Commit Graph

1412100 Commits

Author SHA1 Message Date
Puranjay Mohan
c336b0b327 bpf: arena: populate vm_area without allocating memory
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>
2025-12-23 11:29:59 -08:00
Daniel Gomez
ac1c5bc7c4 bpf: crypto: replace -EEXIST with -EBUSY
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>
2025-12-22 22:25:09 -08:00
Alexei Starovoitov
b0004a8223 Merge branch 'allow-calling-kfuncs-from-raw_tp-programs'
Puranjay Mohan says:

====================
Allow calling kfuncs from raw_tp programs

V1: https://lore.kernel.org/all/20251218145514.339819-1-puranjay@kernel.org/
Changes in V1->V2:
- Update selftests to allow success for raw_tp programs calling kfuncs.

This set enables calling kfuncs from raw_tp programs.
====================

Link: https://patch.msgid.link/20251222133250.1890587-1-puranjay@kernel.org
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
2025-12-22 22:23:39 -08:00
Puranjay Mohan
83dd46ecb6 selftests: bpf: fix tests with raw_tp calling kfuncs
As the previous commit allowed raw_tp programs to call kfuncs, so of the
selftests that were expected to fail will now succeed.

Signed-off-by: Puranjay Mohan <puranjay@kernel.org>
Acked-by: Yonghong Song <yonghong.song@linux.dev>
Link: https://lore.kernel.org/r/20251222133250.1890587-3-puranjay@kernel.org
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
2025-12-22 22:23:38 -08:00
Puranjay Mohan
342297d511 bpf: allow calling kfuncs from raw_tp programs
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>
2025-12-22 22:23:38 -08:00
Alexei Starovoitov
042d4c0642 Merge branch 'mm-bpf-kfuncs-to-access-memcg-data'
Roman Gushchin says:

====================
mm: bpf kfuncs to access memcg data

Introduce kfuncs to simplify the access to the memcg data.
These kfuncs can be used to accelerate monitoring use cases and
for implementing custom OOM policies once BPF OOM is landed.

This patchset was separated out from the BPF OOM patchset to simplify
the logistics and accelerate the landing of the part which is useful
by itself. No functional changes since BPF OOM v2.

v4:
  - refactored memcg vm event and stat item idx checks (by Alexei)

v3:
  - dropped redundant kfuncs flags (by Alexei)
  - fixed kdocs warnings (by Alexei)
  - merged memcg stats access patches into one (by Alexei)
  - restored root memcg usage reporting, added a comment
  - added checks for enum boundaries
  - added Shakeel and JP as co-maintainers (by Shakeel)

v2:
  - added mem_cgroup_disabled() checks (by Shakeel B.)
  - added special handling of the root memcg in bpf_mem_cgroup_usage()
  (by Shakeel B.)
  - minor fixes in the kselftest (by Shakeel B.)
  - added a MAINTAINERS entry (by Shakeel B.)

v1:
  https://lore.kernel.org/bpf/87ike29s5r.fsf@linux.dev/T/#t
====================

Link: https://patch.msgid.link/20251223044156.208250-1-roman.gushchin@linux.dev
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
2025-12-22 22:20:22 -08:00
Roman Gushchin
6e57cdde70 MAINTAINERS: add an entry for MM BPF extensions
Let's create a separate entry for MM BPF extensions: these patches
often require an attention from both bpf and mm communities.

Signed-off-by: Roman Gushchin <roman.gushchin@linux.dev>
Link: https://lore.kernel.org/r/20251223044156.208250-7-roman.gushchin@linux.dev
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
2025-12-22 22:20:22 -08:00
JP Kobryn
6bce6ddbe6 bpf: selftests: selftests for memcg stat kfuncs
Add test coverage for the kfuncs that fetch memcg stats. Using some common
stats, test scenarios ensuring that the given stat increases by some
arbitrary amount. The stats selected cover the three categories represented
by the enums: node_stat_item, memcg_stat_item, vm_event_item.

Since only a subset of all stats are queried, use a static struct made up
of fields for each stat. Write to the struct with the fetched values when
the bpf program is invoked and read the fields in the user mode program for
verification.

Signed-off-by: JP Kobryn <inwardvessel@gmail.com>
Signed-off-by: Roman Gushchin <roman.gushchin@linux.dev>
Link: https://lore.kernel.org/r/20251223044156.208250-6-roman.gushchin@linux.dev
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
2025-12-22 22:20:22 -08:00
Roman Gushchin
99430ab8b8 mm: introduce BPF kfuncs to access memcg statistics and events
Introduce BPF kfuncs to conveniently access memcg data:
  - bpf_mem_cgroup_vm_events(),
  - bpf_mem_cgroup_memory_events(),
  - bpf_mem_cgroup_usage(),
  - bpf_mem_cgroup_page_state(),
  - bpf_mem_cgroup_flush_stats().

These functions are useful for implementing BPF OOM policies, but
also can be used to accelerate access to the memcg data. Reading
it through cgroupfs is much more expensive, roughly 5x, mostly
because of the need to convert the data into the text and back.

JP Kobryn:
An experiment was setup to compare the performance of a program that
uses the traditional method of reading memory.stat vs a program using
the new kfuncs. The control program opens up the root memory.stat file
and for 1M iterations reads, converts the string values to numeric data,
then seeks back to the beginning. The experimental program sets up the
requisite libbpf objects and for 1M iterations invokes a bpf program
which uses the kfuncs to fetch all available stats for node_stat_item,
memcg_stat_item, and vm_event_item types.

The results showed a significant perf benefit on the experimental side,
outperforming the control side by a margin of 93%. In kernel mode,
elapsed time was reduced by 80%, while in user mode, over 99% of time
was saved.

control: elapsed time
real    0m38.318s
user    0m25.131s
sys     0m13.070s

experiment: elapsed time
real    0m2.789s
user    0m0.187s
sys     0m2.512s

control: perf data
33.43% a.out libc.so.6         [.] __vfscanf_internal
 6.88% a.out [kernel.kallsyms] [k] vsnprintf
 6.33% a.out libc.so.6         [.] _IO_fgets
 5.51% a.out [kernel.kallsyms] [k] format_decode
 4.31% a.out libc.so.6         [.] __GI_____strtoull_l_internal
 3.78% a.out [kernel.kallsyms] [k] string
 3.53% a.out [kernel.kallsyms] [k] number
 2.71% a.out libc.so.6         [.] _IO_sputbackc
 2.41% a.out [kernel.kallsyms] [k] strlen
 1.98% a.out a.out             [.] main
 1.70% a.out libc.so.6         [.] _IO_getline_info
 1.51% a.out libc.so.6         [.] __isoc99_sscanf
 1.47% a.out [kernel.kallsyms] [k] memory_stat_format
 1.47% a.out [kernel.kallsyms] [k] memcpy_orig
 1.41% a.out [kernel.kallsyms] [k] seq_buf_printf

experiment: perf data
10.55% memcgstat bpf_prog_..._query [k] bpf_prog_16aab2f19fa982a7_query
 6.90% memcgstat [kernel.kallsyms]  [k] memcg_page_state_output
 3.55% memcgstat [kernel.kallsyms]  [k] _raw_spin_lock
 3.12% memcgstat [kernel.kallsyms]  [k] memcg_events
 2.87% memcgstat [kernel.kallsyms]  [k] __memcg_slab_post_alloc_hook
 2.73% memcgstat [kernel.kallsyms]  [k] kmem_cache_free
 2.70% memcgstat [kernel.kallsyms]  [k] entry_SYSRETQ_unsafe_stack
 2.25% memcgstat [kernel.kallsyms]  [k] __memcg_slab_free_hook
 2.06% memcgstat [kernel.kallsyms]  [k] get_page_from_freelist

Signed-off-by: Roman Gushchin <roman.gushchin@linux.dev>
Co-developed-by: JP Kobryn <inwardvessel@gmail.com>
Signed-off-by: JP Kobryn <inwardvessel@gmail.com>
Link: https://lore.kernel.org/r/20251223044156.208250-5-roman.gushchin@linux.dev
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
2025-12-22 22:20:22 -08:00
Roman Gushchin
5c7db3239c mm: introduce bpf_get_root_mem_cgroup() BPF kfunc
Introduce a BPF kfunc to get a trusted pointer to the root memory
cgroup. It's very handy to traverse the full memcg tree, e.g.
for handling a system-wide OOM.

It's possible to obtain this pointer by traversing the memcg tree
up from any known memcg, but it's sub-optimal and makes BPF programs
more complex and less efficient.

bpf_get_root_mem_cgroup() has a KF_ACQUIRE | KF_RET_NULL semantics,
however in reality it's not necessary to bump the corresponding
reference counter - root memory cgroup is immortal, reference counting
is skipped, see css_get(). Once set, root_mem_cgroup is always a valid
memcg pointer. It's safe to call bpf_put_mem_cgroup() for the pointer
obtained with bpf_get_root_mem_cgroup(), it's effectively a no-op.

Signed-off-by: Roman Gushchin <roman.gushchin@linux.dev>
Link: https://lore.kernel.org/r/20251223044156.208250-4-roman.gushchin@linux.dev
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
2025-12-22 22:20:21 -08:00
Roman Gushchin
5904db9891 mm: introduce BPF kfuncs to deal with memcg pointers
To effectively operate with memory cgroups in BPF there is a need
to convert css pointers to memcg pointers. A simple container_of
cast which is used in the kernel code can't be used in BPF because
from the verifier's point of view that's a out-of-bounds memory access.

Introduce helper get/put kfuncs which can be used to get
a refcounted memcg pointer from the css pointer:
  - bpf_get_mem_cgroup,
  - bpf_put_mem_cgroup.

bpf_get_mem_cgroup() can take both memcg's css and the corresponding
cgroup's "self" css. It allows it to be used with the existing cgroup
iterator which iterates over cgroup tree, not memcg tree.

Signed-off-by: Roman Gushchin <roman.gushchin@linux.dev>
Link: https://lore.kernel.org/r/20251223044156.208250-3-roman.gushchin@linux.dev
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
2025-12-22 22:20:21 -08:00
Roman Gushchin
4221de8c41 mm: declare memcg_page_state_output() in memcontrol.h
To use memcg_page_state_output() in bpf_memcontrol.c move the
declaration from v1-specific memcontrol-v1.h to memcontrol.h.

Signed-off-by: Roman Gushchin <roman.gushchin@linux.dev>
Acked-by: Michal Hocko <mhocko@suse.com>
Acked-by: Shakeel Butt <shakeel.butt@linux.dev>
Link: https://lore.kernel.org/r/20251223044156.208250-2-roman.gushchin@linux.dev
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
2025-12-22 22:20:21 -08:00
Puranjay Mohan
f785a31395 bpf: arm64: Fix sparse warnings
ctx->image is declared as __le32 because arm64 instructions are LE
regardless of CPU's runtime endianness. emit_u32_data() emits raw data
and not instructions so cast the value to __le32 to fix the sparse
warning.

Cast function pointer to void * before doing arithmetic.

Signed-off-by: Puranjay Mohan <puranjay@kernel.org>
Link: https://lore.kernel.org/r/20251219191310.3204425-1-puranjay@kernel.org
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
2025-12-21 16:57:23 -08:00
Matt Bobrowski
d2749ae85a selftests/bpf: add test case for BPF LSM hook bpf_lsm_mmap_file
Add a trivial test case asserting that the BPF verifier enforces
PTR_MAYBE_NULL semantics on the struct file pointer argument of BPF
LSM hook bpf_lsm_mmap_file().

Dereferencing the struct file pointer passed into bpf_lsm_mmap_file()
without explicitly performing a NULL check first should not be
permitted by the BPF verifier as it can lead to NULL pointer
dereferences and a kernel crash.

Signed-off-by: Matt Bobrowski <mattbobrowski@google.com>
Acked-by: Song Liu <song@kernel.org>
Link: https://lore.kernel.org/r/20251216133000.3690723-2-mattbobrowski@google.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
2025-12-21 10:56:33 -08:00
Matt Bobrowski
94e948b7e6 bpf: annotate file argument as __nullable in bpf_lsm_mmap_file
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>
2025-12-21 10:56:33 -08:00
Uros Bizjak
e09f6be4a3 x86/bpf: Avoid emitting LOCK prefix for XCHG atomic ops
The x86 XCHG instruction is implicitly locked when one of the
operands is a memory location, making an explicit LOCK prefix
unnecessary.

Stop emitting the LOCK prefix for BPF_XCHG in the JIT atomic
read-modify-write helpers. This avoids redundant instruction
prefixes while preserving correct atomic semantics.

No functional change for other atomic operations.

Signed-off-by: Uros Bizjak <ubizjak@gmail.com>
Cc: Alexei Starovoitov <ast@kernel.org>
Cc: Daniel Borkmann <daniel@iogearbox.net>
Cc: Andrii Nakryiko <andrii@kernel.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Dave Hansen <dave.hansen@linux.intel.com>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Link: https://lore.kernel.org/r/20251208163420.7643-1-ubizjak@gmail.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
2025-12-21 10:55:55 -08:00
Alexei Starovoitov
c2f2f005a1 Merge branch 'bpf-optimize-recursion-detection-on-arm64'
Puranjay Mohan says:

====================
bpf: Optimize recursion detection on arm64

V2: https://lore.kernel.org/all/20251217233608.2374187-1-puranjay@kernel.org/
Changes in v2->v3:
- Added acked by Yonghong
- Patch 2:
        - Change alignment of active from 8 to 4
        - Use le32_to_cpu in place of get_unaligned_le32()

V1: https://lore.kernel.org/all/20251217162830.2597286-1-puranjay@kernel.org/
Changes in V1->V2:
- Patch 2:
        - Put preempt_enable()/disable() around RMW accesses to mitigate
          race conditions. Because on CONFIG_PREEMPT_RCU and sleepable
	  bpf programs, preemption can cause no bpf prog to execute in
	  case of recursion.

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.

It was discovered in [1] that per-CPU atomics that don't return a value
were extremely slow on some arm64 platforms, Catalin added a fix in
commit 535fdfc5a2 ("arm64: Use load LSE atomics for the non-return
per-CPU atomic operations") to solve this issue, but it seems to have
caused a regression on the fentry benchmark.

Using the fentry benchmark from the bpf selftests shows the following:

  ./tools/testing/selftests/bpf/bench trig-fentry

 +---------------------------------------------+------------------------+
 |               Configuration                 | Total Operations (M/s) |
 +---------------------------------------------+------------------------+
 | bpf-next/master with Catalin’s fix reverted |         51.770         |
 |---------------------------------------------|------------------------|
 | bpf-next/master                             |         43.271         |
 | bpf-next/master with this change            |         43.271         |
 +---------------------------------------------+------------------------+

All benchmarks were run on a KVM based vm with Neoverse-V2 and 8 cpus.

This patch yields a 25% improvement in this benchmark compared to
bpf-next. Notably, reverting Catalin's fix also results in a performance
gain for this benchmark, which is interesting but expected.

For completeness, this benchmark was also run with the change enabled on
x86-64, which resulted in a 30% regression in the fentry benchmark. So,
it is only enabled on arm64.

P.S. - Here is more data with other program types:

 +-----------------+-----------+-----------+----------+
 |     Metric      |  Before   |   After   | % Diff   |
 +-----------------+-----------+-----------+----------+
 | fentry          |   43.149  |   53.948  | +25.03%  |
 | fentry.s        |   41.831  |   50.937  | +21.76%  |
 | rawtp           |   50.834  |   58.731  | +15.53%  |
 | fexit           |   31.118  |   34.360  | +10.42%  |
 | tp              |   39.536  |   41.632  |  +5.30%  |
 | syscall-count   |    8.053  |    8.305  |  +3.13%  |
 | fmodret         |   33.940  |   34.769  |  +2.44%  |
 | kprobe          |    9.970  |    9.998  |  +0.28%  |
 | usermode-count  |  224.886  |  224.839  |  -0.02%  |
 | kernel-count    |  154.229  |  153.043  |  -0.77%  |
 +-----------------+-----------+-----------+----------+

[1] https://lore.kernel.org/all/e7d539ed-ced0-4b96-8ecd-048a5b803b85@paulmck-laptop/
====================

Link: https://patch.msgid.link/20251219184422.2899902-1-puranjay@kernel.org
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
2025-12-21 10:54:37 -08:00
Puranjay Mohan
c3e34f88f9 bpf: arm64: Optimize recursion detection by not using atomics
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>
2025-12-21 10:54:37 -08:00
Puranjay Mohan
93f0d09697 bpf: move recursion detection logic to helpers
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>
2025-12-21 10:54:37 -08:00
Andrii Nakryiko
3d60306b7b Merge branch 'resolve_btfids-support-for-btf-modifications'
Ihor Solodrai says:

====================
resolve_btfids: Support for BTF modifications

This series changes resolve_btfids and kernel build scripts to enable
BTF transformations in resolve_btfids. Main motivation for enhancing
resolve_btfids is to reduce dependency of the kernel build on pahole
capabilities [1] and enable BTF features and optimizations [2][3]
particular to the kernel.

Patches #1-#4 in the series are non-functional changes in
resolve_btfids.

Patch #5 makes kernel build notice pahole version changes between
builds.

Patch #6 changes minimum version of pahole required for
CONFIG_DEBUG_INFO_BTF to v1.22

Patch #7 makes a small prep change in selftests/bpf build.

The last patch (#8) makes significant changes in resolve_btfids and
introduces scripts/gen-btf.sh. See implementation details in the patch
description.

Successful BPF CI run: https://github.com/kernel-patches/bpf/actions/runs/20378061470

[1] https://lore.kernel.org/dwarves/ba1650aa-fafd-49a8-bea4-bdddee7c38c9@linux.dev/
[2] https://lore.kernel.org/bpf/20251029190113.3323406-1-ihor.solodrai@linux.dev/
[3] https://lore.kernel.org/bpf/20251119031531.1817099-1-dolinux.peng@gmail.com/
---

v6->v7:
  - documentation edits in patches #5 and #6 (Nicolas)

v6: https://lore.kernel.org/bpf/20251219020006.785065-1-ihor.solodrai@linux.dev/

v5->v6:
  - patch #8: fix double free when btf__distill_base fails (reported by AI)
    https://lore.kernel.org/bpf/e269870b8db409800045ee0061fc02d21721e0efadd99ca83960b48f8db7b3f3@mail.kernel.org/

v5: https://lore.kernel.org/bpf/20251219003147.587098-1-ihor.solodrai@linux.dev/

v4->v5:
  - patch #3: fix an off-by-one bug (reported by AI)
    https://lore.kernel.org/bpf/106b6e71bce75b8f12a85f2f99e75129e67af7287f6d81fa912589ece14044f9@mail.kernel.org/
  - patch #8: cleanup GEN_BTF in Makefile.btf

v4: https://lore.kernel.org/bpf/20251218003314.260269-1-ihor.solodrai@linux.dev/

v3->v4:
  - add patch #4: "resolve_btfids: Always build with -Wall -Werror"
  - add patch #5: "kbuild: Sync kconfig when PAHOLE_VERSION changes" (Alan)
  - fix clang cross-compilation (LKP)
    https://lore.kernel.org/bpf/cecb6351-ea9a-4f8a-863a-82c9ef02f012@linux.dev/
  - remove GEN_BTF env variable (Andrii)
  - nits and cleanup in resolve_btfids/main.c (Andrii, Eduard)
  - nits in a patch bumping minimum pahole version (Andrii, AI)

v3: https://lore.kernel.org/bpf/20251205223046.4155870-1-ihor.solodrai@linux.dev/

v2->v3:
  - add patch #4 bumping minimum pahole version (Andrii, Alan)
  - add patch #5 pre-fixing resolve_btfids test (Donglin)
  - add GEN_BTF var and assemble RESOLVE_BTFIDS_FLAGS in Makefile.btf (Alan)
  - implement --distill_base flag in resolve_btfids, set it depending
    on KBUILD_EXTMOD in Makefile.btf (Eduard)
  - various implementation nits, see the v2 thread for details (Andrii, Eduard)

v2: https://lore.kernel.org/bpf/20251127185242.3954132-1-ihor.solodrai@linux.dev/

v1->v2:
  - gen-btf.sh and other shell script fixes (Donglin)
  - update selftests build (Donglin)
  - generate .BTF.base only when KBUILD_EXTMOD is set (Alan)
  - proper endianness handling for cross-compilation
  - change elf_begin mode from ELF_C_RDWR_MMAP to ELF_C_READ_MMAP_PRIVATE
  - remove compressed_section_fix()
  - nit NULL check in patch #3 (suggested by AI)

v1: https://lore.kernel.org/bpf/20251126012656.3546071-1-ihor.solodrai@linux.dev/
====================

Link: https://patch.msgid.link/20251219181321.1283664-1-ihor.solodrai@linux.dev
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
2025-12-19 10:55:41 -08:00
Ihor Solodrai
522397d05e resolve_btfids: Change in-place update with raw binary output
Currently resolve_btfids updates .BTF_ids section of an ELF file
in-place, based on the contents of provided BTF, usually within the
same input file, and optionally a BTF base.

Change resolve_btfids behavior to enable BTF transformations as part
of its main operation. To achieve this, in-place ELF write in
resolve_btfids is replaced with generation of the following binaries:
  * ${1}.BTF with .BTF section data
  * ${1}.BTF_ids with .BTF_ids section data if it existed in ${1}
  * ${1}.BTF.base with .BTF.base section data for out-of-tree modules

The execution of resolve_btfids and consumption of its output is
orchestrated by scripts/gen-btf.sh introduced in this patch.

The motivation for emitting binary data is that it allows simplifying
resolve_btfids implementation by delegating ELF update to the $OBJCOPY
tool [1], which is already widely used across the codebase.

There are two distinct paths for BTF generation and resolve_btfids
application in the kernel build: for vmlinux and for kernel modules.

For the vmlinux binary a .BTF section is added in a roundabout way to
ensure correct linking. The patch doesn't change this approach, only
the implementation is a little different.

Before this patch it worked as follows:

  * pahole consumed .tmp_vmlinux1 [2] and added .BTF section with
    llvm-objcopy [3] to it
  * then everything except the .BTF section was stripped from .tmp_vmlinux1
    into a .tmp_vmlinux1.bpf.o object [2], later linked into vmlinux
  * resolve_btfids was executed later on vmlinux.unstripped [4],
    updating it in-place

After this patch gen-btf.sh implements the following:

  * pahole consumes .tmp_vmlinux1 and produces a *detached* file with
    raw BTF data
  * resolve_btfids consumes .tmp_vmlinux1 and detached BTF to produce
    (potentially modified) .BTF, and .BTF_ids sections data
  * a .tmp_vmlinux1.bpf.o object is then produced with objcopy copying
    BTF output of resolve_btfids
  * .BTF_ids data gets embedded into vmlinux.unstripped in
    link-vmlinux.sh by objcopy --update-section

For kernel modules, creating a special .bpf.o file is not necessary,
and so embedding of sections data produced by resolve_btfids is
straightforward with objcopy.

With this patch an ELF file becomes effectively read-only within
resolve_btfids, which allows deleting elf_update() call and satellite
code (like compressed_section_fix [5]).

Endianness handling of .BTF_ids data is also changed. Previously the
"flags" part of the section was bswapped in sets_patch() [6], and then
Elf_Type was modified before elf_update() to signal to libelf that
bswap may be necessary. With this patch we explicitly bswap entire
data buffer on load and on dump.

[1] https://lore.kernel.org/bpf/131b4190-9c49-4f79-a99d-c00fac97fa44@linux.dev/
[2] https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/tree/scripts/link-vmlinux.sh?h=v6.18#n110
[3] https://git.kernel.org/pub/scm/devel/pahole/pahole.git/tree/btf_encoder.c?h=v1.31#n1803
[4] https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/tree/scripts/link-vmlinux.sh?h=v6.18#n284
[5] https://lore.kernel.org/bpf/20200819092342.259004-1-jolsa@kernel.org/
[6] https://lore.kernel.org/bpf/cover.1707223196.git.vmalik@redhat.com/

Signed-off-by: Ihor Solodrai <ihor.solodrai@linux.dev>
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Tested-by: Alan Maguire <alan.maguire@oracle.com>
Acked-by: Eduard Zingerman <eddyz87@gmail.com>
Link: https://lore.kernel.org/bpf/20251219181825.1289460-3-ihor.solodrai@linux.dev
2025-12-19 10:55:40 -08:00
Ihor Solodrai
014e1cdb5f selftests/bpf: Run resolve_btfids only for relevant .test.o objects
A selftest targeting resolve_btfids functionality relies on a resolved
.BTF_ids section to be available in the TRUNNER_BINARY. The underlying
BTF data is taken from a special BPF program (btf_data.c), and so
resolve_btfids is executed as a part of a TRUNNER_BINARY build recipe
on the final binary.

Subsequent patches in this series allow resolve_btfids to modify BTF
before resolving the symbols, which means that the test needs access
to that modified BTF [1]. Currently the test simply reads in
btf_data.bpf.o on the assumption that BTF hasn't changed.

Implement resolve_btfids call only for particular test objects (just
resolve_btfids.test.o for now). The test objects are linked into the
TRUNNER_BINARY, and so .BTF_ids section will be available there.

This will make it trivial for the resolve_btfids test to access BTF
modified by resolve_btfids.

[1] https://lore.kernel.org/bpf/CAErzpmvsgSDe-QcWH8SFFErL6y3p3zrqNri5-UHJ9iK2ChyiBw@mail.gmail.com/

Signed-off-by: Ihor Solodrai <ihor.solodrai@linux.dev>
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Tested-by: Alan Maguire <alan.maguire@oracle.com>
Acked-by: Eduard Zingerman <eddyz87@gmail.com>
Link: https://lore.kernel.org/bpf/20251219181825.1289460-2-ihor.solodrai@linux.dev
2025-12-19 10:55:40 -08:00
Ihor Solodrai
903922cfa0 lib/Kconfig.debug: Set the minimum required pahole version to v1.22
Subsequent patches in the series change vmlinux linking scripts to
unconditionally pass --btf_encode_detached to pahole, which was
introduced in v1.22 [1][2].

This change allows to remove PAHOLE_HAS_SPLIT_BTF Kconfig option and
other checks of older pahole versions.

[1] https://github.com/acmel/dwarves/releases/tag/v1.22
[2] https://lore.kernel.org/bpf/cbafbf4e-9073-4383-8ee6-1353f9e5869c@oracle.com/

Signed-off-by: Ihor Solodrai <ihor.solodrai@linux.dev>
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Tested-by: Alan Maguire <alan.maguire@oracle.com>
Acked-by: Eduard Zingerman <eddyz87@gmail.com>
Acked-by: Nicolas Schier <nsc@kernel.org>
Link: https://lore.kernel.org/bpf/20251219181825.1289460-1-ihor.solodrai@linux.dev
2025-12-19 10:55:40 -08:00
Ihor Solodrai
90e5b38a26 kbuild: Sync kconfig when PAHOLE_VERSION changes
This patch implements kconfig re-sync when the pahole version changes
between builds, similar to how it happens for compiler version change
via CC_VERSION_TEXT.

Define PAHOLE_VERSION in the top-level Makefile and export it for
config builds. Set CONFIG_PAHOLE_VERSION default to the exported
variable.

Kconfig records the PAHOLE_VERSION value in
include/config/auto.conf.cmd [1].

The Makefile includes auto.conf.cmd, so if PAHOLE_VERSION changes
between builds, make detects a dependency change and triggers
syncconfig to update the kconfig [2].

For external module builds, add a warning message in the prepare
target, similar to the existing compiler version mismatch warning.

Note that if pahole is not installed or available, PAHOLE_VERSION is
set to 0 by pahole-version.sh, so the (un)installation of pahole is
treated as a version change.

See previous discussions for context [3].

[1] https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/tree/scripts/kconfig/preprocess.c?h=v6.18#n91
[2] https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/tree/Makefile?h=v6.18#n815
[3] https://lore.kernel.org/bpf/8f946abf-dd88-4fac-8bb4-84fcd8d81cf0@oracle.com/

Signed-off-by: Ihor Solodrai <ihor.solodrai@linux.dev>
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Tested-by: Nicolas Schier <nsc@kernel.org>
Tested-by: Alan Maguire <alan.maguire@oracle.com>
Reviewed-by: Nicolas Schier <nsc@kernel.org>
Link: https://lore.kernel.org/bpf/20251219181321.1283664-6-ihor.solodrai@linux.dev
2025-12-19 10:55:40 -08:00
Ihor Solodrai
fb348d4fdf resolve_btfids: Always build with -Wall -Werror
resolve_btfids builds without compiler warnings currently, so let's
enforce this for future changes with '-Wall -Werror' flags [1].

[1] https://lore.kernel.org/bpf/1957a60b-6c45-42a7-b525-a6e335a735ff@linux.dev/

Signed-off-by: Ihor Solodrai <ihor.solodrai@linux.dev>
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Tested-by: Alan Maguire <alan.maguire@oracle.com>
Link: https://lore.kernel.org/bpf/20251219181321.1283664-5-ihor.solodrai@linux.dev
2025-12-19 10:55:40 -08:00
Ihor Solodrai
a4fa885bd5 resolve_btfids: Introduce enum btf_id_kind
Instead of using multiple flags, make struct btf_id tagged with an
enum value indicating its kind in the context of resolve_btfids.

Signed-off-by: Ihor Solodrai <ihor.solodrai@linux.dev>
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Tested-by: Alan Maguire <alan.maguire@oracle.com>
Acked-by: Eduard Zingerman <eddyz87@gmail.com>
Link: https://lore.kernel.org/bpf/20251219181321.1283664-4-ihor.solodrai@linux.dev
2025-12-19 10:55:40 -08:00
Ihor Solodrai
5f347a0f78 resolve_btfids: Factor out load_btf()
Increase the lifetime of parsed BTF in resolve_btfids by factoring
load_btf() routine out of symbols_resolve() and storing the base_btf
and btf pointers in the struct object.

Signed-off-by: Ihor Solodrai <ihor.solodrai@linux.dev>
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Tested-by: Alan Maguire <alan.maguire@oracle.com>
Acked-by: Eduard Zingerman <eddyz87@gmail.com>
Link: https://lore.kernel.org/bpf/20251219181321.1283664-3-ihor.solodrai@linux.dev
2025-12-19 10:55:40 -08:00
Ihor Solodrai
c1c7d61746 resolve_btfids: Rename object btf field to btf_path
Rename the member of `struct object` holding the path to BTF data if
provided via --btf arg. `btf_path` is less ambiguous.

Signed-off-by: Ihor Solodrai <ihor.solodrai@linux.dev>
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Tested-by: Alan Maguire <alan.maguire@oracle.com>
Acked-by: Eduard Zingerman <eddyz87@gmail.com>
Link: https://lore.kernel.org/bpf/20251219181321.1283664-2-ihor.solodrai@linux.dev
2025-12-19 10:55:39 -08:00
Alexei Starovoitov
ec439c3801 Merge git://git.kernel.org/pub/scm/linux/kernel/git/bpf/bpf after 6.19-rc1
Cross-merge BPF and other fixes after downstream PR.

Signed-off-by: Alexei Starovoitov <ast@kernel.org>
2025-12-16 21:29:38 -08:00
Linus Torvalds
ea1013c153 bpf-fixes
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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
2025-12-17 15:54:58 +12:00
Linus Torvalds
64e68f8a95 s390 fixes for 6.19-rc2
- clear 'Search boot program' flag when 'bootprog' sysfs file is
   written to override a value set from Hardware Management Console
 
 - fix cyclic dead-lock in zpci_zdev_put() and zpci_scan_devices()
   functions when triggering PCI device recovery using sysfs
 
 - annotate the expected lock context imbalance in zpci_release_device()
   function to fix a sparse complaint
 
 - fix the logic to fallback to the return address register value in
   the topmost frame when stack tracing uses a back chain
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Merge tag 's390-6.19-3' of git://git.kernel.org/pub/scm/linux/kernel/git/s390/linux

Pull s390 fixes from Alexander Gordeev:

 - clear 'Search boot program' flag when 'bootprog' sysfs file is
   written to override a value set from Hardware Management Console

 - fix cyclic dead-lock in zpci_zdev_put() and zpci_scan_devices()
   functions when triggering PCI device recovery using sysfs

 - annotate the expected lock context imbalance in zpci_release_device()
   function to fix a sparse complaint

 - fix the logic to fallback to the return address register value in the
   topmost frame when stack tracing uses a back chain

* tag 's390-6.19-3' of git://git.kernel.org/pub/scm/linux/kernel/git/s390/linux:
  s390/stacktrace: Do not fallback to RA register
  s390/pci: Annotate lock context imbalance in zpci_release_device()
  s390/pci: Fix cyclic dead-lock in zpci_zdev_put() and zpci_scan_devices()
  s390/ipl: Clear SBP flag when bootprog is set
2025-12-17 15:48:30 +12:00
Andrii Nakryiko
e7a0adb03d Merge branch 'libbpf-move-arena-variables-out-of-the-zero-page'
Emil Tsalapatis says:

====================
libbpf: move arena variables out of the zero page

Modify libbpf to place arena globals at the end of the arena mapping
instead of the very beginning. This allows programs to leave the
"zero page" of the arena unmapped, so that NULL arena pointer
dereferences trigger a page fault and associated backtrace in BPF streams.
In contrast, the current policy of placing global data in the zero pages
means that NULL dereferences silently corrupt global data, e.g, arena
qspinlock state. This makes arena bugs more difficult to debug.

The patchset adds code to libbpf to move global arena data to the end of
the arena. At load time, libbpf adjusts each symbol's location within
the arena to point to the right location in the arena. The patchset
also adjusts the arena skeleton pointer to point to the arena globals,
now that they are not in the beginning of the arena region.

CHANGESET
=========

v3->v4: (https://lore.kernel.org/bpf/20251215161313.10120-1-emil@etsalapatis.com/T/#t)

- Added Acks by Eduard
- Changed jumptable sym_off to unsigned int for consistency (AI)
- Adjusted selftests to ensure arena globals are actually mapped in (Eduard)
- (Patch 2) Adjusted selftests that were failing because they were expecting the
  now removed "direct map offset" error message

v2->v3: (https://lore.kernel.org/bpf/20251203162625.13152-1-emil@etsalapatis.com/)

- Remove unnecessary kernel bounds check in resolve_pseudo_ldimm64
  (Andrii)
- Added patch to turn sym_off unsigned to prevent overflow (AI)
- Remove obsolete references to offsets from test patch description
  (Andrii)
- Use size_t for arena_data_off (Andrii)
- Remove extra mutable variable from offset calculations (Andrii)

v1->v2: (https://lore.kernel.org/bpf/20251118030058.162967-1-emil@etsalapatis.com)

- Moved globals to the end of the mapping: (Andrii)
	- Removed extra parameter for offset and parameter picking logic
	- Removed padding in the skeleton
	- Removed additional libbpf call
- Added Reviewed-by from Eduard on patch 1

Signed-off-by: Emil Tsalapatis <emil@etsalapatis.com>
====================

Link: https://patch.msgid.link/20251216173325.98465-1-emil@etsalapatis.com
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
2025-12-16 10:42:56 -08:00
Emil Tsalapatis
19f12431b6 selftests/bpf: Add tests for the arena offset of globals
Add tests for the new libbpf globals arena offset logic. The
tests cover the case of globals being as large as the arena
itself, and being smaller than the arena. In that case, the
data is placed at the end of the arena, and the beginning
of the arena is free.

Signed-off-by: Emil Tsalapatis <emil@etsalapatis.com>
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Link: https://lore.kernel.org/bpf/20251216173325.98465-6-emil@etsalapatis.com
2025-12-16 10:42:55 -08:00
Emil Tsalapatis
c1f61171d4 libbpf: Move arena globals to the end of the arena
Arena globals are currently placed at the beginning of the arena
by libbpf. This is convenient, but prevents users from reserving
guard pages in the beginning of the arena to identify NULL pointer
dereferences. Adjust the load logic to place the globals at the
end of the arena instead.

Also modify bpftool to set the arena pointer in the program's BPF
skeleton to point to the globals. Users now call bpf_map__initial_value()
to find the beginning of the arena mapping and use the arena pointer
in the skeleton to determine which part of the mapping holds the
arena globals and which part is free.

Suggested-by: Andrii Nakryiko <andrii@kernel.org>
Signed-off-by: Emil Tsalapatis <emil@etsalapatis.com>
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Acked-by: Eduard Zingerman <eddyz87@gmail.com>
Link: https://lore.kernel.org/bpf/20251216173325.98465-5-emil@etsalapatis.com
2025-12-16 10:42:55 -08:00
Emil Tsalapatis
0aa721437e libbpf: Turn relo_core->sym_off unsigned
The symbols' relocation offsets in BPF are stored in an int field,
but cannot actually be negative. When in the next patch libbpf relocates
globals to the end of the arena, it is also possible to have valid
offsets > 2GiB that are used to calculate the final relo offsets.
Avoid accidentally interpreting large offsets as negative by turning
the sym_off field unsigned.

Signed-off-by: Emil Tsalapatis <emil@etsalapatis.com>
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Acked-by: Eduard Zingerman <eddyz87@gmail.com>
Link: https://lore.kernel.org/bpf/20251216173325.98465-4-emil@etsalapatis.com
2025-12-16 10:42:55 -08:00
Emil Tsalapatis
12a1fe6e12 bpf/verifier: Do not limit maximum direct offset into arena map
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
2025-12-16 10:42:55 -08:00
Emil Tsalapatis
0355911ac0 selftests/bpf: Explicitly account for globals in verifier_arena_large
The big_alloc1 test in verifier_arena_large assumes that the arena base
and the first page allocated by bpf_arena_alloc_pages are identical.
This is not the case, because the first page in the arena is populated
by global arena data. The test still passes because the code makes the
tacit assumption that the first page is on offset PAGE_SIZE instead of
0.

Make this distinction explicit in the code, and adjust the page offsets
requested during the test to count from the beginning of the arena
instead of using the address of the first allocated page.

Signed-off-by: Emil Tsalapatis <emil@etsalapatis.com>
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Reviewed-by: Eduard Zingerman <eddyz87@gmail.com>
Link: https://lore.kernel.org/bpf/20251216173325.98465-2-emil@etsalapatis.com
2025-12-16 10:42:55 -08:00
Linus Torvalds
40fbbd64bb a couple of shmem rename fixes - recent regression from tree-in-dcache
series and older breakage from stable directory offsets stuff.
 
 Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
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Merge tag 'pull-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs

Pull shmem rename fixes from Al Viro:
 "A couple of shmem rename fixes - recent regression from tree-in-dcache
  series and older breakage from stable directory offsets stuff"

* tag 'pull-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs:
  shmem: fix recovery on rename failures
  shmem_whiteout(): fix regression from tree-in-dcache series
2025-12-16 19:44:36 +12:00
Linus Torvalds
53ec4a79ff seven smb3 server fixes
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Merge tag 'v6.19-rc1-ksmbd-server-fixes' of git://git.samba.org/ksmbd

Pull smb server fixes from Steve French:

 - Fix set xattr name validation

 - Fix session refcount leak

 - Minor cleanup

 - smbdirect (RDMA) fixes: improve receive completion, and connect

* tag 'v6.19-rc1-ksmbd-server-fixes' of git://git.samba.org/ksmbd:
  ksmbd: fix buffer validation by including null terminator size in EA length
  ksmbd: Fix refcount leak when invalid session is found on session lookup
  ksmbd: remove redundant DACL check in smb_check_perm_dacl
  ksmbd: convert comma to semicolon
  smb: server: defer the initial recv completion logic to smb_direct_negotiate_recv_work()
  smb: server: initialize recv_io->cqe.done = recv_done just once
  smb: smbdirect: introduce smbdirect_socket.connect.{lock,work}
2025-12-16 19:34:09 +12:00
Linus Torvalds
115fada16b for-6.19-rc1-tag
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Merge tag 'for-6.19-rc1-tag' of git://git.kernel.org/pub/scm/linux/kernel/git/kdave/linux

Pull btrfs fixes from David Sterba:

 - fix missing btrfs_path release after printing a relocation error
   message

 - fix extent changeset leak on mmap write after failure to reserve
   metadata

 - fix fs devices list structure freeing, it could be potentially leaked
   under some circumstances

 - tree log fixes:
     - fix incremental directory logging where inodes for new dentries
       were incorrectly skipped
     - don't log conflicting inode if it's a directory moved in the
       current transaction

 - regression fixes:
     - fix incorrect btrfs_path freeing when it's auto-cleaned
     - revert commit simplifying preallocation of temporary structures
       in qgroup functions, some cases were not handled properly

* tag 'for-6.19-rc1-tag' of git://git.kernel.org/pub/scm/linux/kernel/git/kdave/linux:
  btrfs: fix changeset leak on mmap write after failure to reserve metadata
  btrfs: fix memory leak of fs_devices in degraded seed device path
  btrfs: fix a potential path leak in print_data_reloc_error()
  Revert "btrfs: add ASSERTs on prealloc in qgroup functions"
  btrfs: do not skip logging new dentries when logging a new name
  btrfs: don't log conflicting inode if it's a dir moved in the current transaction
  btrfs: tests: fix double btrfs_path free in remove_extent_ref()
2025-12-16 19:28:20 +12:00
Linus Torvalds
dbf89321bf sched_ext: Fixes for v6.19-rc1
- Fix memory leak when destroying helper kthread workers during scheduler
   disable.
 
 - Fix bypass depth accounting on scx_enable() failure which could leave
   the system permanently in bypass mode.
 
 - Fix missing preemption handling when moving tasks to local DSQs via
   scx_bpf_dsq_move().
 
 - Misc fixes including NULL check for put_prev_task(), flushing stdout in
   selftests, and removing unused code.
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Merge tag 'sched_ext-for-6.19-rc1-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/tj/sched_ext

Pull sched_ext fixes from Tejun Heo:

 - Fix memory leak when destroying helper kthread workers during
   scheduler disable

 - Fix bypass depth accounting on scx_enable() failure which could leave
   the system permanently in bypass mode

 - Fix missing preemption handling when moving tasks to local DSQs via
   scx_bpf_dsq_move()

 - Misc fixes including NULL check for put_prev_task(), flushing stdout
   in selftests, and removing unused code

* tag 'sched_ext-for-6.19-rc1-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/tj/sched_ext:
  sched_ext: Remove unused code in the do_pick_task_scx()
  selftests/sched_ext: flush stdout before test to avoid log spam
  sched_ext: Fix missing post-enqueue handling in move_local_task_to_local_dsq()
  sched_ext: Factor out local_dsq_post_enq() from dispatch_enqueue()
  sched_ext: Fix bypass depth leak on scx_enable() failure
  sched/ext: Avoid null ptr traversal when ->put_prev_task() is called with NULL next
  sched_ext: Fix the memleak for sch->helper objects
2025-12-16 19:24:35 +12:00
Linus Torvalds
6b63f90fa2 cgroup: Fixes for v6.19-rc1
- Fix a race condition in css_rstat_updated() where CMPXCHG without LOCK
   prefix could cause lnode corruption when the flusher runs concurrently
   on another CPU. The issue was introduced in 6.17 and causes memcg stats
   to become corrupted in production.
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Merge tag 'cgroup-for-6.19-rc1-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/tj/cgroup

Pull cgroup fix from Tejun Heo:

 - Fix a race condition in css_rstat_updated() where CMPXCHG without
   LOCK prefix could cause lnode corruption when the flusher runs
   concurrently on another CPU. The issue was introduced in 6.17 and
   causes memcg stats to become corrupted in production.

* tag 'cgroup-for-6.19-rc1-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/tj/cgroup:
  cgroup: rstat: use LOCK CMPXCHG in css_rstat_updated
2025-12-16 19:21:17 +12:00
Al Viro
e1b4c6a583 shmem: fix recovery on rename failures
maple_tree insertions can fail if we are seriously short on memory;
simple_offset_rename() does not recover well if it runs into that.
The same goes for simple_offset_rename_exchange().

Moreover, shmem_whiteout() expects that if it succeeds, the caller will
progress to d_move(), i.e. that shmem_rename2() won't fail past the
successful call of shmem_whiteout().

Not hard to fix, fortunately - mtree_store() can't fail if the index we
are trying to store into is already present in the tree as a singleton.

For simple_offset_rename_exchange() that's enough - we just need to be
careful about the order of operations.

For simple_offset_rename() solution is to preinsert the target into the
tree for new_dir; the rest can be done without any potentially failing
operations.

That preinsertion has to be done in shmem_rename2() rather than in
simple_offset_rename() itself - otherwise we'd need to deal with the
possibility of failure after successful shmem_whiteout().

Fixes: a2e459555c ("shmem: stable directory offsets")
Reviewed-by: Christian Brauner <brauner@kernel.org>
Reviewed-by: Chuck Lever <chuck.lever@oracle.com>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2025-12-16 00:57:29 -05:00
Zqiang
bb27226f0d sched_ext: Remove unused code in the do_pick_task_scx()
The kick_idle variable is no longer used, this commit therefore remove
it and also remove associated code in the do_pick_task_scx().

Signed-off-by: Zqiang <qiang.zhang@linux.dev>
Reviewed-by: Andrea Righi <arighi@nvidia.com>
Reviewed-by: Emil Tsalapatis <emil@etsalapatis.com>
Signed-off-by: Tejun Heo <tj@kernel.org>
2025-12-15 05:53:49 -10:00
Namjae Jeon
95d7a890e4 ksmbd: fix buffer validation by including null terminator size in EA length
The smb2_set_ea function, which handles Extended Attributes (EA),
was performing buffer validation checks that incorrectly omitted the size
of the null terminating character (+1 byte) for EA Name.
This patch fixes the issue by explicitly adding '+ 1' to EaNameLength where
the null terminator is expected to be present in the buffer, ensuring
the validation accurately reflects the total required buffer size.

Cc: stable@vger.kernel.org
Reported-by: Roger <roger.andersen@protonmail.com>
Reported-by: Stanislas Polu <spolu@dust.tt>
Signed-off-by: Namjae Jeon <linkinjeon@kernel.org>
Signed-off-by: Steve French <stfrench@microsoft.com>
2025-12-14 18:35:56 -06:00
Namjae Jeon
cafb57f7bd ksmbd: Fix refcount leak when invalid session is found on session lookup
When a session is found but its state is not SMB2_SESSION_VALID, It
indicates that no valid session was found, but it is missing to decrement
the reference count acquired by the session lookup, which results in
a reference count leak. This patch fixes the issue by explicitly calling
ksmbd_user_session_put to release the reference to the session.

Cc: stable@vger.kernel.org
Reported-by: Alexandre <roger.andersen@protonmail.com>
Reported-by: Stanislas Polu <spolu@dust.tt>
Signed-off-by: Namjae Jeon <linkinjeon@kernel.org>
Signed-off-by: Steve French <stfrench@microsoft.com>
2025-12-14 18:35:56 -06:00
Alexey Velichayshiy
8dd2e58b62 ksmbd: remove redundant DACL check in smb_check_perm_dacl
A zero value of pdacl->num_aces is already handled at the start of
smb_check_perm_dacl() so the second check is useless.

Drop the unreachable code block, no functional impact intended.

Found by Linux Verification Center (linuxtesting.org) with SVACE.

Signed-off-by: Alexey Velichayshiy <a.velichayshiy@ispras.ru>
Acked-by: Namjae Jeon <linkinjeon@kernel.org>
Signed-off-by: Steve French <stfrench@microsoft.com>
2025-12-14 18:35:56 -06:00
Chen Ni
0446356e9f ksmbd: convert comma to semicolon
Replace comma between expressions with semicolons.

Using a ',' in place of a ';' can have unintended side effects.
Although that is not the case here, it is seems best to use ';'
unless ',' is intended.

Found by inspection.
No functional change intended.
Compile tested only.

Signed-off-by: Chen Ni <nichen@iscas.ac.cn>
Acked-by: Namjae Jeon <linkinjeon@kernel.org>
Signed-off-by: Steve French <stfrench@microsoft.com>
2025-12-14 18:35:56 -06:00
Stefan Metzmacher
d180b1d9c7 smb: server: defer the initial recv completion logic to smb_direct_negotiate_recv_work()
The previous change to relax WARN_ON_ONCE(SMBDIRECT_SOCKET_*) checks in
recv_done() and smb_direct_cm_handler() seems to work around the
problem that the order of initial recv completion and
RDMA_CM_EVENT_ESTABLISHED is random, but it's still
a bit ugly.

This implements a better solution deferring the recv completion
processing to smb_direct_negotiate_recv_work(), which is queued
only if both events arrived.

In order to avoid more basic changes to the main recv_done
callback, I introduced a smb_direct_negotiate_recv_done,
which is only used for the first pdu, this will allow
further cleanup and simplifications in recv_done
as a future patch.

smb_direct_negotiate_recv_work() is also very basic
with only basic error checking and the transition
from SMBDIRECT_SOCKET_NEGOTIATE_NEEDED to
SMBDIRECT_SOCKET_NEGOTIATE_RUNNING, which allows
smb_direct_prepare() to continue as before.

Cc: Tom Talpey <tom@talpey.com>
Cc: linux-cifs@vger.kernel.org
Cc: samba-technical@lists.samba.org
Signed-off-by: Stefan Metzmacher <metze@samba.org>
Acked-by: Namjae Jeon <linkinjeon@kernel.org>
Signed-off-by: Steve French <stfrench@microsoft.com>
2025-12-14 18:35:55 -06:00
Stefan Metzmacher
c1fb124f2a smb: server: initialize recv_io->cqe.done = recv_done just once
smbdirect_recv_io structures are pre-allocated so we can set the
callback function just once.

This will make it easy to move smb_direct_post_recv to common code
soon.

Cc: Tom Talpey <tom@talpey.com>
Cc: linux-cifs@vger.kernel.org
Cc: samba-technical@lists.samba.org
Signed-off-by: Stefan Metzmacher <metze@samba.org>
Acked-by: Namjae Jeon <linkinjeon@kernel.org>
Signed-off-by: Steve French <stfrench@microsoft.com>
2025-12-14 18:35:55 -06:00