The next patch would require doing postorder traversal of individual
subprograms. Facilitate this by moving env->cfg.insn_postorder
computation from check_cfg() to a separate pass, as check_cfg()
descends into called subprograms (and it needs to, because of
merge_callee_effects() logic).
env->cfg.insn_postorder is used only by compute_live_registers(),
this function does not track cross subprogram dependencies,
thus the change does not affect it's operation.
Signed-off-by: Eduard Zingerman <eddyz87@gmail.com>
Link: https://lore.kernel.org/r/20250918-callchain-sensitive-liveness-v3-5-c3cd27bacc60@gmail.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
stacksafe() is called in exact == NOT_EXACT mode only for states that
had been porcessed by clean_verifier_states(). The latter replaces
dead stack spills with a series of STACK_INVALID masks. Such masks are
already handled by stacksafe().
Signed-off-by: Eduard Zingerman <eddyz87@gmail.com>
Link: https://lore.kernel.org/r/20250918-callchain-sensitive-liveness-v3-3-c3cd27bacc60@gmail.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Prepare for bpf_reg_state->live field removal by leveraging
insn_aux_data->live_regs_before instead of bpf_reg_state->live in
compute_live_registers(). This is similar to logic in
func_states_equal(). No changes in verification performance for
selftests or sched_ext.
Signed-off-by: Eduard Zingerman <eddyz87@gmail.com>
Link: https://lore.kernel.org/r/20250918-callchain-sensitive-liveness-v3-2-c3cd27bacc60@gmail.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Prepare for bpf_reg_state->live field removal by introducing a
separate flag to track if clean_verifier_state() had been applied to
the state. No functional changes.
Signed-off-by: Eduard Zingerman <eddyz87@gmail.com>
Link: https://lore.kernel.org/r/20250918-callchain-sensitive-liveness-v3-1-c3cd27bacc60@gmail.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
No functional changes, except for the addition of the headers for the
kfuncs so that they can be used for signature verification.
Signed-off-by: KP Singh <kpsingh@kernel.org>
Link: https://lore.kernel.org/r/20250914215141.15144-8-kpsingh@kernel.org
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Currently only array maps are supported, but the implementation can be
extended for other maps and objects. The hash is memoized only for
exclusive and frozen maps as their content is stable until the exclusive
program modifies the map.
This is required for BPF signing, enabling a trusted loader program to
verify a map's integrity. The loader retrieves
the map's runtime hash from the kernel and compares it against an
expected hash computed at build time.
Signed-off-by: KP Singh <kpsingh@kernel.org>
Link: https://lore.kernel.org/r/20250914215141.15144-7-kpsingh@kernel.org
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Implement setters and getters that allow map to be registered as
exclusive to the specified program. The registration should be done
before the exclusive program is loaded.
Signed-off-by: KP Singh <kpsingh@kernel.org>
Acked-by: Andrii Nakryiko <andrii@kernel.org>
Link: https://lore.kernel.org/r/20250914215141.15144-5-kpsingh@kernel.org
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Use AF_ALG sockets to not have libbpf depend on OpenSSL. The helper is
used for the loader generation code to embed the metadata hash in the
loader program and also by the bpf_map__make_exclusive API to calculate
the hash of the program the map is exclusive to.
Acked-by: Andrii Nakryiko <andrii@kernel.org>
Signed-off-by: KP Singh <kpsingh@kernel.org>
Link: https://lore.kernel.org/r/20250914215141.15144-4-kpsingh@kernel.org
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Exclusive maps allow maps to only be accessed by program with a
program with a matching hash which is specified in the excl_prog_hash
attr.
For the signing use-case, this allows the trusted loader program
to load the map and verify the integrity
Signed-off-by: KP Singh <kpsingh@kernel.org>
Link: https://lore.kernel.org/r/20250914215141.15144-3-kpsingh@kernel.org
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Exclusive maps restrict map access to specific programs using a hash.
The current hash used for this is SHA1, which is prone to collisions.
This patch uses SHA256, which is more resilient against
collisions. This new hash is stored in bpf_prog and used by the verifier
to determine if a program can access a given exclusive map.
The original 64-bit tags are kept, as they are used by users as a short,
possibly colliding program identifier for non-security purposes.
Signed-off-by: KP Singh <kpsingh@kernel.org>
Link: https://lore.kernel.org/r/20250914215141.15144-2-kpsingh@kernel.org
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Kumar Kartikeya Dwivedi says:
====================
Update KF_RCU_PROTECTED
Currently, KF_RCU_PROTECTED only applies to iterator APIs and that too
in a convoluted fashion: the presence of this flag on the kfunc is used
to set MEM_RCU in iterator type, and the lack of RCU protection results
in an error only later, once next() or destroy() methods are invoked on
the iterator. While there is no bug, this is certainly a bit unintuitive,
and makes the enforcement of the flag iterator specific.
In the interest of making this flag useful for other upcoming kfuncs,
e.g. scx_bpf_cpu_curr() [0][1], add enforcement for invoking the kfunc
in an RCU critical section in general.
In addition to this, the aforementioned kfunc also needs to return an
RCU protected pointer, which currently has no generic kfunc flag or
annotation. Add such a flag as well while we are at it.
[0]: https://lore.kernel.org/all/20250903212311.369697-3-christian.loehle@arm.com
[1]: https://lore.kernel.org/all/20250909195709.92669-1-arighi@nvidia.com
Changelog:
----------
v2 -> v3
v2: https://lore.kernel.org/bpf/20250917032014.4060112-1-memxor@gmail.com
* Add back lost hunk reworking documentation for KF_RCU_PROTECTED.
v1 -> v2
v1: https://lore.kernel.org/bpf/20250915024731.1494251-1-memxor@gmail.com
* Drop KF_RET_RCU and fold change into KF_RCU_PROTECTED. (Andrea, Alexei)
* Update tests for non-struct pointer return values with KF_RCU_PROTECTED.
====================
Link: https://patch.msgid.link/20250917032755.4068726-1-memxor@gmail.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Add a couple of test cases to ensure RCU protection is kicked in
automatically, and the return type is as expected.
Signed-off-by: Kumar Kartikeya Dwivedi <memxor@gmail.com>
Acked-by: Eduard Zingerman <eddyz87@gmail.com>
Link: https://lore.kernel.org/r/20250917032755.4068726-3-memxor@gmail.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Currently, KF_RCU_PROTECTED only applies to iterator APIs and that too
in a convoluted fashion: the presence of this flag on the kfunc is used
to set MEM_RCU in iterator type, and the lack of RCU protection results
in an error only later, once next() or destroy() methods are invoked on
the iterator. While there is no bug, this is certainly a bit
unintuitive, and makes the enforcement of the flag iterator specific.
In the interest of making this flag useful for other upcoming kfuncs,
e.g. scx_bpf_cpu_curr() [0][1], add enforcement for invoking the kfunc
in an RCU critical section in general.
This would also mean that iterator APIs using KF_RCU_PROTECTED will
error out earlier, instead of throwing an error for lack of RCU CS
protection when next() or destroy() methods are invoked.
In addition to this, if the kfuncs tagged KF_RCU_PROTECTED return a
pointer value, ensure that this pointer value is only usable in an RCU
critical section. There might be edge cases where the return value is
special and doesn't need to imply MEM_RCU semantics, but in general, the
assumption should hold for the majority of kfuncs, and we can revisit
things if necessary later.
[0]: https://lore.kernel.org/all/20250903212311.369697-3-christian.loehle@arm.com
[1]: https://lore.kernel.org/all/20250909195709.92669-1-arighi@nvidia.com
Tested-by: Andrea Righi <arighi@nvidia.com>
Signed-off-by: Kumar Kartikeya Dwivedi <memxor@gmail.com>
Acked-by: Eduard Zingerman <eddyz87@gmail.com>
Link: https://lore.kernel.org/r/20250917032755.4068726-2-memxor@gmail.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
The current implementation seems incorrect and does NOT match the
comment above, use bpf_jit_binary_pack_finalize() instead.
Fixes: 1dad391dae ("bpf, arm64: use bpf_prog_pack for memory management")
Acked-by: Puranjay Mohan <puranjay@kernel.org>
Signed-off-by: Hengqi Chen <hengqi.chen@gmail.com>
Acked-by: Song Liu <song@kernel.org>
Acked-by: Puranjay Mohan <puranjay@kernel.org>
Link: https://lore.kernel.org/r/20250916232653.101004-1-hengqi.chen@gmail.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
This is a test case minimized from a syzbot reproducer from [1].
The test case triggers verifier.c:maybe_exit_scc() w/o
preceding call to verifier.c:maybe_enter_scc() on a speculative
symbolic execution path.
Here is verifier log for the test case:
Live regs before insn:
0: .......... (b7) r0 = 100
1 1: 0......... (7b) *(u64 *)(r10 -512) = r0
1 2: 0......... (b5) if r0 <= 0x0 goto pc-2
3: 0......... (95) exit
0: R1=ctx() R10=fp0
0: (b7) r0 = 100 ; R0_w=100
1: (7b) *(u64 *)(r10 -512) = r0 ; R0_w=100 R10=fp0 fp-512_w=100
2: (b5) if r0 <= 0x0 goto pc-2
mark_precise: ...
2: R0_w=100
3: (95) exit
from 2 to 1 (speculative execution): R0_w=scalar() R1=ctx() R10=fp0 fp-512_w=100
1: R0_w=scalar() R1=ctx() R10=fp0 fp-512_w=100
1: (7b) *(u64 *)(r10 -512) = r0
processed 5 insns (limit 1000000) max_states_per_insn 0 total_states 0 peak_states 0 mark_read 0
- Non-speculative execution path 0-3 does not allocate any checkpoints
(and hence does not call maybe_enter_scc()), and schedules a
speculative jump from 2 to 1.
- Speculative execution path stops immediately because of an infinite
loop detection and triggers verifier.c:update_branch_counts() ->
maybe_exit_scc() calls.
[1] https://lore.kernel.org/bpf/68c85acd.050a0220.2ff435.03a4.GAE@google.com/
Signed-off-by: Eduard Zingerman <eddyz87@gmail.com>
Link: https://lore.kernel.org/r/20250916212251.3490455-2-eddyz87@gmail.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Syzbot generated a program that triggers a verifier_bug() call in
maybe_exit_scc(). maybe_exit_scc() assumes that, when called for a
state with insn_idx in some SCC, there should be an instance of struct
bpf_scc_visit allocated for that SCC. Turns out the assumption does
not hold for speculative execution paths. See example in the next
patch.
maybe_scc_exit() is called from update_branch_counts() for states that
reach branch count of zero, meaning that path exploration for a
particular path is finished. Path exploration can finish in one of
three ways:
a. Verification error is found. In this case, update_branch_counts()
is called only for non-speculative paths.
b. Top level BPF_EXIT is reached. Such instructions are never a part of
an SCC, so compute_scc_callchain() in maybe_scc_exit() will return
false, and maybe_scc_exit() will return early.
c. A checkpoint is reached and matched. Checkpoints are created by
is_state_visited(), which calls maybe_enter_scc(), which allocates
bpf_scc_visit instances for checkpoints within SCCs.
Hence, for non-speculative symbolic execution paths, the assumption
still holds: if maybe_scc_exit() is called for a state within an SCC,
bpf_scc_visit instance must exist.
This patch removes the verifier_bug() call for speculative paths.
Fixes: c9e31900b5 ("bpf: propagate read/precision marks over state graph backedges")
Reported-by: syzbot+3afc814e8df1af64b653@syzkaller.appspotmail.com
Closes: https://lore.kernel.org/bpf/68c85acd.050a0220.2ff435.03a4.GAE@google.com/
Signed-off-by: Eduard Zingerman <eddyz87@gmail.com>
Link: https://lore.kernel.org/r/20250916212251.3490455-1-eddyz87@gmail.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
This patch adds tests covering the various paddings in ctx structures.
In case of sk_lookup BPF programs, the behavior is a bit different
because accesses to the padding are explicitly allowed. Other cases
result in a clear reject from the verifier.
Signed-off-by: Paul Chaignon <paul.chaignon@gmail.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Acked-by: Eduard Zingerman <eddyz87@gmail.com>
Acked-by: Daniel Borkmann <daniel@iogearbox.net>
Link: https://lore.kernel.org/bpf/3dc5f025e350aeb2bb1c257b87c577518e574aeb.1758094761.git.paul.chaignon@gmail.com
Move the sizeof_field and offsetofend macros from individual test files
to the common bpf_misc.h to avoid duplication.
Signed-off-by: Paul Chaignon <paul.chaignon@gmail.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Acked-by: Eduard Zingerman <eddyz87@gmail.com>
Acked-by: Daniel Borkmann <daniel@iogearbox.net>
Link: https://lore.kernel.org/bpf/97a3f3788bd3aec309100bc073a5c77130e371fd.1758094761.git.paul.chaignon@gmail.com
Syzkaller found a kernel warning on the following sock_addr program:
0: r0 = 0
1: r2 = *(u32 *)(r1 +60)
2: exit
which triggers:
verifier bug: error during ctx access conversion (0)
This is happening because offset 60 in bpf_sock_addr corresponds to an
implicit padding of 4 bytes, right after msg_src_ip4. Access to this
padding isn't rejected in sock_addr_is_valid_access and it thus later
fails to convert the access.
This patch fixes it by explicitly checking the various fields of
bpf_sock_addr in sock_addr_is_valid_access.
I checked the other ctx structures and is_valid_access functions and
didn't find any other similar cases. Other cases of (properly handled)
padding are covered in new tests in a subsequent patch.
Fixes: 1cedee13d2 ("bpf: Hooks for sys_sendmsg")
Reported-by: syzbot+136ca59d411f92e821b7@syzkaller.appspotmail.com
Signed-off-by: Paul Chaignon <paul.chaignon@gmail.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Acked-by: Eduard Zingerman <eddyz87@gmail.com>
Acked-by: Daniel Borkmann <daniel@iogearbox.net>
Closes: https://syzkaller.appspot.com/bug?extid=136ca59d411f92e821b7
Link: https://lore.kernel.org/bpf/b58609d9490649e76e584b0361da0abd3c2c1779.1758094761.git.paul.chaignon@gmail.com
Function bpf_patch_insn_data() has the following structure:
static struct bpf_prog *bpf_patch_insn_data(... env ...)
{
struct bpf_prog *new_prog;
struct bpf_insn_aux_data *new_data = NULL;
if (len > 1) {
new_data = vrealloc(...); // <--------- (1)
if (!new_data)
return NULL;
env->insn_aux_data = new_data; // <---- (2)
}
new_prog = bpf_patch_insn_single(env->prog, off, patch, len);
if (IS_ERR(new_prog)) {
...
vfree(new_data); // <----------------- (3)
return NULL;
}
... happy path ...
}
In case if bpf_patch_insn_single() returns an error the `new_data`
allocated at (1) will be freed at (3). However, at (2) this pointer
is stored in `env->insn_aux_data`. Which is freed unconditionally
by verifier.c:bpf_check() on both happy and error paths.
Thus, leading to double-free.
Fix this by removing vfree() call at (3), ownership over `new_data` is
already passed to `env->insn_aux_data` at this point.
Fixes: 77620d1267 ("bpf: use realloc in bpf_patch_insn_data")
Reported-by: Chris Mason <clm@meta.com>
Signed-off-by: Eduard Zingerman <eddyz87@gmail.com>
Link: https://lore.kernel.org/r/20250912-patch-insn-data-double-free-v1-1-af05bd85a21a@gmail.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Commit 0e2fb011a0 ("selftests/bpf: Clean up open-coded gettid syscall
invocations") addressed the issue that older libc may not have a gettid()
function call wrapper for the associated syscall.
A few more instances have crept into tests, use sys_gettid() instead, and
poison raw gettid() usage to avoid future issues.
Signed-off-by: Alan Maguire <alan.maguire@oracle.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Acked-by: Daniel Borkmann <daniel@iogearbox.net>
Link: https://lore.kernel.org/bpf/20250911163056.543071-1-alan.maguire@oracle.com
Kumar Kartikeya Dwivedi says:
====================
Remove use of current->cgns in bpf_cgroup_from_id
bpf_cgroup_from_id currently ends up doing a check on whether the cgroup
being looked up is a descendant of the root cgroup of the current task's
cgroup namespace. This leads to unreliable results since this kfunc can
be invoked from any arbitrary context, for any arbitrary value of
current. Fix this by removing namespace-awarness in the kfunc, and
include a test that detects such a case and fails without the fix.
Changelog:
----------
v2 -> v3
v2: https://lore.kernel.org/bpf/20250811195901.1651800-1-memxor@gmail.com
* Refactor cgroup_get_from_id into non-ns version. (Andrii)
* Address nits from Eduard.
v1 -> v2
v1: https://lore.kernel.org/bpf/20250811175045.1055202-1-memxor@gmail.com
* Add Ack from Tejun.
* Fix selftest to perform namespace migration and cgroup setup in a
child process to avoid changing test_progs namespace.
====================
Link: https://patch.msgid.link/20250915032618.1551762-1-memxor@gmail.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Make sure that we only switch the cgroup namespace and enter a new
cgroup in a child process separate from test_progs, to not mess up the
environment for subsequent tests.
To remove this cgroup, we need to wait for the child to exit, and then
rmdir its cgroup. If the read call fails, or waitpid succeeds, we know
the child exited (read call would fail when the last pipe end is closed,
otherwise waitpid waits until exit(2) is called). We then invoke a newly
introduced remove_cgroup_pid() helper, that identifies cgroup path using
the passed in pid of the now dead child, instead of using the current
process pid (getpid()).
Signed-off-by: Kumar Kartikeya Dwivedi <memxor@gmail.com>
Link: https://lore.kernel.org/r/20250915032618.1551762-3-memxor@gmail.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
The bpf_cgroup_from_id kfunc relies on cgroup_get_from_id to obtain the
cgroup corresponding to a given cgroup ID. This helper can be called in
a lot of contexts where the current thread can be random. A recent
example was its use in sched_ext's ops.tick(), to obtain the root cgroup
pointer. Since the current task can be whatever random user space task
preempted by the timer tick, this makes the behavior of the helper
unreliable.
Refactor out __cgroup_get_from_id as the non-namespace aware version of
cgroup_get_from_id, and change bpf_cgroup_from_id to make use of it.
There is no compatibility breakage here, since changing the namespace
against which the lookup is being done to the root cgroup namespace only
permits a wider set of lookups to succeed now. The cgroup IDs across
namespaces are globally unique, and thus don't need to be retranslated.
Reported-by: Dan Schatzberg <dschatzberg@meta.com>
Signed-off-by: Kumar Kartikeya Dwivedi <memxor@gmail.com>
Acked-by: Tejun Heo <tj@kernel.org>
Link: https://lore.kernel.org/r/20250915032618.1551762-2-memxor@gmail.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
For systems having CONFIG_NR_CPUS set to > 1024 in kernel config
the selftest fails as arena_spin_lock_irqsave() returns EOPNOTSUPP.
(eg - incase of powerpc default value for CONFIG_NR_CPUS is 8192)
The selftest is skipped incase bpf program returns EOPNOTSUPP,
with a descriptive message logged.
Tested-by: Venkat Rao Bagalkote <venkat88@linux.ibm.com>
Signed-off-by: Saket Kumar Bhaskar <skb99@linux.ibm.com>
Link: https://lore.kernel.org/r/20250913091337.1841916-1-skb99@linux.ibm.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Like commit fbdd61c94b ("selftests/bpf: Skip timer cases when bpf_timer is not supported"),
'timer_interrupt' test case should be skipped if verifier rejects
bpf_timer with returning -EOPNOTSUPP.
cd tools/testing/selftests/bpf
./test_progs -t timer
461 timer_interrupt:SKIP
Summary: 6/0 PASSED, 7 SKIPPED, 0 FAILED
Signed-off-by: Leon Hwang <leon.hwang@linux.dev>
Signed-off-by: Martin KaFai Lau <martin.lau@kernel.org>
Link: https://patch.msgid.link/20250915121657.28084-1-leon.hwang@linux.dev
With "bpftool prog tracelog", bpftool prints messages from the trace
pipe. To do so, it first needs to find the tracefs mount point to open
the pipe. Bpftool looks at a few "default" locations, including
/sys/kernel/debug/tracing and /sys/kernel/tracing.
Some of these locations, namely /tracing and /trace, are not standard.
They are in the list because some users used to hardcode the tracing
directory to short names; but we have no compelling reason to look at
these locations. If we fail to find the tracefs at the default
locations, we have an additional step to find it by parsing /proc/mounts
anyway, so it's safe to remove these entries from the list of default
locations to check.
Additionally, Alexei reports that looking for the tracefs at
/sys/kernel/debug/tracing may automatically mount the file system under
that location, and generate a kernel log message telling that
auto-mounting there is deprecated. To avoid this message, let's swap the
order for checking the potential mount points: try /sys/kernel/tracing
first, which should be the standard location nowadays. The kernel log
message may still appear if the tracefs is not mounted on
/sys/kernel/tracing when we run bpftool.
Reported-by: Alexei Starovoitov <ast@kernel.org>
Closes: https://lore.kernel.org/r/CAADnVQLcMi5YQhZKsU4z3S2uVUAGu_62C33G2Zx_ruG3uXa-Ug@mail.gmail.com/
Signed-off-by: Quentin Monnet <qmo@kernel.org>
Acked-by: Daniel Borkmann <daniel@iogearbox.net>
Link: https://lore.kernel.org/r/20250915134209.36568-1-qmo@kernel.org
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
The bpf_flush_icache() is done by bpf_arch_text_copy() already.
Remove the duplicated one in arch_prepare_bpf_trampoline().
Signed-off-by: Hengqi Chen <hengqi.chen@gmail.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Reviewed-by: Pu Lehui <pulehui@huawei.com>
Link: https://lore.kernel.org/bpf/20250904105119.21861-1-hengqi.chen@gmail.com
Puranjay Mohan says:
====================
bpf: report arena faults to BPF streams
Changes in v6->v7:
v6: https://lore.kernel.org/all/20250908163638.23150-1-puranjay@kernel.org/
- Added comments about the usage of arena_reg in x86 and arm64 jits. (Alexei)
- Used clear_lo32() for clearing the lower 32-bits of user_vm_start. (Alexei)
- Moved update of the old tests to use __stderr to a separate commit (Eduard)
- Used test__skip() in prog_tests/stream.c (Eduard)
- Start a sub-test for read / write
Changes in v5->v6:
v5: https://lore.kernel.org/all/20250901193730.43543-1-puranjay@kernel.org/
- Introduces __stderr and __stdout for easy testing of bpf streams
(Eduard)
- Add more test cases for arena fault reporting (subprog and callback)
- Fix main_prog_aux usage and return main_prog from find_from_stack_cb
(Kumar)
- Properly fix the build issue reported by kernel test robot
Changes in v4->v5:
v4: https://lore.kernel.org/all/20250827153728.28115-1-puranjay@kernel.org/
- Added patch 2 to introducing main_prog_aux for easier access to
streams.
- Fixed bug in fault handlers when arena_reg == dst_reg
- Updated selftest to check test above edge case.
- Added comments about the usage of barrier_var() in code and commit
message.
Changes in v3->v4:
v3: https://lore.kernel.org/all/20250827150113.15763-1-puranjay@kernel.org/
- Fixed a build issue when CONFIG_BPF_JIT=y and # CONFIG_BPF_SYSCALL is
not set
Changes in v2->v3:
v2: https://lore.kernel.org/all/20250811111828.13836-1-puranjay@kernel.org/
- Improved the selftest to check the exact fault address
- Dropped BPF_NO_KFUNC_PROTOTYPES and bpf_arena_alloc/free_pages() usage
- Rebased on bpf-next/master
Changes in v1->v2:
v1: https://lore.kernel.org/all/20250806085847.18633-1-puranjay@kernel.org/
- Changed variable and mask names for consistency (Yonghong)
- Added Acked-by: Yonghong Song <yonghong.song@linux.dev> on two patches
This set adds the support of reporting page faults inside arena to BPF
stderr stream. The reported address is the one that a user would expect
to see if they pass it to bpf_printk();
Here is an example output from the stderr stream and bpf_printk()
ERROR: Arena WRITE access at unmapped address 0xdeaddead0000
CPU: 9 UID: 0 PID: 502 Comm: test_progs
Call trace:
bpf_stream_stage_dump_stack+0xc0/0x150
bpf_prog_report_arena_violation+0x98/0xf0
ex_handler_bpf+0x5c/0x78
fixup_exception+0xf8/0x160
__do_kernel_fault+0x40/0x188
do_bad_area+0x70/0x88
do_translation_fault+0x54/0x98
do_mem_abort+0x4c/0xa8
el1_abort+0x44/0x70
el1h_64_sync_handler+0x50/0x108
el1h_64_sync+0x6c/0x70
bpf_prog_a64a9778d31b8e88_stream_arena_write_fault+0x84/0xc8
*(page) = 1; @ stream.c:100
bpf_prog_test_run_syscall+0x100/0x328
__sys_bpf+0x508/0xb98
__arm64_sys_bpf+0x2c/0x48
invoke_syscall+0x50/0x120
el0_svc_common.constprop.0+0x48/0xf8
do_el0_svc+0x28/0x40
el0_svc+0x48/0xf8
el0t_64_sync_handler+0xa0/0xe8
el0t_64_sync+0x198/0x1a0
Same address is printed by bpf_printk():
1389.078831: bpf_trace_printk: Read Address: 0xdeaddead0000
To make this possible, some extra metadata has to be passed to the bpf
exception handler, so the bpf exception handling mechanism for both
x86-64 and arm64 have been improved in this set.
The streams selftest has been updated to test this new feature.
====================
Link: https://patch.msgid.link/20250911145808.58042-1-puranjay@kernel.org
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Add selftests for testing the reporting of arena page faults through BPF
streams. Two new bpf programs are added that read and write to an
unmapped arena address and the fault reporting is verified in the
userspace through streams.
The added bpf programs need to access the user_vm_start in struct
bpf_arena, this is done by casting &arena to struct bpf_arena *, but
barrier_var() is used on this ptr before accessing ptr->user_vm_start;
to stop GCC from issuing an out-of-bound access due to the cast from
smaller map struct to larger "struct bpf_arena"
Signed-off-by: Puranjay Mohan <puranjay@kernel.org>
Acked-by: Eduard Zingerman <eddyz87@gmail.com>
Link: https://lore.kernel.org/r/20250911145808.58042-7-puranjay@kernel.org
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Start using __stderr directly in the bpf programs to test the reporting
of may_goto timeout detection and spin_lock dead lock detection.
Signed-off-by: Puranjay Mohan <puranjay@kernel.org>
Acked-by: Eduard Zingerman <eddyz87@gmail.com>
Link: https://lore.kernel.org/r/20250911145808.58042-6-puranjay@kernel.org
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Add __stderr and __stdout to validate the output of BPF streams for bpf
selftests. Similar to __xlated, __jited, etc., __stderr/out can be used
in the BPF progs to compare a string (regex supported) to the output in
the bpf streams.
Signed-off-by: Puranjay Mohan <puranjay@kernel.org>
Acked-by: Eduard Zingerman <eddyz87@gmail.com>
Link: https://lore.kernel.org/r/20250911145808.58042-5-puranjay@kernel.org
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Begin reporting arena page faults and the faulting address to BPF
program's stderr, this patch adds support in the arm64 and x86-64 JITs,
support for other archs can be added later.
The fault handlers receive the 32 bit address in the arena region so
the upper 32 bits of user_vm_start is added to it before printing the
address. This is what the user would expect to see as this is what is
printed by bpf_printk() is you pass it an address returned by
bpf_arena_alloc_pages();
Signed-off-by: Puranjay Mohan <puranjay@kernel.org>
Acked-by: Yonghong Song <yonghong.song@linux.dev>
Link: https://lore.kernel.org/r/20250911145808.58042-4-puranjay@kernel.org
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
BPF streams are only valid for the main programs, to make it easier to
access streams from subprogs, introduce main_prog_aux in struct
bpf_prog_aux.
prog->aux->main_prog_aux = prog->aux, for main programs and
prog->aux->main_prog_aux = main_prog->aux, for subprograms.
Make bpf_prog_find_from_stack() use the added main_prog_aux to return
the mainprog when a subprog is found on the stack.
Signed-off-by: Puranjay Mohan <puranjay@kernel.org>
Acked-by: Eduard Zingerman <eddyz87@gmail.com>
Link: https://lore.kernel.org/r/20250911145808.58042-3-puranjay@kernel.org
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
BPF loads with BPF_PROBE_MEM(SX) can load from unsafe pointers and the
JIT adds an exception table entry for the JITed instruction which allows
the exeption handler to set the destination register of the load to zero
and continue execution from the next instruction.
As all arm64 instructions are AARCH64_INSN_SIZE size, the exception
handler can just increment the pc by AARCH64_INSN_SIZE without needing
the exact address of the instruction following the the faulting
instruction.
Simplify the exception table usage in arm64 JIT by only saving the
destination register in ex->fixup and drop everything related to
the fixup_offset. The fault handler is modified to add AARCH64_INSN_SIZE
to the pc.
Signed-off-by: Puranjay Mohan <puranjay@kernel.org>
Acked-by: Yonghong Song <yonghong.song@linux.dev>
Acked-by: Kumar Kartikeya Dwivedi <memxor@gmail.com>
Acked-by: Xu Kuohai <xukuohai@huawei.com>
Link: https://lore.kernel.org/r/20250911145808.58042-2-puranjay@kernel.org
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
- ptep_modify_prot_start() may be called in a loop, which might lead
to the preempt_count overflow due to the unnecessary preemption
disabling. Do not disable preemption to prevent the overflow
- Events of type PERF_TYPE_HARDWARE are not tested for sampling and
return -EOPNOTSUPP eventually. Instead, deny all sampling events by
CPUMF counter facility and return -ENOENT to allow other PMUs to be
tried
- The PAI PMU driver returns -EINVAL if an event out of its range.
That aborts a search for an alternative PMU driver. Instead, return
-ENOENT to allow other PMUs to be tried
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Merge tag 's390-6.17-4' of git://git.kernel.org/pub/scm/linux/kernel/git/s390/linux
Pull s390 fixes from Alexander Gordeev:
- ptep_modify_prot_start() may be called in a loop, which might lead to
the preempt_count overflow due to the unnecessary preemption
disabling. Do not disable preemption to prevent the overflow
- Events of type PERF_TYPE_HARDWARE are not tested for sampling and
return -EOPNOTSUPP eventually.
Instead, deny all sampling events by CPUMF counter facility and
return -ENOENT to allow other PMUs to be tried
- The PAI PMU driver returns -EINVAL if an event out of its range. That
aborts a search for an alternative PMU driver.
Instead, return -ENOENT to allow other PMUs to be tried
* tag 's390-6.17-4' of git://git.kernel.org/pub/scm/linux/kernel/git/s390/linux:
s390/cpum_cf: Deny all sampling events by counter PMU
s390/pai: Deny all events not handled by this PMU
s390/mm: Prevent possible preempt_count overflow
- Restore a pm_restrict_gfp_mask() call in hibernation_snapshot() that
was removed incorrectly during the 6.16 development cycle (Rafael
Wysocki)
- Introduce a function for registering a perf domain without triggering
a system-wide CPU capacity update and make the intel_pstate driver
use it to avoid reocurring unsuccessful attempts to update capacities
of all CPUs in the system (Rafael Wysocki)
- Fix setting of CPPC.min_perf in the active mode with performance
governor in the amd-pstate driver to restore its expected behavior
changed recently (Gautham Shenoy)
- Avoid mistakenly setting EPP to 0 in the amd-pstate driver after
system resume as a result of recent code changes (Mario Limonciello)
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Merge tag 'pm-6.17-rc6' of git://git.kernel.org/pub/scm/linux/kernel/git/rafael/linux-pm
Pull power management fixes from Rafael Wysocki:
"These fix a nasty hibernation regression introduced during the 6.16
cycle, an issue related to energy model management occurring on Intel
hybrid systems where some CPUs are offline to start with, and two
regressions in the amd-pstate driver:
- Restore a pm_restrict_gfp_mask() call in hibernation_snapshot()
that was removed incorrectly during the 6.16 development cycle
(Rafael Wysocki)
- Introduce a function for registering a perf domain without
triggering a system-wide CPU capacity update and make the
intel_pstate driver use it to avoid reocurring unsuccessful
attempts to update capacities of all CPUs in the system (Rafael
Wysocki)
- Fix setting of CPPC.min_perf in the active mode with performance
governor in the amd-pstate driver to restore its expected behavior
changed recently (Gautham Shenoy)
- Avoid mistakenly setting EPP to 0 in the amd-pstate driver after
system resume as a result of recent code changes (Mario
Limonciello)"
* tag 'pm-6.17-rc6' of git://git.kernel.org/pub/scm/linux/kernel/git/rafael/linux-pm:
PM: hibernate: Restrict GFP mask in hibernation_snapshot()
PM: EM: Add function for registering a PD without capacity update
cpufreq/amd-pstate: Fix a regression leading to EPP 0 after resume
cpufreq/amd-pstate: Fix setting of CPPC.min_perf in active mode for performance governor
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Merge tag 'for-6.17-rc5-tag' of git://git.kernel.org/pub/scm/linux/kernel/git/kdave/linux
Pull btrfs fixes from David Sterba:
- fix delayed inode tracking in xarray, eviction can race with
insertion and leave behind a disconnected inode
- on systems with large page (64K) and small block size (4K) fix
compression read that can return partially filled folio
- slightly relax compression option format for backward compatibility,
allow to specify level for LZO although there's only one
- fix simple quota accounting of compressed extents
- validate minimum device size in 'device add'
- update maintainers' entry
* tag 'for-6.17-rc5-tag' of git://git.kernel.org/pub/scm/linux/kernel/git/kdave/linux:
btrfs: don't allow adding block device of less than 1 MB
MAINTAINERS: update btrfs entry
btrfs: fix subvolume deletion lockup caused by inodes xarray race
btrfs: fix corruption reading compressed range when block size is smaller than page size
btrfs: accept and ignore compression level for lzo
btrfs: fix squota compressed stats leak
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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:
"A number of fixes accumulated due to summer vacations
- Fix out-of-bounds dynptr write in bpf_crypto_crypt() kfunc which
was misidentified as a security issue (Daniel Borkmann)
- Update the list of BPF selftests maintainers (Eduard Zingerman)
- Fix selftests warnings with icecc compiler (Ilya Leoshkevich)
- Disable XDP/cpumap direct return optimization (Jesper Dangaard
Brouer)
- Fix unexpected get_helper_proto() result in unusual configuration
BPF_SYSCALL=y and BPF_EVENTS=n (Jiri Olsa)
- Allow fallback to interpreter when JIT support is limited (KaFai
Wan)
- Fix rqspinlock and choose trylock fallback for NMI waiters. Pick
the simplest fix. More involved fix is targeted bpf-next (Kumar
Kartikeya Dwivedi)
- Fix cleanup when tcp_bpf_send_verdict() fails to allocate
psock->cork (Kuniyuki Iwashima)
- Disallow bpf_timer in PREEMPT_RT for now. Proper solution is being
discussed for bpf-next. (Leon Hwang)
- Fix XSK cq descriptor production (Maciej Fijalkowski)
- Tell memcg to use allow_spinning=false path in bpf_timer_init() to
avoid lockup in cgroup_file_notify() (Peilin Ye)
- Fix bpf_strnstr() to handle suffix match cases (Rong Tao)"
* tag 'bpf-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/bpf/bpf:
selftests/bpf: Skip timer cases when bpf_timer is not supported
bpf: Reject bpf_timer for PREEMPT_RT
tcp_bpf: Call sk_msg_free() when tcp_bpf_send_verdict() fails to allocate psock->cork.
bpf: Tell memcg to use allow_spinning=false path in bpf_timer_init()
bpf: Allow fall back to interpreter for programs with stack size <= 512
rqspinlock: Choose trylock fallback for NMI waiters
xsk: Fix immature cq descriptor production
bpf: Update the list of BPF selftests maintainers
selftests/bpf: Add tests for bpf_strnstr
selftests/bpf: Fix "expression result unused" warnings with icecc
bpf: Fix bpf_strnstr() to handle suffix match cases better
selftests/bpf: Extend crypto_sanity selftest with invalid dst buffer
bpf: Fix out-of-bounds dynptr write in bpf_crypto_crypt
bpf: Check the helper function is valid in get_helper_proto
bpf, cpumap: Disable page_pool direct xdp_return need larger scope
Merge a hibernation regression fix and an fix related to energy model
management for 6.17-rc6
* pm-sleep:
PM: hibernate: Restrict GFP mask in hibernation_snapshot()
* pm-em:
PM: EM: Add function for registering a PD without capacity update
or aren't considered necessary for -stable kernels. 14 of these fixes are
for MM.
This includes
- a 3-patch kexec series from Breno that fixes a recently introduced
use-uninitialized bug,
- e 2-patch DAMON series from Quanmin Yan that avoids div-by-zero
crashes which can occur if the operator uses poorly-chosen insmod
parameters.
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Merge tag 'mm-hotfixes-stable-2025-09-10-20-00' of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm
Pull misc fixes from Andrew Morton:
"20 hotfixes. 15 are cc:stable and the remainder address post-6.16
issues or aren't considered necessary for -stable kernels. 14 of these
fixes are for MM.
This includes
- kexec fixes from Breno for a recently introduced
use-uninitialized bug
- DAMON fixes from Quanmin Yan to avoid div-by-zero crashes
which can occur if the operator uses poorly-chosen insmod
parameters
and misc singleton fixes"
* tag 'mm-hotfixes-stable-2025-09-10-20-00' of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm:
MAINTAINERS: add tree entry to numa memblocks and emulation block
mm/damon/sysfs: fix use-after-free in state_show()
proc: fix type confusion in pde_set_flags()
compiler-clang.h: define __SANITIZE_*__ macros only when undefined
mm/vmalloc, mm/kasan: respect gfp mask in kasan_populate_vmalloc()
ocfs2: fix recursive semaphore deadlock in fiemap call
mm/memory-failure: fix VM_BUG_ON_PAGE(PagePoisoned(page)) when unpoison memory
mm/mremap: fix regression in vrm->new_addr check
percpu: fix race on alloc failed warning limit
mm/memory-failure: fix redundant updates for already poisoned pages
s390: kexec: initialize kexec_buf struct
riscv: kexec: initialize kexec_buf struct
arm64: kexec: initialize kexec_buf struct in load_other_segments()
mm/damon/reclaim: avoid divide-by-zero in damon_reclaim_apply_parameters()
mm/damon/lru_sort: avoid divide-by-zero in damon_lru_sort_apply_parameters()
mm/damon/core: set quota->charged_from to jiffies at first charge window
mm/hugetlb: add missing hugetlb_lock in __unmap_hugepage_range()
init/main.c: fix boot time tracing crash
mm/memory_hotplug: fix hwpoisoned large folio handling in do_migrate_range()
mm/khugepaged: fix the address passed to notifier on testing young
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Merge tag 'vmscape-for-linus-20250904' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip
Pull vmescape mitigation fixes from Dave Hansen:
"Mitigate vmscape issue with indirect branch predictor flushes.
vmscape is a vulnerability that essentially takes Spectre-v2 and
attacks host userspace from a guest. It particularly affects
hypervisors like QEMU.
Even if a hypervisor may not have any sensitive data like disk
encryption keys, guest-userspace may be able to attack the
guest-kernel using the hypervisor as a confused deputy.
There are many ways to mitigate vmscape using the existing Spectre-v2
defenses like IBRS variants or the IBPB flushes. This series focuses
solely on IBPB because it works universally across vendors and all
vulnerable processors. Further work doing vendor and model-specific
optimizations can build on top of this if needed / wanted.
Do the normal issue mitigation dance:
- Add the CPU bug boilerplate
- Add a list of vulnerable CPUs
- Use IBPB to flush the branch predictors after running guests"
* tag 'vmscape-for-linus-20250904' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
x86/vmscape: Add old Intel CPUs to affected list
x86/vmscape: Warn when STIBP is disabled with SMT
x86/bugs: Move cpu_bugs_smt_update() down
x86/vmscape: Enable the mitigation
x86/vmscape: Add conditional IBPB mitigation
x86/vmscape: Enumerate VMSCAPE bug
Documentation/hw-vuln: Add VMSCAPE documentation
Stable patches:
- Revert "SUNRPC: Don't allow waiting for exiting tasks" as it is
breaking ltp tests.
Bugfixes:
- Another set of fixes to the tracking of NFSv4 server capabilities
when crossing filesystem boundaries.
- Localio fix to restore credentials and prevent triggering a BUG_ON().
- Fix to prevent flapping of the localio on/off trigger.
- Protections against 'eof page pollution' as demonstrated in xfstests
generic/363.
- Series of patches to ensure correct ordering of O_DIRECT i/o and
truncate, fallocate and copy functions.
- Fix a NULL pointer check in flexfiles reads that regresses 6.17.
- Correct a typo that breaks flexfiles layout segment processing.
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Merge tag 'nfs-for-6.17-3' of git://git.linux-nfs.org/projects/trondmy/linux-nfs
Pull NFS client fixes from Trond Myklebust:
"Stable patches:
- Revert "SUNRPC: Don't allow waiting for exiting tasks" as it is
breaking ltp tests
Bugfixes:
- Another set of fixes to the tracking of NFSv4 server capabilities
when crossing filesystem boundaries
- Localio fix to restore credentials and prevent triggering a
BUG_ON()
- Fix to prevent flapping of the localio on/off trigger
- Protections against 'eof page pollution' as demonstrated in
xfstests generic/363
- Series of patches to ensure correct ordering of O_DIRECT i/o and
truncate, fallocate and copy functions
- Fix a NULL pointer check in flexfiles reads that regresses 6.17
- Correct a typo that breaks flexfiles layout segment processing"
* tag 'nfs-for-6.17-3' of git://git.linux-nfs.org/projects/trondmy/linux-nfs:
NFSv4/flexfiles: Fix layout merge mirror check.
SUNRPC: call xs_sock_process_cmsg for all cmsg
Revert "SUNRPC: Don't allow waiting for exiting tasks"
NFS: Fix the marking of the folio as up to date
NFS: nfs_invalidate_folio() must observe the offset and size arguments
NFSv4.2: Serialise O_DIRECT i/o and copy range
NFSv4.2: Serialise O_DIRECT i/o and clone range
NFSv4.2: Serialise O_DIRECT i/o and fallocate()
NFS: Serialise O_DIRECT i/o and truncate()
NFSv4.2: Protect copy offload and clone against 'eof page pollution'
NFS: Protect against 'eof page pollution'
flexfiles/pNFS: fix NULL checks on result of ff_layout_choose_ds_for_read
nfs/localio: avoid bouncing LOCALIO if nfs_client_is_local()
nfs/localio: restore creds before releasing pageio data
NFSv4: Clear the NFS_CAP_XATTR flag if not supported by the server
NFSv4: Clear NFS_CAP_OPEN_XOR and NFS_CAP_DELEGTIME if not supported
NFSv4: Clear the NFS_CAP_FS_LOCATIONS flag if it is not set
NFSv4: Don't clear capabilities that won't be reset
Leon Hwang says:
====================
bpf: Reject bpf_timer for PREEMPT_RT
While running './test_progs -t timer' to validate the test case from
"selftests/bpf: Introduce experimental bpf_in_interrupt()"[0] for
PREEMPT_RT, I encountered a kernel warning:
BUG: sleeping function called from invalid context at kernel/locking/spinlock_rt.c:48
To address this, reject bpf_timer usage in the verifier when
PREEMPT_RT is enabled, and skip the corresponding timer selftests.
Changes:
v2 -> v3:
* Drop skipping test case 'timer_interrupt'.
* Address comments from Alexei:
* Respin targeting bpf tree.
* Trim commit log.
v1 -> v2:
* Skip test case 'timer_interrupt'.
Links:
[0] https://lore.kernel.org/bpf/20250903140438.59517-1-leon.hwang@linux.dev/
====================
Link: https://patch.msgid.link/20250910125740.52172-1-leon.hwang@linux.dev
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
When enable CONFIG_PREEMPT_RT, the kernel will warn when run timer
selftests by './test_progs -t timer':
BUG: sleeping function called from invalid context at kernel/locking/spinlock_rt.c:48
In order to avoid such warning, reject bpf_timer in verifier when
PREEMPT_RT is enabled.
Signed-off-by: Leon Hwang <leon.hwang@linux.dev>
Link: https://lore.kernel.org/r/20250910125740.52172-2-leon.hwang@linux.dev
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
