleaf_t
"reparent the THP split queue" (Muchun Song)
Reparent the THP split queue to its parent memcg. This is in
preparation for addressing the long-standing "dying memcg" problem,
wherein dead memcg's linger for too long, consuming memory
resources
"unify PMD scan results and remove redundant cleanup" (Wei Yang)
A little cleanup in the hugepage collapse code
"zram: introduce writeback bio batching" (Sergey Senozhatsky)
Improve zram writeback efficiency by introducing batched bio
writeback support
"memcg: cleanup the memcg stats interfaces" (Shakeel Butt)
Clean up our handling of the interrupt safety of some memcg stats
"make vmalloc gfp flags usage more apparent" (Vishal Moola)
Clean up vmalloc's handling of incoming GFP flags
"mm: Add soft-dirty and uffd-wp support for RISC-V" (Chunyan Zhang)
Teach soft dirty and userfaultfd write protect tracking to use
RISC-V's Svrsw60t59b extension
"mm: swap: small fixes and comment cleanups" (Youngjun Park)
Fix a small bug and clean up some of the swap code
"initial work on making VMA flags a bitmap" (Lorenzo Stoakes)
Start work on converting the vma struct's flags to a bitmap, so we
stop running out of them, especially on 32-bit
"mm/swapfile: fix and cleanup swap list iterations" (Youngjun Park)
Address a possible bug in the swap discard code and clean things
up a little
[ This merge also reverts commit ebb9aeb980 ("vfio/nvgrace-gpu:
register device memory for poison handling") because it looks
broken to me, I've asked for clarification - Linus ]
* tag 'mm-stable-2025-12-03-21-26' of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm: (321 commits)
mm: fix vma_start_write_killable() signal handling
mm/swapfile: use plist_for_each_entry in __folio_throttle_swaprate
mm/swapfile: fix list iteration when next node is removed during discard
fs/proc/task_mmu.c: fix make_uffd_wp_huge_pte() huge pte handling
mm/kfence: add reboot notifier to disable KFENCE on shutdown
memcg: remove inc/dec_lruvec_kmem_state helpers
selftests/mm/uffd: initialize char variable to Null
mm: fix DEBUG_RODATA_TEST indentation in Kconfig
mm: introduce VMA flags bitmap type
tools/testing/vma: eliminate dependency on vma->__vm_flags
mm: simplify and rename mm flags function for clarity
mm: declare VMA flags by bit
zram: fix a spelling mistake
mm/page_alloc: optimize lowmem_reserve max lookup using its semantic monotonicity
mm/vmscan: skip increasing kswapd_failures when reclaim was boosted
pagemap: update BUDDY flag documentation
mm: swap: remove scan_swap_map_slots() references from comments
mm: swap: change swap_alloc_slow() to void
mm, swap: remove redundant comment for read_swap_cache_async
mm, swap: use SWP_SOLIDSTATE to determine if swap is rotational
...
Core & protocols
----------------
- Replace busylock at the Tx queuing layer with a lockless list. Resulting
in a 300% (4x) improvement on heavy TX workloads, sending twice the
number of packets per second, for half the cpu cycles.
- Allow constantly busy flows to migrate to a more suitable CPU/NIC
queue. Normally we perform queue re-selection when flow comes out
of idle, but under extreme circumstances the flows may be constantly
busy. Add sysctl to allow periodic rehashing even if it'd risk packet
reordering.
- Optimize the NAPI skb cache, make it larger, use it in more paths.
- Attempt returning Tx skbs to the originating CPU (like we already did
for Rx skbs).
- Various data structure layout and prefetch optimizations from Eric.
- Remove ktime_get() from the recvmsg() fast path, ktime_get() is sadly
quite expensive on recent AMD machines.
- Extend threaded NAPI polling to allow the kthread busy poll for packets.
- Make MPTCP use Rx backlog processing. This lowers the lock pressure,
improving the Rx performance.
- Support memcg accounting of MPTCP socket memory.
- Allow admin to opt sockets out of global protocol memory accounting
(using a sysctl or BPF-based policy). The global limits are a poor fit
for modern container workloads, where limits are imposed using cgroups.
- Improve heuristics for when to kick off AF_UNIX garbage collection.
- Allow users to control TCP SACK compression, and default to 33% of RTT.
- Add tcp_rcvbuf_low_rtt sysctl to let datacenter users avoid unnecessarily
aggressive rcvbuf growth and overshot when the connection RTT is low.
- Preserve skb metadata space across skb_push / skb_pull operations.
- Support for IPIP encapsulation in the nftables flowtable offload.
- Support appending IP interface information to ICMP messages (RFC 5837).
- Support setting max record size in TLS (RFC 8449).
- Remove taking rtnl_lock from RTM_GETNEIGHTBL and RTM_SETNEIGHTBL.
- Use a dedicated lock (and RCU) in MPLS, instead of rtnl_lock.
- Let users configure the number of write buffers in SMC.
- Add new struct sockaddr_unsized for sockaddr of unknown length,
from Kees.
- Some conversions away from the crypto_ahash API, from Eric Biggers.
- Some preparations for slimming down struct page.
- YAML Netlink protocol spec for WireGuard.
- Add a tool on top of YAML Netlink specs/lib for reporting commonly
computed derived statistics and summarized system state.
Driver API
----------
- Add CAN XL support to the CAN Netlink interface.
- Add uAPI for reporting PHY Mean Square Error (MSE) diagnostics,
as defined by the OPEN Alliance's "Advanced diagnostic features
for 100BASE-T1 automotive Ethernet PHYs" specification.
- Add DPLL phase-adjust-gran pin attribute (and implement it in zl3073x).
- Refactor xfrm_input lock to reduce contention when NIC offloads IPsec
and performs RSS.
- Add info to devlink params whether the current setting is the default
or a user override. Allow resetting back to default.
- Add standard device stats for PSP crypto offload.
- Leverage DSA frame broadcast to implement simple HSR frame duplication
for a lot of switches without dedicated HSR offload.
- Add uAPI defines for 1.6Tbps link modes.
Device drivers
--------------
- Add Motorcomm YT921x gigabit Ethernet switch support.
- Add MUCSE driver for N500/N210 1GbE NIC series.
- Convert drivers to support dedicated ops for timestamping control,
and away from the direct IOCTL handling. While at it support GET
operations for PHY timestamping.
- Add (and convert most drivers to) a dedicated ethtool callback
for reading the Rx ring count.
- Significant refactoring efforts in the STMMAC driver, which supports
Synopsys turn-key MAC IP integrated into a ton of SoCs.
- Ethernet high-speed NICs:
- Broadcom (bnxt):
- support PPS in/out on all pins
- Intel (100G, ice, idpf):
- ice: implement standard ethtool and timestamping stats
- i40e: support setting the max number of MAC addresses per VF
- iavf: support RSS of GTP tunnels for 5G and LTE deployments
- nVidia/Mellanox (mlx5):
- reduce downtime on interface reconfiguration
- disable being an XDP redirect target by default (same as other
drivers) to avoid wasting resources if feature is unused
- Meta (fbnic):
- add support for Linux-managed PCS on 25G, 50G, and 100G links
- Wangxun:
- support Rx descriptor merge, and Tx head writeback
- support Rx coalescing offload
- support 25G SPF and 40G QSFP modules
- Ethernet virtual:
- Google (gve):
- allow ethtool to configure rx_buf_len
- implement XDP HW RX Timestamping support for DQ descriptor format
- Microsoft vNIC (mana):
- support HW link state events
- handle hardware recovery events when probing the device
- Ethernet NICs consumer, and embedded:
- usbnet: add support for Byte Queue Limits (BQL)
- AMD (amd-xgbe):
- add device selftests
- NXP (enetc):
- add i.MX94 support
- Broadcom integrated MACs (bcmgenet, bcmasp):
- bcmasp: add support for PHY-based Wake-on-LAN
- Broadcom switches (b53):
- support port isolation
- support BCM5389/97/98 and BCM63XX ARL formats
- Lantiq/MaxLinear switches:
- support bridge FDB entries on the CPU port
- use regmap for register access
- allow user to enable/disable learning
- support Energy Efficient Ethernet
- support configuring RMII clock delays
- add tagging driver for MaxLinear GSW1xx switches
- Synopsys (stmmac):
- support using the HW clock in free running mode
- add Eswin EIC7700 support
- add Rockchip RK3506 support
- add Altera Agilex5 support
- Cadence (macb):
- cleanup and consolidate descriptor and DMA address handling
- add EyeQ5 support
- TI:
- icssg-prueth: support AF_XDP
- Airoha access points:
- add missing Ethernet stats and link state callback
- add AN7583 support
- support out-of-order Tx completion processing
- Power over Ethernet:
- pd692x0: preserve PSE configuration across reboots
- add support for TPS23881B devices
- Ethernet PHYs:
- Open Alliance OATC14 10BASE-T1S PHY cable diagnostic support
- Support 50G SerDes and 100G interfaces in Linux-managed PHYs
- micrel:
- support for non PTP SKUs of lan8814
- enable in-band auto-negotiation on lan8814
- realtek:
- cable testing support on RTL8224
- interrupt support on RTL8221B
- motorcomm: support for PHY LEDs on YT853
- microchip: support for LAN867X Rev.D0 PHYs w/ SQI and cable diag
- mscc: support for PHY LED control
- CAN drivers:
- m_can: add support for optional reset and system wake up
- remove can_change_mtu() obsoleted by core handling
- mcp251xfd: support GPIO controller functionality
- Bluetooth:
- add initial support for PASTa
- WiFi:
- split ieee80211.h file, it's way too big
- improvements in VHT radiotap reporting, S1G, Channel Switch
Announcement handling, rate tracking in mesh networks
- improve multi-radio monitor mode support, and add a cfg80211 debugfs
interface for it
- HT action frame handling on 6 GHz
- initial chanctx work towards NAN
- MU-MIMO sniffer improvements
- WiFi drivers:
- RealTek (rtw89):
- support USB devices RTL8852AU and RTL8852CU
- initial work for RTL8922DE
- improved injection support
- Intel:
- iwlwifi: new sniffer API support
- MediaTek (mt76):
- WED support for >32-bit DMA
- airoha NPU support
- regdomain improvements
- continued WiFi7/MLO work
- Qualcomm/Atheros:
- ath10k: factory test support
- ath11k: TX power insertion support
- ath12k: BSS color change support
- ath12k: statistics improvements
- brcmfmac: Acer A1 840 tablet quirk
- rtl8xxxu: 40 MHz connection fixes/support
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
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Merge tag 'net-next-6.19' of git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net-next
Pull networking updates from Jakub Kicinski:
"Core & protocols:
- Replace busylock at the Tx queuing layer with a lockless list.
Resulting in a 300% (4x) improvement on heavy TX workloads, sending
twice the number of packets per second, for half the cpu cycles.
- Allow constantly busy flows to migrate to a more suitable CPU/NIC
queue.
Normally we perform queue re-selection when flow comes out of idle,
but under extreme circumstances the flows may be constantly busy.
Add sysctl to allow periodic rehashing even if it'd risk packet
reordering.
- Optimize the NAPI skb cache, make it larger, use it in more paths.
- Attempt returning Tx skbs to the originating CPU (like we already
did for Rx skbs).
- Various data structure layout and prefetch optimizations from Eric.
- Remove ktime_get() from the recvmsg() fast path, ktime_get() is
sadly quite expensive on recent AMD machines.
- Extend threaded NAPI polling to allow the kthread busy poll for
packets.
- Make MPTCP use Rx backlog processing. This lowers the lock
pressure, improving the Rx performance.
- Support memcg accounting of MPTCP socket memory.
- Allow admin to opt sockets out of global protocol memory accounting
(using a sysctl or BPF-based policy). The global limits are a poor
fit for modern container workloads, where limits are imposed using
cgroups.
- Improve heuristics for when to kick off AF_UNIX garbage collection.
- Allow users to control TCP SACK compression, and default to 33% of
RTT.
- Add tcp_rcvbuf_low_rtt sysctl to let datacenter users avoid
unnecessarily aggressive rcvbuf growth and overshot when the
connection RTT is low.
- Preserve skb metadata space across skb_push / skb_pull operations.
- Support for IPIP encapsulation in the nftables flowtable offload.
- Support appending IP interface information to ICMP messages (RFC
5837).
- Support setting max record size in TLS (RFC 8449).
- Remove taking rtnl_lock from RTM_GETNEIGHTBL and RTM_SETNEIGHTBL.
- Use a dedicated lock (and RCU) in MPLS, instead of rtnl_lock.
- Let users configure the number of write buffers in SMC.
- Add new struct sockaddr_unsized for sockaddr of unknown length,
from Kees.
- Some conversions away from the crypto_ahash API, from Eric Biggers.
- Some preparations for slimming down struct page.
- YAML Netlink protocol spec for WireGuard.
- Add a tool on top of YAML Netlink specs/lib for reporting commonly
computed derived statistics and summarized system state.
Driver API:
- Add CAN XL support to the CAN Netlink interface.
- Add uAPI for reporting PHY Mean Square Error (MSE) diagnostics, as
defined by the OPEN Alliance's "Advanced diagnostic features for
100BASE-T1 automotive Ethernet PHYs" specification.
- Add DPLL phase-adjust-gran pin attribute (and implement it in
zl3073x).
- Refactor xfrm_input lock to reduce contention when NIC offloads
IPsec and performs RSS.
- Add info to devlink params whether the current setting is the
default or a user override. Allow resetting back to default.
- Add standard device stats for PSP crypto offload.
- Leverage DSA frame broadcast to implement simple HSR frame
duplication for a lot of switches without dedicated HSR offload.
- Add uAPI defines for 1.6Tbps link modes.
Device drivers:
- Add Motorcomm YT921x gigabit Ethernet switch support.
- Add MUCSE driver for N500/N210 1GbE NIC series.
- Convert drivers to support dedicated ops for timestamping control,
and away from the direct IOCTL handling. While at it support GET
operations for PHY timestamping.
- Add (and convert most drivers to) a dedicated ethtool callback for
reading the Rx ring count.
- Significant refactoring efforts in the STMMAC driver, which
supports Synopsys turn-key MAC IP integrated into a ton of SoCs.
- Ethernet high-speed NICs:
- Broadcom (bnxt):
- support PPS in/out on all pins
- Intel (100G, ice, idpf):
- ice: implement standard ethtool and timestamping stats
- i40e: support setting the max number of MAC addresses per VF
- iavf: support RSS of GTP tunnels for 5G and LTE deployments
- nVidia/Mellanox (mlx5):
- reduce downtime on interface reconfiguration
- disable being an XDP redirect target by default (same as
other drivers) to avoid wasting resources if feature is
unused
- Meta (fbnic):
- add support for Linux-managed PCS on 25G, 50G, and 100G links
- Wangxun:
- support Rx descriptor merge, and Tx head writeback
- support Rx coalescing offload
- support 25G SPF and 40G QSFP modules
- Ethernet virtual:
- Google (gve):
- allow ethtool to configure rx_buf_len
- implement XDP HW RX Timestamping support for DQ descriptor
format
- Microsoft vNIC (mana):
- support HW link state events
- handle hardware recovery events when probing the device
- Ethernet NICs consumer, and embedded:
- usbnet: add support for Byte Queue Limits (BQL)
- AMD (amd-xgbe):
- add device selftests
- NXP (enetc):
- add i.MX94 support
- Broadcom integrated MACs (bcmgenet, bcmasp):
- bcmasp: add support for PHY-based Wake-on-LAN
- Broadcom switches (b53):
- support port isolation
- support BCM5389/97/98 and BCM63XX ARL formats
- Lantiq/MaxLinear switches:
- support bridge FDB entries on the CPU port
- use regmap for register access
- allow user to enable/disable learning
- support Energy Efficient Ethernet
- support configuring RMII clock delays
- add tagging driver for MaxLinear GSW1xx switches
- Synopsys (stmmac):
- support using the HW clock in free running mode
- add Eswin EIC7700 support
- add Rockchip RK3506 support
- add Altera Agilex5 support
- Cadence (macb):
- cleanup and consolidate descriptor and DMA address handling
- add EyeQ5 support
- TI:
- icssg-prueth: support AF_XDP
- Airoha access points:
- add missing Ethernet stats and link state callback
- add AN7583 support
- support out-of-order Tx completion processing
- Power over Ethernet:
- pd692x0: preserve PSE configuration across reboots
- add support for TPS23881B devices
- Ethernet PHYs:
- Open Alliance OATC14 10BASE-T1S PHY cable diagnostic support
- Support 50G SerDes and 100G interfaces in Linux-managed PHYs
- micrel:
- support for non PTP SKUs of lan8814
- enable in-band auto-negotiation on lan8814
- realtek:
- cable testing support on RTL8224
- interrupt support on RTL8221B
- motorcomm: support for PHY LEDs on YT853
- microchip: support for LAN867X Rev.D0 PHYs w/ SQI and cable diag
- mscc: support for PHY LED control
- CAN drivers:
- m_can: add support for optional reset and system wake up
- remove can_change_mtu() obsoleted by core handling
- mcp251xfd: support GPIO controller functionality
- Bluetooth:
- add initial support for PASTa
- WiFi:
- split ieee80211.h file, it's way too big
- improvements in VHT radiotap reporting, S1G, Channel Switch
Announcement handling, rate tracking in mesh networks
- improve multi-radio monitor mode support, and add a cfg80211
debugfs interface for it
- HT action frame handling on 6 GHz
- initial chanctx work towards NAN
- MU-MIMO sniffer improvements
- WiFi drivers:
- RealTek (rtw89):
- support USB devices RTL8852AU and RTL8852CU
- initial work for RTL8922DE
- improved injection support
- Intel:
- iwlwifi: new sniffer API support
- MediaTek (mt76):
- WED support for >32-bit DMA
- airoha NPU support
- regdomain improvements
- continued WiFi7/MLO work
- Qualcomm/Atheros:
- ath10k: factory test support
- ath11k: TX power insertion support
- ath12k: BSS color change support
- ath12k: statistics improvements
- brcmfmac: Acer A1 840 tablet quirk
- rtl8xxxu: 40 MHz connection fixes/support"
* tag 'net-next-6.19' of git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net-next: (1381 commits)
net: page_pool: sanitise allocation order
net: page pool: xa init with destroy on pp init
net/mlx5e: Support XDP target xmit with dummy program
net/mlx5e: Update XDP features in switch channels
selftests/tc-testing: Test CAKE scheduler when enqueue drops packets
net/sched: sch_cake: Fix incorrect qlen reduction in cake_drop
wireguard: netlink: generate netlink code
wireguard: uapi: generate header with ynl-gen
wireguard: uapi: move flag enums
wireguard: uapi: move enum wg_cmd
wireguard: netlink: add YNL specification
selftests: drv-net: Fix tolerance calculation in devlink_rate_tc_bw.py
selftests: drv-net: Fix and clarify TC bandwidth split in devlink_rate_tc_bw.py
selftests: drv-net: Set shell=True for sysfs writes in devlink_rate_tc_bw.py
selftests: drv-net: Use Iperf3Runner in devlink_rate_tc_bw.py
selftests: drv-net: introduce Iperf3Runner for measurement use cases
selftests: drv-net: Add devlink_rate_tc_bw.py to TEST_PROGS
net: ps3_gelic_net: Use napi_alloc_skb() and napi_gro_receive()
Documentation: net: dsa: mention simple HSR offload helpers
Documentation: net: dsa: mention availability of RedBox
...
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Merge tag 'bpf-next-6.19' of git://git.kernel.org/pub/scm/linux/kernel/git/bpf/bpf-next
Pull bpf updates from Alexei Starovoitov:
- Convert selftests/bpf/test_tc_edt and test_tc_tunnel from .sh to
test_progs runner (Alexis Lothoré)
- Convert selftests/bpf/test_xsk to test_progs runner (Bastien
Curutchet)
- Replace bpf memory allocator with kmalloc_nolock() in
bpf_local_storage (Amery Hung), and in bpf streams and range tree
(Puranjay Mohan)
- Introduce support for indirect jumps in BPF verifier and x86 JIT
(Anton Protopopov) and arm64 JIT (Puranjay Mohan)
- Remove runqslower bpf tool (Hoyeon Lee)
- Fix corner cases in the verifier to close several syzbot reports
(Eduard Zingerman, KaFai Wan)
- Several improvements in deadlock detection in rqspinlock (Kumar
Kartikeya Dwivedi)
- Implement "jmp" mode for BPF trampoline and corresponding
DYNAMIC_FTRACE_WITH_JMP. It improves "fexit" program type performance
from 80 M/s to 136 M/s. With Steven's Ack. (Menglong Dong)
- Add ability to test non-linear skbs in BPF_PROG_TEST_RUN (Paul
Chaignon)
- Do not let BPF_PROG_TEST_RUN emit invalid GSO types to stack (Daniel
Borkmann)
- Generalize buildid reader into bpf_dynptr (Mykyta Yatsenko)
- Optimize bpf_map_update_elem() for map-in-map types (Ritesh
Oedayrajsingh Varma)
- Introduce overwrite mode for BPF ring buffer (Xu Kuohai)
* tag 'bpf-next-6.19' of git://git.kernel.org/pub/scm/linux/kernel/git/bpf/bpf-next: (169 commits)
bpf: optimize bpf_map_update_elem() for map-in-map types
bpf: make kprobe_multi_link_prog_run always_inline
selftests/bpf: do not hardcode target rate in test_tc_edt BPF program
selftests/bpf: remove test_tc_edt.sh
selftests/bpf: integrate test_tc_edt into test_progs
selftests/bpf: rename test_tc_edt.bpf.c section to expose program type
selftests/bpf: Add success stats to rqspinlock stress test
rqspinlock: Precede non-head waiter queueing with AA check
rqspinlock: Disable spinning for trylock fallback
rqspinlock: Use trylock fallback when per-CPU rqnode is busy
rqspinlock: Perform AA checks immediately
rqspinlock: Enclose lock/unlock within lock entry acquisitions
bpf: Remove runqslower tool
selftests/bpf: Remove usage of lsm/file_alloc_security in selftest
bpf: Disable file_alloc_security hook
bpf: check for insn arrays in check_ptr_alignment
bpf: force BPF_F_RDONLY_PROG on insn array creation
bpf: Fix exclusive map memory leak
selftests/bpf: Make CS length configurable for rqspinlock stress test
selftests/bpf: Add lock wait time stats to rqspinlock stress test
...
by in_hardirq() and marked deprecated in 2020.
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Merge tag 'core-core-2025-12-03' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip
Pull core irq cleanup from Thomas Gleixner:
"Tree wide cleanup of the remaining users of in_irq() which got
replaced by in_hardirq() and marked deprecated in 2020"
* tag 'core-core-2025-12-03' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
treewide: Remove in_irq()
Callchain support:
- Add support for deferred user-space stack unwinding for
perf, enabled on x86. (Peter Zijlstra, Steven Rostedt)
- unwind_user/x86: Enable frame pointer unwinding on x86
(Josh Poimboeuf)
x86 PMU support and infrastructure:
- x86/insn: Simplify for_each_insn_prefix() (Peter Zijlstra)
- x86/insn,uprobes,alternative: Unify insn_is_nop()
(Peter Zijlstra)
Intel PMU driver:
- Large series to prepare for and implement architectural PEBS
support for Intel platforms such as Clearwater Forest (CWF)
and Panther Lake (PTL). (Dapeng Mi, Kan Liang)
- Check dynamic constraints (Kan Liang)
- Optimize PEBS extended config (Peter Zijlstra)
- cstates: Remove PC3 support from LunarLake (Zhang Rui)
- cstates: Add Pantherlake support (Zhang Rui)
- cstates: Clearwater Forest support (Zide Chen)
AMD PMU driver:
- x86/amd: Check event before enable to avoid GPF (George Kennedy)
Fixes and cleanups:
- task_work: Fix NMI race condition (Peter Zijlstra)
- perf/x86: Fix NULL event access and potential PEBS record loss
(Dapeng Mi)
- Misc other fixes and cleanups.
(Dapeng Mi, Ingo Molnar, Peter Zijlstra)
Signed-off-by: Ingo Molnar <mingo@kernel.org>
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Merge tag 'perf-core-2025-12-01' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip
Pull performance events updates from Ingo Molnar:
"Callchain support:
- Add support for deferred user-space stack unwinding for perf,
enabled on x86. (Peter Zijlstra, Steven Rostedt)
- unwind_user/x86: Enable frame pointer unwinding on x86 (Josh
Poimboeuf)
x86 PMU support and infrastructure:
- x86/insn: Simplify for_each_insn_prefix() (Peter Zijlstra)
- x86/insn,uprobes,alternative: Unify insn_is_nop() (Peter Zijlstra)
Intel PMU driver:
- Large series to prepare for and implement architectural PEBS
support for Intel platforms such as Clearwater Forest (CWF) and
Panther Lake (PTL). (Dapeng Mi, Kan Liang)
- Check dynamic constraints (Kan Liang)
- Optimize PEBS extended config (Peter Zijlstra)
- cstates:
- Remove PC3 support from LunarLake (Zhang Rui)
- Add Pantherlake support (Zhang Rui)
- Clearwater Forest support (Zide Chen)
AMD PMU driver:
- x86/amd: Check event before enable to avoid GPF (George Kennedy)
Fixes and cleanups:
- task_work: Fix NMI race condition (Peter Zijlstra)
- perf/x86: Fix NULL event access and potential PEBS record loss
(Dapeng Mi)
- Misc other fixes and cleanups (Dapeng Mi, Ingo Molnar, Peter
Zijlstra)"
* tag 'perf-core-2025-12-01' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (38 commits)
perf/x86/intel: Fix and clean up intel_pmu_drain_arch_pebs() type use
perf/x86/intel: Optimize PEBS extended config
perf/x86/intel: Check PEBS dyn_constraints
perf/x86/intel: Add a check for dynamic constraints
perf/x86/intel: Add counter group support for arch-PEBS
perf/x86/intel: Setup PEBS data configuration and enable legacy groups
perf/x86/intel: Update dyn_constraint base on PEBS event precise level
perf/x86/intel: Allocate arch-PEBS buffer and initialize PEBS_BASE MSR
perf/x86/intel: Process arch-PEBS records or record fragments
perf/x86/intel/ds: Factor out PEBS group processing code to functions
perf/x86/intel/ds: Factor out PEBS record processing code to functions
perf/x86/intel: Initialize architectural PEBS
perf/x86/intel: Correct large PEBS flag check
perf/x86/intel: Replace x86_pmu.drain_pebs calling with static call
perf/x86: Fix NULL event access and potential PEBS record loss
perf/x86: Remove redundant is_x86_event() prototype
entry,unwind/deferred: Fix unwind_reset_info() placement
unwind_user/x86: Fix arch=um build
perf: Support deferred user unwind
unwind_user/x86: Teach FP unwind about start of function
...
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Merge tag 'vfs-6.19-rc1.fd_prepare.fs' of git://git.kernel.org/pub/scm/linux/kernel/git/vfs/vfs
Pull fd prepare updates from Christian Brauner:
"This adds the FD_ADD() and FD_PREPARE() primitive. They simplify the
common pattern of get_unused_fd_flags() + create file + fd_install()
that is used extensively throughout the kernel and currently requires
cumbersome cleanup paths.
FD_ADD() - For simple cases where a file is installed immediately:
fd = FD_ADD(O_CLOEXEC, vfio_device_open_file(device));
if (fd < 0)
vfio_device_put_registration(device);
return fd;
FD_PREPARE() - For cases requiring access to the fd or file, or
additional work before publishing:
FD_PREPARE(fdf, O_CLOEXEC, sync_file->file);
if (fdf.err) {
fput(sync_file->file);
return fdf.err;
}
data.fence = fd_prepare_fd(fdf);
if (copy_to_user((void __user *)arg, &data, sizeof(data)))
return -EFAULT;
return fd_publish(fdf);
The primitives are centered around struct fd_prepare. FD_PREPARE()
encapsulates all allocation and cleanup logic and must be followed by
a call to fd_publish() which associates the fd with the file and
installs it into the caller's fdtable. If fd_publish() isn't called,
both are deallocated automatically. FD_ADD() is a shorthand that does
fd_publish() immediately and never exposes the struct to the caller.
I've implemented this in a way that it's compatible with the cleanup
infrastructure while also being usable separately. IOW, it's centered
around struct fd_prepare which is aliased to class_fd_prepare_t and so
we can make use of all the basica guard infrastructure"
* tag 'vfs-6.19-rc1.fd_prepare.fs' of git://git.kernel.org/pub/scm/linux/kernel/git/vfs/vfs: (42 commits)
io_uring: convert io_create_mock_file() to FD_PREPARE()
file: convert replace_fd() to FD_PREPARE()
vfio: convert vfio_group_ioctl_get_device_fd() to FD_ADD()
tty: convert ptm_open_peer() to FD_ADD()
ntsync: convert ntsync_obj_get_fd() to FD_PREPARE()
media: convert media_request_alloc() to FD_PREPARE()
hv: convert mshv_ioctl_create_partition() to FD_ADD()
gpio: convert linehandle_create() to FD_PREPARE()
pseries: port papr_rtas_setup_file_interface() to FD_ADD()
pseries: convert papr_platform_dump_create_handle() to FD_ADD()
spufs: convert spufs_gang_open() to FD_PREPARE()
papr-hvpipe: convert papr_hvpipe_dev_create_handle() to FD_PREPARE()
spufs: convert spufs_context_open() to FD_PREPARE()
net/socket: convert __sys_accept4_file() to FD_ADD()
net/socket: convert sock_map_fd() to FD_ADD()
net/kcm: convert kcm_ioctl() to FD_PREPARE()
net/handshake: convert handshake_nl_accept_doit() to FD_PREPARE()
secretmem: convert memfd_secret() to FD_ADD()
memfd: convert memfd_create() to FD_ADD()
bpf: convert bpf_token_create() to FD_PREPARE()
...
Updating a BPF_MAP_TYPE_HASH_OF_MAPS or BPF_MAP_TYPE_ARRAY_OF_MAPS via
bpf_map_update_elem() is very expensive.
In one of our workloads, we're inserting ~1400 maps of type
BPF_MAP_TYPE_ARRAY into a BPF_MAP_TYPE_ARRAY_OF_MAPS. This takes ~21
seconds on a single thread, with an average of ~15ms per call:
Function Name: map_update_elem
Number of calls: 1369
Total time: 21s 182ms 966µs
Maximum: 47ms 937µs
Average: 15ms 473µs
Minimum: 7µs
Profiling shows that nearly all of this time is going to synchronize_rcu(),
via maybe_wait_bpf_programs() in map_update_elem().
The call to synchronize_rcu() is done to ensure that after
bpf_map_update_elem() returns, no BPF programs are still looking at the old
value of the map, per commit 1ae80cf319 ("bpf: wait for running BPF
programs when updating map-in-map").
As discussed on the bpf mailing list, replace synchronize_rcu() with
synchronize_rcu_expedited(). This is 175x faster: it now takes an average
of 88 microseconds per call, for a total of 127 milliseconds in the same
benchmark:
Function Name: map_update_elem
Number of calls: 1439
Total time: 127ms 626µs
Maximum: 445µs
Average: 88µs
Minimum: 10µs
Link: https://lore.kernel.org/bpf/CAH6OuBR=w2kybK6u7aH_35B=Bo1PCukeMZefR=7V4Z2tJNK--Q@mail.gmail.com/
Signed-off-by: Ritesh Oedayrajsingh Varma <ritesh@superluminal.eu>
Link: https://lore.kernel.org/r/20251128000422.20462-1-ritesh@superluminal.eu
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
While previous commits sufficiently address the deadlocks, there are
still scenarios where queueing of waiters in NMIs can exacerbate the
possibility of timeouts.
Consider the case below:
CPU 0
<NMI>
res_spin_lock(A) -> becomes non-head waiter
</NMI>
lock owner in CS or pending waiter spinning
CPU 1
res_spin_lock(A) -> head waiter spinning on owner/pending bits
In such a scenario, the non-head waiter in NMI on CPU 0 will not poll
for deadlocks or timeout since it will simply queue behind previous
waiter (head on CPU 1), and also not enter the trylock fallback since
no rqspinlock queue waiter is active on CPU 0. In such a scenario, the
transaction initiated by the head waiter on CPU 1 will timeout,
signalling the NMI and ending the cyclic dependency, but it will cost
250 ms of time.
Instead, the NMI on CPU 0 could simply check for the presence of an AA
deadlock and only proceed with queueing on success. Add such a check
right before any form of queueing is initiated.
The reason the AA deadlock check is not used in conjunction with
in_nmi() is that a similar case could occur due to a reentrant path
in the owner's critical section, and unconditionally checking for AA
before entering the queueing path avoids expensive timeouts. Non-NMI
reentrancy only happens at controlled points in the slow path (with
specific tracepoints which do not impede the forward progress of a
waiter loop), or in the owner CS, while NMIs can land anywhere.
While this check is only needed for non-head waiter queueing, checking
whether we are head or not is racy without xchg_tail, and after that
point, we are already queued, hence for simplicity we must invoke the
check unconditionally.
Note that a more contrived case could still be constructed by using two
locks, and interrupting the progress of the respective owners by
non-head waiters of the other lock, in an ABBA fashion, which would
still not be covered by the current set of checks and conditions. It
would still lead to a timeout though, and not a deadlock. An ABBA check
cannot happen optimistically before the queueing, since it can be racy,
and needs to be happen continuously during the waiting period, which
would then require an unlinking step for queued NMI/reentrant waiters.
This is beyond the scope of this patch.
Signed-off-by: Kumar Kartikeya Dwivedi <memxor@gmail.com>
Link: https://lore.kernel.org/r/20251128232802.1031906-6-memxor@gmail.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
The original trylock fallback was inherited from qspinlock, and then
reused for the reentrant NMIs while the slow path is active. However,
under contention, it is very unlikely for the trylock to succeed in
taking the lock. In addition, a trylock also has no fairness guarantees,
and thus is prone to starvation issues under extreme scenarios.
The original qspinlock had no choice in terms of returning an error the
caller; if the node count was breached, it had to fall back to trylock
to attempt to take the lock. In case of rqspinlock, we do have the
option of returning to the user. Thus, simply attempt the trylock once,
and instead of spinning, return an error in case the lock cannot be
taken.
This ends up significantly reducing the time spent in the trylock
fallback, since we no longer wait for the timeout duration trying to
aimlessly acquire the lock when there's a high-probability that under
contention, it won't be available to us anyway.
Signed-off-by: Kumar Kartikeya Dwivedi <memxor@gmail.com>
Link: https://lore.kernel.org/r/20251128232802.1031906-5-memxor@gmail.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
In addition to deferring to the trylock fallback in NMIs, only do so
when an rqspinlock waiter is queued on the current CPU. This is detected
by noticing a non-zero node index. This allows NMI waiters to join the
waiter queue if it isn't interrupting an existing rqspinlock waiter, and
increase the chances of fairly obtaining the lock, performing deadlock
detection as the head, and not being starved while attempting the
trylock.
The trylock path in particular is unlikely to succeed under contention,
as it relies on the lock word becoming 0, which indicates no contention.
This means that the most likely result for NMIs attempting a trylock is
a timeout under contention if they don't hit an AA or ABBA case.
The core problem being addressed through the fixed commit was removing
the dependency edge between an NMI queue waiter and the queue waiter it
is interrupting. Whenever a circular dependency forms, and with no way
to break it (as non-head waiters don't poll for deadlocks or timeouts),
we would enter into a deadlock. A trylock either breaks such an edge by
probing for deadlocks, and finally terminating the waiting loop using a
timeout.
By excluding queueing on CPUs where the node index is non-zero for NMIs,
this sort of dependency is broken. The CPU enters the trylock path for
those cases, and falls back to deadlock checks and timeouts. However, in
other case where it doesn't interrupt the CPU in the slow path while its
queued on the lock, it can join the queue as a normal waiter, and avoid
trylock associated starvation and subsequent timeouts.
There are a few remaining cases here that matter: the NMI can still
preempt the owner in its critical section, and if it queues as a
non-head waiter, it can end up impeding the progress of the owner. While
this won't deadlock, since the head waiter will eventually signal the
NMI waiter to either stop (due to a timeout), it can still lead to long
timeouts. These gaps will be addressed in subsequent commits.
Note that while the node count detection approach is less conservative
than simply deferring NMIs to trylock, it is going to return errors
where attempts to lock B in NMI happen while waiters for lock A are in a
lower context on the same CPU. However, this only occurs when the lower
context is queued in the slow path, and the NMI attempt can proceed
without failure in all other cases. To continue to prevent AA deadlocks
(or ABBA in a similar NMI interrupting lower context pattern), we'd need
a more fleshed out algorithm to unlink NMI waiters after they queue and
detect such cases. However, all that complexity isn't appealing yet to
reduce the failure rate in the small window inside the slow path.
It is important to note that reentrancy in the slow path can also happen
through trace_contention_{begin,end}, but in those cases, unlike an NMI,
the forward progress of the head waiter (or the predecessor in general)
is not being blocked.
Fixes: 0d80e7f951 ("rqspinlock: Choose trylock fallback for NMI waiters")
Reported-by: Ritesh Oedayrajsingh Varma <ritesh@superluminal.eu>
Suggested-by: Alexei Starovoitov <ast@kernel.org>
Signed-off-by: Kumar Kartikeya Dwivedi <memxor@gmail.com>
Link: https://lore.kernel.org/r/20251128232802.1031906-4-memxor@gmail.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Currently, while we enter the check_timeout call immediately due to the
way the ts.spin is initialized, we still invoke the AA and ABBA checks
in the second invocation, and only initialize the timestamp in the first
one. Since each iteration is at least done with a 1ms delay, this can
add delays in detection of AA deadlocks, up to a ms.
Rework check_timeout() to avoid this. First, call check_deadlock_AA()
while initializing the timestamps for the wait period. This also means
that we only do it once per waiting period, instead of every invocation.
Finally, drop check_deadlock() and call check_deadlock_ABBA() directly.
To save on unnecessary ktime_get_mono_fast_ns() in case of AA deadlock,
sample the time only if it returns 0.
Signed-off-by: Kumar Kartikeya Dwivedi <memxor@gmail.com>
Link: https://lore.kernel.org/r/20251128232802.1031906-3-memxor@gmail.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Ritesh reported that timeouts occurred frequently for rqspinlock despite
reentrancy on the same lock on the same CPU in [0]. This patch closes
one of the races leading to this behavior, and reduces the frequency of
timeouts.
We currently have a tiny window between the fast-path cmpxchg and the
grabbing of the lock entry where an NMI could land, attempt the same
lock that was just acquired, and end up timing out. This is not ideal.
Instead, move the lock entry acquisition from the fast path to before
the cmpxchg, and remove the grabbing of the lock entry in the slow path,
assuming it was already taken by the fast path. The TAS fallback is
invoked directly without being preceded by the typical fast path,
therefore we must continue to grab the deadlock detection entry in that
case.
Case on lock leading to missed AA:
cmpxchg lock A
<NMI>
... rqspinlock acquisition of A
... timeout
</NMI>
grab_held_lock_entry(A)
There is a similar case when unlocking the lock. If the NMI lands
between the WRITE_ONCE and smp_store_release, it is possible that we end
up in a situation where the NMI fails to diagnose the AA condition,
leading to a timeout.
Case on unlock leading to missed AA:
WRITE_ONCE(rqh->locks[rqh->cnt - 1], NULL)
<NMI>
... rqspinlock acquisition of A
... timeout
</NMI>
smp_store_release(A->locked, 0)
The patch changes the order on unlock to smp_store_release() succeeded
by WRITE_ONCE() of NULL. This avoids the missed AA detection described
above, but may lead to a false positive if the NMI lands between these
two statements, which is acceptable (and preferred over a timeout).
The original intention of the reverse order on unlock was to prevent the
following possible misdiagnosis of an ABBA scenario:
grab entry A
lock A
grab entry B
lock B
unlock B
smp_store_release(B->locked, 0)
grab entry B
lock B
grab entry A
lock A
! <detect ABBA>
WRITE_ONCE(rqh->locks[rqh->cnt - 1], NULL)
If the store release were is after the WRITE_ONCE, the other CPU would
not observe B in the table of the CPU unlocking the lock B. However,
since the threads are obviously participating in an ABBA deadlock, it
is no longer appealing to use the order above since it may lead to a
250 ms timeout due to missed AA detection.
[0]: https://lore.kernel.org/bpf/CAH6OuBTjG+N=+GGwcpOUbeDN563oz4iVcU3rbse68egp9wj9_A@mail.gmail.com
Fixes: 0d80e7f951 ("rqspinlock: Choose trylock fallback for NMI waiters")
Reported-by: Ritesh Oedayrajsingh Varma <ritesh@superluminal.eu>
Signed-off-by: Kumar Kartikeya Dwivedi <memxor@gmail.com>
Link: https://lore.kernel.org/r/20251128232802.1031906-2-memxor@gmail.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
A use-after-free bug may be triggered by calling bpf_inode_storage_get()
in a BPF LSM program hooked to file_alloc_security. Disable the hook to
prevent this from happening.
The cause of the bug is shown in the trace below. In alloc_file(), a
file struct is first allocated through kmem_cache_alloc(). Then,
file_alloc_security hook is invoked. Since the zero initialization or
assignment of f->f_inode happen after this LSM hook, a BPF program may
get a dangeld inode pointer by walking the file struct.
alloc_file()
-> alloc_empty_file()
-> f = kmem_cache_alloc()
-> init_file()
-> security_file_alloc() // f->f_inode not init-ed yet!
-> f->f_inode = NULL;
-> file_init_path()
-> f->f_inode = path->dentry->d_inode
Reported-by: Kaiyan Mei <M202472210@hust.edu.cn>
Reported-by: Yinhao Hu <dddddd@hust.edu.cn>
Reported-by: Dongliang Mu <dzm91@hust.edu.cn>
Closes: https://lore.kernel.org/bpf/1d2d1968.47cd3.19ab9528e94.Coremail.kaiyanm@hust.edu.cn/
Signed-off-by: Amery Hung <ameryhung@gmail.com>
Link: https://lore.kernel.org/r/20251126202927.2584874-1-ameryhung@gmail.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Do not abuse the strict_alignment_once flag, and check if the map is
an instruction array inside the check_ptr_alignment() function.
Suggested-by: Alexei Starovoitov <ast@kernel.org>
Signed-off-by: Anton Protopopov <a.s.protopopov@gmail.com>
Link: https://lore.kernel.org/r/20251128063224.1305482-3-a.s.protopopov@gmail.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
The original implementation added a hack to check_mem_access()
to prevent programs from writing into insn arrays. To get rid
of this hack, enforce BPF_F_RDONLY_PROG on map creation.
Also fix the corresponding selftest, as the error message changes
with this patch.
Suggested-by: Alexei Starovoitov <ast@kernel.org>
Signed-off-by: Anton Protopopov <a.s.protopopov@gmail.com>
Link: https://lore.kernel.org/r/20251128063224.1305482-2-a.s.protopopov@gmail.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
It is to unify map flags checking for lookup_elem, update_elem,
lookup_batch and update_batch APIs.
Acked-by: Andrii Nakryiko <andrii@kernel.org>
Signed-off-by: Leon Hwang <leon.hwang@linux.dev>
Link: https://lore.kernel.org/r/20251125145857.98134-2-leon.hwang@linux.dev
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Implement the "jmp" mode for the bpf trampoline. For the ftrace_managed
case, we need only to set the FTRACE_OPS_FL_JMP on the tr->fops if "jmp"
is needed.
For the bpf poke case, we will check the origin poke type with the
"origin_flags", and current poke type with "tr->flags". The function
bpf_trampoline_update_fentry() is introduced to do the job.
The "jmp" mode will only be enabled with CONFIG_DYNAMIC_FTRACE_WITH_JMP
enabled and BPF_TRAMP_F_SHARE_IPMODIFY is not set. With
BPF_TRAMP_F_SHARE_IPMODIFY, we need to get the origin call ip from the
stack, so we can't use the "jmp" mode.
Signed-off-by: Menglong Dong <dongml2@chinatelecom.cn>
Acked-by: Steven Rostedt (Google) <rostedt@goodmis.org>
Link: https://lore.kernel.org/r/20251118123639.688444-7-dongml2@chinatelecom.cn
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
In the origin logic, the bpf_arch_text_poke() assume that the old and new
instructions have the same opcode. However, they can have different opcode
if we want to replace a "call" insn with a "jmp" insn.
Therefore, add the new function parameter "old_t" along with the "new_t",
which are used to indicate the old and new poke type. Meanwhile, adjust
the implement of bpf_arch_text_poke() for all the archs.
"BPF_MOD_NOP" is added to make the code more readable. In
bpf_arch_text_poke(), we still check if the new and old address is NULL to
determine if nop insn should be used, which I think is more safe.
Signed-off-by: Menglong Dong <dongml2@chinatelecom.cn>
Link: https://lore.kernel.org/r/20251118123639.688444-6-dongml2@chinatelecom.cn
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
In commit b4ce5923e7 ("bpf, x86: add new map type: instructions array")
env->used_map was copied to func[i]->aux->used_maps before jitting.
Clear these fields out after jitting such that pointer to freed memory
(env->used_maps is freed later) are not kept in a live data structure.
The reason why the copies were initially added is explained in
https://lore.kernel.org/bpf/20251105090410.1250500-1-a.s.protopopov@gmail.com
Suggested-by: Alexei Starovoitov <ast@kernel.org>
Fixes: b4ce5923e7 ("bpf, x86: add new map type: instructions array")
Signed-off-by: Anton Protopopov <a.s.protopopov@gmail.com>
Link: https://lore.kernel.org/r/20251124151515.2543403-1-a.s.protopopov@gmail.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Currently, nested rcu critical sections are rejected by the verifier and
rcu_lock state is managed by a boolean variable. Add support for nested
rcu critical sections by make active_rcu_locks a counter similar to
active_preempt_locks. bpf_rcu_read_lock() increments this counter and
bpf_rcu_read_unlock() decrements it, MEM_RCU -> PTR_UNTRUSTED transition
happens when active_rcu_locks drops to 0.
Signed-off-by: Puranjay Mohan <puranjay@kernel.org>
Acked-by: Eduard Zingerman <eddyz87@gmail.com>
Link: https://lore.kernel.org/r/20251117200411.25563-2-puranjay@kernel.org
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
This updates bpf_insn_successors() reflecting that control flow might
jump over the instructions between tail call and function exit, verifier
might assume that some writes to parent stack always happen, which is
not the case.
Signed-off-by: Eduard Zingerman <eddyz87@gmail.com>
Signed-off-by: Martin Teichmann <martin.teichmann@xfel.eu>
Link: https://lore.kernel.org/r/20251119160355.1160932-4-martin.teichmann@xfel.eu
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
A successful ebpf tail call does not return to the caller, but to the
caller-of-the-caller, often just finishing the ebpf program altogether.
Any restrictions that the verifier needs to take into account - notably
the fact that the tail call might have modified packet pointers - are to
be checked on the caller-of-the-caller. Checking it on the caller made
the verifier refuse perfectly fine programs that would use the packet
pointers after a tail call, which is no problem as this code is only
executed if the tail call was unsuccessful, i.e. nothing happened.
This patch simulates the behavior of a tail call in the verifier. A
conditional jump to the code after the tail call is added for the case
of an unsucessful tail call, and a return to the caller is simulated for
a successful tail call.
For the successful case we assume that the tail call returns an int,
as tail calls are currently only allowed in functions that return and
int. We always assume that the tail call modified the packet pointers,
as we do not know what the tail call did.
For the unsuccessful case we know nothing happened, so we do not need to
add new constraints.
This approach also allows to check other problems that may occur with
tail calls, namely we are now able to check that precision is properly
propagated into subprograms using tail calls, as well as checking the
live slots in such a subprogram.
Fixes: 1a4607ffba ("bpf: consider that tail calls invalidate packet pointers")
Link: https://lore.kernel.org/bpf/20251029105828.1488347-1-martin.teichmann@xfel.eu/
Signed-off-by: Martin Teichmann <martin.teichmann@xfel.eu>
Acked-by: Eduard Zingerman <eddyz87@gmail.com>
Link: https://lore.kernel.org/r/20251119160355.1160932-2-martin.teichmann@xfel.eu
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
In [1] Dan Carpenter reported that the following code makes the
Smatch static analyser unhappy:
17904 value = map->ops->map_lookup_elem(map, &i);
17905 if (!value)
17906 return -EINVAL;
--> 17907 items[i - start] = value->xlated_off;
The analyser assumes that the `value` variable may contain an error
and thus it should be properly checked before the dereference.
On practice this will never happen as array maps do not return
error values in map_lookup_elem, but to make the Smatch and other
possible analysers happy this patch adds a formal check.
Reported-by: Dan Carpenter <dan.carpenter@linaro.org>
Closes: https://lore.kernel.org/bpf/aR2BN1Ix--8tmVrN@stanley.mountain/ [1]
Fixes: 493d9e0d60 ("bpf, x86: add support for indirect jumps")
Signed-off-by: Anton Protopopov <a.s.protopopov@gmail.com>
Link: https://lore.kernel.org/r/20251119112517.1091793-1-a.s.protopopov@gmail.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Cross-merge networking fixes after downstream PR (net-6.18-rc7).
No conflicts, adjacent changes:
tools/testing/selftests/net/af_unix/Makefile
e1bb28bf13 ("selftest: af_unix: Add test for SO_PEEK_OFF.")
45a1cd8346 ("selftests: af_unix: Add tests for ECONNRESET and EOF semantics")
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Replace bpf memory allocator with kmalloc_nolock() to reduce memory
wastage due to preallocation.
In bpf_selem_free(), an selem now needs to wait for a RCU grace period
before being freed when reuse_now == true. Therefore, rcu_barrier()
should be always be called in bpf_local_storage_map_free().
In bpf_local_storage_free(), since smap->storage_ma is no longer needed
to return the memory, the function is now independent from smap.
Remove the outdated comment in bpf_local_storage_alloc(). We already
free selem after an RCU grace period in bpf_local_storage_update() when
bpf_local_storage_alloc() failed the cmpxchg since commit c0d63f3091
("bpf: Add bpf_selem_free()").
Signed-off-by: Amery Hung <ameryhung@gmail.com>
Reviewed-by: Martin KaFai Lau <martin.lau@kernel.org>
Link: https://lore.kernel.org/r/20251114201329.3275875-5-ameryhung@gmail.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Save the memory allocation method used for bpf_local_storage in the
struct explicitly so that we don't need to go through the hassle to
find out the info. When a later patch replaces BPF memory allocator
with kmalloc_noloc(), bpf_local_storage_free() will no longer need
smap->storage_ma to return the memory and completely remove the
dependency on smap in bpf_local_storage_free().
Signed-off-by: Amery Hung <ameryhung@gmail.com>
Reviewed-by: Martin KaFai Lau <martin.lau@kernel.org>
Link: https://lore.kernel.org/r/20251114201329.3275875-4-ameryhung@gmail.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Since selem already saves a pointer to smap, use it instead of an
additional argument in bpf_selem_free(). This requires moving the
SDATA(selem)->smap assignment from bpf_selem_link_map() to
bpf_selem_alloc() since bpf_selem_free() may be called without the
selem being linked to smap in bpf_local_storage_update().
Signed-off-by: Amery Hung <ameryhung@gmail.com>
Reviewed-by: Martin KaFai Lau <martin.lau@kernel.org>
Link: https://lore.kernel.org/r/20251114201329.3275875-3-ameryhung@gmail.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Since commit a96a44aba5 ("bpf: bpf_sk_storage: Fix invalid wait
context lockdep report"), {charge,uncharge}_mem are always true when
allocating a bpf_local_storage_elem or unlinking a bpf_local_storage_elem
from local storage, so drop these arguments. No functional change.
Signed-off-by: Amery Hung <ameryhung@gmail.com>
Reviewed-by: Martin KaFai Lau <martin.lau@kernel.org>
Link: https://lore.kernel.org/r/20251114201329.3275875-2-ameryhung@gmail.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Syzkaller triggers an invalid memory access issue following fault
injection in update_effective_progs. The issue can be described as
follows:
__cgroup_bpf_detach
update_effective_progs
compute_effective_progs
bpf_prog_array_alloc <-- fault inject
purge_effective_progs
/* change to dummy_bpf_prog */
array->items[index] = &dummy_bpf_prog.prog
---softirq start---
__do_softirq
...
__cgroup_bpf_run_filter_skb
__bpf_prog_run_save_cb
bpf_prog_run
stats = this_cpu_ptr(prog->stats)
/* invalid memory access */
flags = u64_stats_update_begin_irqsave(&stats->syncp)
---softirq end---
static_branch_dec(&cgroup_bpf_enabled_key[atype])
The reason is that fault injection caused update_effective_progs to fail
and then changed the original prog into dummy_bpf_prog.prog in
purge_effective_progs. Then a softirq came, and accessing the members of
dummy_bpf_prog.prog in the softirq triggers invalid mem access.
To fix it, skip updating stats when stats is NULL.
Fixes: 492ecee892 ("bpf: enable program stats")
Signed-off-by: Pu Lehui <pulehui@huawei.com>
Link: https://lore.kernel.org/r/20251115102343.2200727-1-pulehui@huaweicloud.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
mm_get_unmapped_area() is a wrapper around arch_get_unmapped_area() /
arch_get_unmapped_area_topdown(), both of which search current->mm for
some free space. Neither take an mm_struct - they implicitly operate on
current->mm.
But the wrapper takes an mm_struct and uses it to decide whether to search
bottom up or top down. All callers pass in current->mm for this, so
everything is working consistently. But it feels like an accident waiting
to happen; eventually someone will call that function with a different mm,
expecting to find free space in it, but what gets returned is free space
in the current mm.
So let's simplify by removing the parameter and have the wrapper use
current->mm to decide which end to start at. Now everything is consistent
and self-documenting.
Link: https://lkml.kernel.org/r/20251003155306.2147572-1-ryan.roberts@arm.com
Signed-off-by: Ryan Roberts <ryan.roberts@arm.com>
Acked-by: David Hildenbrand <david@redhat.com>
Reviewed-by: Oscar Salvador <osalvador@suse.de>
Reviewed-by: Dev Jain <dev.jain@arm.com>
Reviewed-by: Anshuman Khandual <anshuman.khandual@arm.com>
Reviewed-by: Lorenzo Stoakes <lorenzo.stoakes@oracle.com>
Reviewed-by: Baolin Wang <baolin.wang@linux.alibaba.com>
Cc: Liam Howlett <liam.howlett@oracle.com>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Mike Rapoport <rppt@kernel.org>
Cc: Suren Baghdasaryan <surenb@google.com>
Cc: Vlastimil Babka <vbabka@suse.cz>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
object creation goes through the normal VFS paths or approximation
thereof (user_path_create()/done_path_create() in case of bpf_obj_do_pin(),
open-coded simple_{start,done}_creating() in bpf_iter_link_pin_kernel()
at mount time), removals go entirely through the normal VFS paths (and
->unlink() is simple_unlink() there).
Enough to have bpf_dentry_finalize() use d_make_persistent() instead
of dget() and we are done.
Convert bpf_iter_link_pin_kernel() to simple_{start,done}_creating(),
while we are at it.
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
If xlated_prog_insns should not be exposed, other information
(such as func_info) still can and should be filled in.
Therefore, instead of directly terminating in this case,
continue with the normal flow.
Signed-off-by: Max Altgelt <max.altgelt@nextron-systems.com>
Link: https://lore.kernel.org/r/efd00fcec5e3e247af551632726e2a90c105fbd8.camel@nextron-systems.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Metadata about a kfunc call is added to the kfunc_tab in
add_kfunc_call() but the call instruction itself could get removed by
opt_remove_dead_code() later if it is not reachable.
If the call instruction is removed, specialize_kfunc() is never called
for it and the desc->imm in the kfunc_tab is never initialized for this
kfunc call. In this case, sort_kfunc_descs_by_imm_off(env->prog); in
do_misc_fixups() doesn't sort the table correctly.
This is a problem for s390 as its JIT uses this table to find the
addresses for kfuncs, and if this table is not sorted properly, JIT may
fail to find addresses for valid kfunc calls.
This was exposed by:
commit d869d56ca8 ("bpf: verifier: refactor kfunc specialization")
as before this commit, desc->imm was initialised in add_kfunc_call()
which happens before dead code elimination.
Move desc->imm setup down to sort_kfunc_descs_by_imm_off(), this fixes
the problem and also saves us from having the same logic in
add_kfunc_call() and specialize_kfunc().
Suggested-by: Eduard Zingerman <eddyz87@gmail.com>
Signed-off-by: Puranjay Mohan <puranjay@kernel.org>
Acked-by: Eduard Zingerman <eddyz87@gmail.com>
Link: https://lore.kernel.org/r/20251114154023.12801-1-puranjay@kernel.org
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
The error that returned by ftrace_set_filter_ip() in register_fentry() is
not handled properly. Just fix it.
Fixes: 00963a2e75 ("bpf: Support bpf_trampoline on functions with IPMODIFY (e.g. livepatch)")
Signed-off-by: Menglong Dong <dongml2@chinatelecom.cn>
Acked-by: Song Liu <song@kernel.org>
Link: https://lore.kernel.org/r/20251110120705.1553694-1-dongml2@chinatelecom.cn
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
There are a few places where log level is not checked before calling
"verbose()". This forces programs working only at
BPF_LOG_LEVEL_STATS (e.g. veristat) to allocate unnecessarily large
log buffers. Add missing checks.
Reported-by: Emil Tsalapatis <emil@etsalapatis.com>
Signed-off-by: Eduard Zingerman <eddyz87@gmail.com>
Link: https://lore.kernel.org/r/20251114200542.912386-1-eddyz87@gmail.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
bpf_try_get_buffers() returns one of multiple per-CPU buffers based on a
per-CPU nesting counter. This mechanism expects that buffers are not
endlessly acquired before being returned. migrate_disable() ensures that a
task remains on the same CPU, but it does not prevent the task from being
preempted by another task on that CPU.
Without disabled preemption, a task may be preempted while holding a
buffer, allowing another task to run on same CPU and acquire an
additional buffer. Several such preemptions can cause the per-CPU
nest counter to exceed MAX_BPRINTF_NEST_LEVEL and trigger the warning in
bpf_try_get_buffers(). Adding preempt_disable()/preempt_enable() around
buffer acquisition and release prevents this task preemption and
preserves the intended bounded nesting behavior.
Reported-by: syzbot+b0cff308140f79a9c4cb@syzkaller.appspotmail.com
Closes: https://lore.kernel.org/all/68f6a4c8.050a0220.1be48.0011.GAE@google.com/
Fixes: 4223bf833c ("bpf: Remove preempt_disable in bpf_try_get_buffers")
Suggested-by: Yonghong Song <yonghong.song@linux.dev>
Reviewed-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Signed-off-by: Sahil Chandna <chandna.sahil@gmail.com>
Link: https://lore.kernel.org/r/20251114064922.11650-1-chandna.sahil@gmail.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
The usage pattern for widen_imprecise_scalars() looks as follows:
prev_st = find_prev_entry(env, ...);
queued_st = push_stack(...);
widen_imprecise_scalars(env, prev_st, queued_st);
Where prev_st is an ancestor of the queued_st in the explored states
tree. This ancestor is not guaranteed to have same allocated stack
depth as queued_st. E.g. in the following case:
def main():
for i in 1..2:
foo(i) // same callsite, differnt param
def foo(i):
if i == 1:
use 128 bytes of stack
iterator based loop
Here, for a second 'foo' call prev_st->allocated_stack is 128,
while queued_st->allocated_stack is much smaller.
widen_imprecise_scalars() needs to take this into account and avoid
accessing bpf_verifier_state->frame[*]->stack out of bounds.
Fixes: 2793a8b015 ("bpf: exact states comparison for iterator convergence checks")
Reported-by: Emil Tsalapatis <emil@etsalapatis.com>
Signed-off-by: Eduard Zingerman <eddyz87@gmail.com>
Link: https://lore.kernel.org/r/20251114025730.772723-1-eddyz87@gmail.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
As [lru_,]percpu_hash maps support BPF_KPTR_{REF,PERCPU}, missing
calls to 'bpf_obj_free_fields()' in 'pcpu_copy_value()' could cause the
memory referenced by BPF_KPTR_{REF,PERCPU} fields to be held until the
map gets freed.
Fix this by calling 'bpf_obj_free_fields()' after
'copy_map_value[,_long]()' in 'pcpu_copy_value()'.
Fixes: 65334e64a4 ("bpf: Support kptrs in percpu hashmap and percpu LRU hashmap")
Signed-off-by: Leon Hwang <leon.hwang@linux.dev>
Acked-by: Yonghong Song <yonghong.song@linux.dev>
Link: https://lore.kernel.org/r/20251105151407.12723-2-leon.hwang@linux.dev
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Return -ETIMEDOUT whenever non-head waiters are signalled by head, and fix
oversight in commit 7bd6e5ce5b ("rqspinlock: Disable queue destruction for
deadlocks"). We no longer signal on deadlocks.
Signed-off-by: Kumar Kartikeya Dwivedi <memxor@gmail.com>
Reviewed-by: Amery Hung <ameryhung@gmail.com>
Link: https://lore.kernel.org/r/20251111013827.1853484-1-memxor@gmail.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Exports three necessary symbols for implementing struct_ops with
tristate subsystem.
To hold or release refcnt of struct_ops refcnt by inline funcs
bpf_try_module_get and bpf_module_put which use bpf_struct_ops_get(put)
conditionally.
And to copy obj name from one to the other with effective checks by
bpf_obj_name_cpy.
Signed-off-by: D. Wythe <alibuda@linux.alibaba.com>
Signed-off-by: Martin KaFai Lau <martin.lau@kernel.org>
Link: https://patch.msgid.link/20251107035632.115950-2-alibuda@linux.alibaba.com
Currently bpf_dynptr_from_skb_meta() marks the dynptr as read-only when
the skb is cloned, preventing writes to metadata.
Remove this restriction and unclone the skb head on bpf_dynptr_write() to
metadata, now that the metadata is preserved during uncloning. This makes
metadata dynptr consistent with skb dynptr, allowing writes regardless of
whether the skb is cloned.
Signed-off-by: Jakub Sitnicki <jakub@cloudflare.com>
Signed-off-by: Martin KaFai Lau <martin.lau@kernel.org>
Link: https://patch.msgid.link/20251105-skb-meta-rx-path-v4-3-5ceb08a9b37b@cloudflare.com
The range tree uses bpf_mem_alloc() that is safe to be called from all
contexts and uses a pre-allocated pool of memory to serve these
allocations.
Replace bpf_mem_alloc() with kmalloc_nolock() as it can be called safely
from all contexts and is more scalable than bpf_mem_alloc().
Remove the migrate_disable/enable pairs as they were only needed for
bpf_mem_alloc() as it does per-cpu operations, kmalloc_nolock() doesn't
need this.
Signed-off-by: Puranjay Mohan <puranjay@kernel.org>
Link: https://lore.kernel.org/r/20251106170608.4800-1-puranjay@kernel.org
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Cross-merge networking fixes after downstream PR (net-6.18-rc5).
Conflicts:
drivers/net/wireless/ath/ath12k/mac.c
9222582ec5 ("Revert "wifi: ath12k: Fix missing station power save configuration"")
6917e268c4 ("wifi: ath12k: Defer vdev bring-up until CSA finalize to avoid stale beacon")
https://lore.kernel.org/11cece9f7e36c12efd732baa5718239b1bf8c950.camel@sipsolutions.net
Adjacent changes:
drivers/net/ethernet/intel/Kconfig
b1d16f7c00 ("libie: depend on DEBUG_FS when building LIBIE_FWLOG")
93f53db9f9 ("ice: switch to Page Pool")
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Add support for a new instruction
BPF_JMP|BPF_X|BPF_JA, SRC=0, DST=Rx, off=0, imm=0
which does an indirect jump to a location stored in Rx. The register
Rx should have type PTR_TO_INSN. This new type assures that the Rx
register contains a value (or a range of values) loaded from a
correct jump table – map of type instruction array.
For example, for a C switch LLVM will generate the following code:
0: r3 = r1 # "switch (r3)"
1: if r3 > 0x13 goto +0x666 # check r3 boundaries
2: r3 <<= 0x3 # adjust to an index in array of addresses
3: r1 = 0xbeef ll # r1 is PTR_TO_MAP_VALUE, r1->map_ptr=M
5: r1 += r3 # r1 inherits boundaries from r3
6: r1 = *(u64 *)(r1 + 0x0) # r1 now has type INSN_TO_PTR
7: gotox r1 # jit will generate proper code
Here the gotox instruction corresponds to one particular map. This is
possible however to have a gotox instruction which can be loaded from
different maps, e.g.
0: r1 &= 0x1
1: r2 <<= 0x3
2: r3 = 0x0 ll # load from map M_1
4: r3 += r2
5: if r1 == 0x0 goto +0x4
6: r1 <<= 0x3
7: r3 = 0x0 ll # load from map M_2
9: r3 += r1
A: r1 = *(u64 *)(r3 + 0x0)
B: gotox r1 # jump to target loaded from M_1 or M_2
During check_cfg stage the verifier will collect all the maps which
point to inside the subprog being verified. When building the config,
the high 16 bytes of the insn_state are used, so this patch
(theoretically) supports jump tables of up to 2^16 slots.
During the later stage, in check_indirect_jump, it is checked that
the register Rx was loaded from a particular instruction array.
Signed-off-by: Anton Protopopov <a.s.protopopov@gmail.com>
Acked-by: Eduard Zingerman <eddyz87@gmail.com>
Link: https://lore.kernel.org/r/20251105090410.1250500-9-a.s.protopopov@gmail.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
When bpf_jit_harden is enabled, all constants in the BPF code are
blinded to prevent JIT spraying attacks. This happens during JIT
phase. Adjust all the related instruction arrays accordingly.
Signed-off-by: Anton Protopopov <a.s.protopopov@gmail.com>
Reviewed-by: Eduard Zingerman <eddyz87@gmail.com>
Link: https://lore.kernel.org/r/20251105090410.1250500-6-a.s.protopopov@gmail.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
On bpf(BPF_PROG_LOAD) syscall user-supplied BPF programs are
translated by the verifier into "xlated" BPF programs. During this
process the original instructions offsets might be adjusted and/or
individual instructions might be replaced by new sets of instructions,
or deleted.
Add a new BPF map type which is aimed to keep track of how, for a
given program, the original instructions were relocated during the
verification. Also, besides keeping track of the original -> xlated
mapping, make x86 JIT to build the xlated -> jitted mapping for every
instruction listed in an instruction array. This is required for every
future application of instruction arrays: static keys, indirect jumps
and indirect calls.
A map of the BPF_MAP_TYPE_INSN_ARRAY type must be created with a u32
keys and value of size 8. The values have different semantics for
userspace and for BPF space. For userspace a value consists of two
u32 values – xlated and jitted offsets. For BPF side the value is
a real pointer to a jitted instruction.
On map creation/initialization, before loading the program, each
element of the map should be initialized to point to an instruction
offset within the program. Before the program load such maps should
be made frozen. After the program verification xlated and jitted
offsets can be read via the bpf(2) syscall.
If a tracked instruction is removed by the verifier, then the xlated
offset is set to (u32)-1 which is considered to be too big for a valid
BPF program offset.
One such a map can, obviously, be used to track one and only one BPF
program. If the verification process was unsuccessful, then the same
map can be re-used to verify the program with a different log level.
However, if the program was loaded fine, then such a map, being
frozen in any case, can't be reused by other programs even after the
program release.
Example. Consider the following original and xlated programs:
Original prog: Xlated prog:
0: r1 = 0x0 0: r1 = 0
1: *(u32 *)(r10 - 0x4) = r1 1: *(u32 *)(r10 -4) = r1
2: r2 = r10 2: r2 = r10
3: r2 += -0x4 3: r2 += -4
4: r1 = 0x0 ll 4: r1 = map[id:88]
6: call 0x1 6: r1 += 272
7: r0 = *(u32 *)(r2 +0)
8: if r0 >= 0x1 goto pc+3
9: r0 <<= 3
10: r0 += r1
11: goto pc+1
12: r0 = 0
7: r6 = r0 13: r6 = r0
8: if r6 == 0x0 goto +0x2 14: if r6 == 0x0 goto pc+4
9: call 0x76 15: r0 = 0xffffffff8d2079c0
17: r0 = *(u64 *)(r0 +0)
10: *(u64 *)(r6 + 0x0) = r0 18: *(u64 *)(r6 +0) = r0
11: r0 = 0x0 19: r0 = 0x0
12: exit 20: exit
An instruction array map, containing, e.g., instructions [0,4,7,12]
will be translated by the verifier to [0,4,13,20]. A map with
index 5 (the middle of 16-byte instruction) or indexes greater than 12
(outside the program boundaries) would be rejected.
The functionality provided by this patch will be extended in consequent
patches to implement BPF Static Keys, indirect jumps, and indirect calls.
Signed-off-by: Anton Protopopov <a.s.protopopov@gmail.com>
Reviewed-by: Eduard Zingerman <eddyz87@gmail.com>
Link: https://lore.kernel.org/r/20251105090410.1250500-2-a.s.protopopov@gmail.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Change struct bpf_sock_addr_kern to use sockaddr_unsized for the "uaddr"
field instead of sockaddr. This improves type safety in the BPF cgroup
socket address filtering code.
The casting in __cgroup_bpf_run_filter_sock_addr() is updated to match the
new type, removing an unnecessary cast in the initialization and updating
the conditional assignment to use the appropriate sockaddr_unsized cast.
Additionally rename the "unspec" variable to "storage" to better align
with its usage.
No binary changes expected.
Signed-off-by: Kees Cook <kees@kernel.org>
Link: https://patch.msgid.link/20251104002617.2752303-7-kees@kernel.org
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Update BPF cgroup sockaddr filtering infrastructure to use sockaddr_unsized
consistently throughout the call chain, removing redundant explicit casts
from callers.
No binary changes expected.
Signed-off-by: Kees Cook <kees@kernel.org>
Link: https://patch.msgid.link/20251104002617.2752303-6-kees@kernel.org
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Rename bpf_stream_vprintk() to bpf_stream_vprintk_impl().
This makes bpf_stream_vprintk() follow the already established "_impl"
suffix-based naming convention for kfuncs with the bpf_prog_aux
argument provided by the verifier implicitly. This convention will be
taken advantage of with the upcoming KF_IMPLICIT_ARGS feature to
preserve backwards compatibility to BPF programs.
Acked-by: Andrii Nakryiko <andrii@kernel.org>
Signed-off-by: Mykyta Yatsenko <yatsenko@meta.com>
Link: https://lore.kernel.org/r/20251104-implv2-v3-2-4772b9ae0e06@meta.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Acked-by: Ihor Solodrai <ihor.solodrai@linux.dev>
Rename:
bpf_task_work_schedule_resume()->bpf_task_work_schedule_resume_impl()
bpf_task_work_schedule_signal()->bpf_task_work_schedule_signal_impl()
This aligns task work scheduling kfuncs with the established naming
scheme for kfuncs with the bpf_prog_aux argument provided by the
verifier implicitly. This convention will be taken advantage of with the
upcoming KF_IMPLICIT_ARGS feature to preserve backwards compatibility to
BPF programs.
Acked-by: Andrii Nakryiko <andrii@kernel.org>
Signed-off-by: Mykyta Yatsenko <yatsenko@meta.com>
Link: https://lore.kernel.org/r/20251104-implv2-v3-1-4772b9ae0e06@meta.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Acked-by: Ihor Solodrai <ihor.solodrai@linux.dev>
When conditional jumps are performed on the same scalar register
(e.g., r0 <= r0, r0 > r0, r0 < r0), the BPF verifier incorrectly
attempts to adjust the register's min/max bounds. This leads to
invalid range bounds and triggers a BUG warning.
The problematic BPF program:
0: call bpf_get_prandom_u32
1: w8 = 0x80000000
2: r0 &= r8
3: if r0 > r0 goto <exit>
The instruction 3 triggers kernel warning:
3: if r0 > r0 goto <exit>
true_reg1: range bounds violation u64=[0x1, 0x0] s64=[0x1, 0x0] u32=[0x1, 0x0] s32=[0x1, 0x0] var_off=(0x0, 0x0)
true_reg2: const tnum out of sync with range bounds u64=[0x0, 0xffffffffffffffff] s64=[0x8000000000000000, 0x7fffffffffffffff] var_off=(0x0, 0x0)
Comparing a register with itself should not change its bounds and
for most comparison operations, comparing a register with itself has
a known result (e.g., r0 == r0 is always true, r0 < r0 is always false).
Fix this by:
1. Enhance is_scalar_branch_taken() to properly handle branch direction
computation for same register comparisons across all BPF jump operations
2. Adds early return in reg_set_min_max() to avoid bounds adjustment
for unknown branch directions (e.g., BPF_JSET) on the same register
The fix ensures that unnecessary bounds adjustments are skipped, preventing
the verifier bug while maintaining correct branch direction analysis.
Reported-by: Kaiyan Mei <M202472210@hust.edu.cn>
Reported-by: Yinhao Hu <dddddd@hust.edu.cn>
Closes: https://lore.kernel.org/all/1881f0f5.300df.199f2576a01.Coremail.kaiyanm@hust.edu.cn/
Signed-off-by: KaFai Wan <kafai.wan@linux.dev>
Acked-by: Eduard Zingerman <eddyz87@gmail.com>
Link: https://lore.kernel.org/r/20251103063108.1111764-2-kafai.wan@linux.dev
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
When livepatch is attached to the same function as bpf trampoline with
a fexit program, bpf trampoline code calls register_ftrace_direct()
twice. The first time will fail with -EAGAIN, and the second time it
will succeed. This requires register_ftrace_direct() to unregister
the address on the first attempt. Otherwise, the bpf trampoline cannot
attach. Here is an easy way to reproduce this issue:
insmod samples/livepatch/livepatch-sample.ko
bpftrace -e 'fexit:cmdline_proc_show {}'
ERROR: Unable to attach probe: fexit:vmlinux:cmdline_proc_show...
Fix this by cleaning up the hash when register_ftrace_function_nolock hits
errors.
Also, move the code that resets ops->func and ops->trampoline to the error
path of register_ftrace_direct(); and add a helper function reset_direct()
in register_ftrace_direct() and unregister_ftrace_direct().
Fixes: d05cb47066 ("ftrace: Fix modification of direct_function hash while in use")
Cc: stable@vger.kernel.org # v6.6+
Reported-by: Andrey Grodzovsky <andrey.grodzovsky@crowdstrike.com>
Closes: https://lore.kernel.org/live-patching/c5058315a39d4615b333e485893345be@crowdstrike.com/
Cc: Steven Rostedt (Google) <rostedt@goodmis.org>
Cc: Masami Hiramatsu (Google) <mhiramat@kernel.org>
Acked-and-tested-by: Andrey Grodzovsky <andrey.grodzovsky@crowdstrike.com>
Signed-off-by: Song Liu <song@kernel.org>
Reviewed-by: Jiri Olsa <jolsa@kernel.org>
Link: https://lore.kernel.org/r/20251027175023.1521602-2-song@kernel.org
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Acked-by: Steven Rostedt (Google) <rostedt@goodmis.org>
BPF stream kfuncs need to be non-sleeping as they can be called from
programs running in any context, this requires a way to allocate memory
from any context. Currently, this is done by a custom per-CPU NMI-safe
bump allocation mechanism, backed by alloc_pages_nolock() and
free_pages_nolock() primitives.
As kmalloc_nolock() and kfree_nolock() primitives are available now, the
custom allocator can be removed in favor of these.
Signed-off-by: Puranjay Mohan <puranjay@kernel.org>
Acked-by: Kumar Kartikeya Dwivedi <memxor@gmail.com>
Link: https://lore.kernel.org/r/20251023161448.4263-1-puranjay@kernel.org
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Disable propagation and unwinding of the waiter queue in case the head
waiter detects a deadlock condition, but keep it enabled in case of the
timeout fallback.
Currently, when the head waiter experiences an AA deadlock, it will
signal all its successors in the queue to exit with an error. This is
not ideal for cases where the same lock is held in contexts which can
cause errors in an unrestricted fashion (e.g., BPF programs, or kernel
paths invoked through BPF programs), and core kernel logic which is
written in a correct fashion and does not expect deadlocks.
The same reasoning can be extended to ABBA situations. Depending on the
actual runtime schedule, one or both of the head waiters involved in an
ABBA situation can detect and exit directly without terminating their
waiter queue. If the ABBA situation manifests again, the waiters will
keep exiting until progress can be made, or a timeout is triggered in
case of more complicated locking dependencies.
We still preserve the queue destruction in case of timeouts, as either
the locking dependencies are too complex to be captured by AA and ABBA
heuristics, or the owner is perpetually stuck. As such, it would be
unwise to continue to apply the timeout for each new head waiter without
terminating the queue, since we may end up waiting for more than 250 ms
in aggregate with all participants in the locking transaction.
The patch itself is fairly simple; we can simply signal our successor to
become the next head waiter, and leave the queue without attempting to
acquire the lock.
With this change, the behavior for waiters in case of deadlocks
experienced by a predecessor changes. It is guaranteed that call sites
will no longer receive errors if the predecessors encounter deadlocks
and the successors do not participate in one. This should lower the
failure rate for waiters that are not doing improper locking opreations,
just because they were unlucky to queue behind a misbehaving waiter.
However, timeouts are still a possibility, hence they must be accounted
for, so users cannot rely upon errors not occuring at all.
Suggested-by: Amery Hung <ameryhung@gmail.com>
Suggested-by: Alexei Starovoitov <ast@kernel.org>
Signed-off-by: Kumar Kartikeya Dwivedi <memxor@gmail.com>
Link: https://lore.kernel.org/r/20251029181828.231529-2-memxor@gmail.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Add support for deferred userspace unwind to perf.
Where perf currently relies on in-place stack unwinding; from NMI
context and all that. This moves the userspace part of the unwind to
right before the return-to-userspace.
This has two distinct benefits, the biggest is that it moves the
unwind to a faultable context. It becomes possible to fault in debug
info (.eh_frame, SFrame etc.) that might not otherwise be readily
available. And secondly, it de-duplicates the user callchain where
multiple samples happen during the same kernel entry.
To facilitate this the perf interface is extended with a new record
type:
PERF_RECORD_CALLCHAIN_DEFERRED
and two new attribute flags:
perf_event_attr::defer_callchain - to request the user unwind be deferred
perf_event_attr::defer_output - to request PERF_RECORD_CALLCHAIN_DEFERRED records
The existing PERF_RECORD_SAMPLE callchain section gets a new
context type:
PERF_CONTEXT_USER_DEFERRED
After which will come a single entry, denoting the 'cookie' of the
deferred callchain that should be attached here, matching the 'cookie'
field of the above mentioned PERF_RECORD_CALLCHAIN_DEFERRED.
The 'defer_callchain' flag is expected on all events with
PERF_SAMPLE_CALLCHAIN. The 'defer_output' flag is expect on the event
responsible for collecting side-band events (like mmap, comm etc.).
Setting 'defer_output' on multiple events will get you duplicated
PERF_RECORD_CALLCHAIN_DEFERRED records.
Based on earlier patches by Josh and Steven.
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Link: https://patch.msgid.link/20251023150002.GR4067720@noisy.programming.kicks-ass.net
Extract the duplicated maximum allowed depth computation for stack
traces stored in BPF stacks from bpf_get_stackid() and __bpf_get_stack()
into a dedicated stack_map_calculate_max_depth() helper function.
This unifies the logic for:
- The max depth computation
- Enforcing the sysctl_perf_event_max_stack limit
No functional changes for existing code paths.
Signed-off-by: Arnaud Lecomte <contact@arnaud-lcm.com>
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Acked-by: Yonghong Song <yonghong.song@linux.dev>
Acked-by: Song Liu <song@kernel.org>
Link: https://lore.kernel.org/bpf/20251025192858.31424-1-contact@arnaud-lcm.com
File dynptr reads may sleep when the requested folios are not in
the page cache. To avoid sleeping in non-sleepable contexts while still
supporting valid sleepable use, given that dynptrs are non-sleepable by
default, enable sleeping only when bpf_dynptr_from_file() is invoked
from a sleepable context.
This change:
* Introduces a sleepable constructor: bpf_dynptr_from_file_sleepable()
* Override non-sleepable constructor with sleepable if it's always
called in sleepable context
Signed-off-by: Mykyta Yatsenko <yatsenko@meta.com>
Acked-by: Eduard Zingerman <eddyz87@gmail.com>
Link: https://lore.kernel.org/r/20251026203853.135105-10-mykyta.yatsenko5@gmail.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Move kfunc specialization (function address substitution) to later stage
of verification to support a new use case, where we need to take into
consideration whether kfunc is called in sleepable context.
Minor refactoring in add_kfunc_call(), making sure that if function
fails, kfunc desc is not added to tab->descs (previously it could be
added or not, depending on what failed).
Signed-off-by: Mykyta Yatsenko <yatsenko@meta.com>
Acked-by: Eduard Zingerman <eddyz87@gmail.com>
Link: https://lore.kernel.org/r/20251026203853.135105-9-mykyta.yatsenko5@gmail.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Add support for file dynptr.
Introduce struct bpf_dynptr_file_impl to hold internal state for file
dynptrs, with 64-bit size and offset support.
Introduce lifecycle management kfuncs:
- bpf_dynptr_from_file() for initialization
- bpf_dynptr_file_discard() for destruction
Extend existing helpers to support file dynptrs in:
- bpf_dynptr_read()
- bpf_dynptr_slice()
Write helpers (bpf_dynptr_write() and bpf_dynptr_data()) are not
modified, as file dynptr is read-only.
Signed-off-by: Mykyta Yatsenko <yatsenko@meta.com>
Acked-by: Eduard Zingerman <eddyz87@gmail.com>
Link: https://lore.kernel.org/r/20251026203853.135105-8-mykyta.yatsenko5@gmail.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Add the necessary verifier plumbing for the new file-backed dynptr type.
Introduce two kfuncs for its lifecycle management:
* bpf_dynptr_from_file() for initialization
* bpf_dynptr_file_discard() for destruction
Currently there is no mechanism for kfunc to release dynptr, this patch
add one:
* Dynptr release function sets meta->release_regno
* Call unmark_stack_slots_dynptr() if meta->release_regno is set and
dynptr ref_obj_id is set as well.
Signed-off-by: Mykyta Yatsenko <yatsenko@meta.com>
Acked-by: Eduard Zingerman <eddyz87@gmail.com>
Link: https://lore.kernel.org/r/20251026203853.135105-7-mykyta.yatsenko5@gmail.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
