Commit Graph

3163 Commits

Author SHA1 Message Date
Linus Torvalds
9c87e61e3c Merge tag 'bpf-next-7.2' of git://git.kernel.org/pub/scm/linux/kernel/git/bpf/bpf-next
Pull bpf updates from Alexei Starovoitov:
 "Major changes:

   - Recover from BPF arena page faults using a scratch page and add
     ptep_try_set() for lockless empty-slot installs on x86 and arm64.

     This allows BPF kfuncs to access arena pointers directly.

     The 'arena_direct_access' stable branch was created for this work
     and was pulled into sched-ext and bpf-next trees (Tejun Heo, Kumar
     Kartikeya Dwivedi)

   - Lift old restriction and support 6+ arguments in BPF programs and
     kfuncs on x86 and arm64 (Yonghong Song, Puranjay Mohan)

  Other features and fixes:

   - Add 24-bit BTF vlen and reclaim unused bits in the BTF UAPI to ease
     addition of new BTF kinds (Alan Maguire)

   - Raise the maximum BPF call chain depth from 8 to 16 frames (Alexei
     Starovoitov)

   - Refactor object relationship tracking in the verifier and fix a
     dynptr use-after-free bug (Amery Hung)

   - Harden the signed program loader and reject exclusive maps as inner
     maps (Daniel Borkmann)

   - Replace the verifier min/max bounds fields with a circular number
     (cnum) representation and improve 32->64 bit range refinements
     (Eduard Zingerman)

   - Introduce the arena library and runtime (libarena) with a buddy
     allocator, rbtree and SPMC queue data structures, ASAN support and
     a parallel test harness. Allow subprograms to return arena pointers
     and switch to a BTF type-tag based __arena annotation (Emil
     Tsalapatis)

   - Cache build IDs in the sleepable stackmap path and avoid faultable
     build ID reads under mm locks (Ihor Solodrai)

   - Introduce the tracing_multi link to attach a single BPF program to
     many kernel functions at once. Allow specifying the uprobe_multi
     target via FD (Jiri Olsa)

   - Extend the bpf_list family of kfuncs with bpf_list_add/del(), and
     bpf_list_is_first/is_last/empty() (Kaitao Cheng)

   - Extend the BPF syscall with common attributes support for
     prog_load, btf_load and map_create (Leon Hwang)

   - Wrap rhashtable as BPF map (Mykyta Yatsenko, Herbert Xu)

   - Add sleepable support for tracepoint programs and fix deadlocks in
     LRU map due to NMI reentry (Mykyta Yatsenko)

   - Fix OOB access in bpf_flow_keys, fix nullness analysis of inner
     arrays, enforce write checks for global subprograms (Nuoqi Gui)

   - Report the maximum combined stack depth and print a breakdown of
     instructions processed per subprogram (Paul Chaignon)

   - Add an XDP load-balancer benchmark and arm64 JIT support for stack
     arguments (Puranjay Mohan)

   - Add kfuncs to traverse over wakeup_sources (Samuel Wu)

   - Allow sleepable BPF programs to use LPM trie maps directly (Vlad
     Poenaru)

   - Many more fixes and cleanups across the verifier, BTF, sockmap,
     devmap, bpffs, security hooks, s390/riscv/loongarch JITs,
     rqspinlock, libbpf, bpftool, selftests"

* tag 'bpf-next-7.2' of git://git.kernel.org/pub/scm/linux/kernel/git/bpf/bpf-next: (336 commits)
  selftests/bpf: Work around llvm stack overflow in crypto progs
  selftests/bpf: add test for bpf_msg_pop_data() overflow
  bpf, sockmap: fix integer overflow in bpf_msg_pop_data() bounds check
  sockmap: Fix use-after-free in udp_bpf_recvmsg()
  bpf, sockmap: keep sk_msg copy state in sync
  bpf, sockmap: Fix wrong rsge offset in bpf_msg_push_data()
  bpf, sockmap: reject overflowing copy + len in bpf_msg_push_data()
  selftsets/bpf: Retry map update on helper_fill_hashmap()
  selftests/bpf: Add test for sleepable lsm_cgroup rejection
  selftests/bpf: Add test to verify the fix for bpf_setsockopt() helper
  bpf: Fix bpf_get/setsockopt to tos for ipv4-mapped ipv6 socket
  selftests/bpf: Avoid static LLVM linking for cross builds
  selftests/bpf: Use common CFLAGS for urandom_read
  selftests/bpf: Initialize operation name before use
  tools/bpf: build: Append extra cflags
  libbpf: Initialize CFLAGS before including Makefile.include
  bpftool: Append extra host flags
  bpftool: Avoid adding EXTRA_CFLAGS to HOST_CFLAGS
  bpftool: Pass host flags to bootstrap libbpf
  selftests/bpf: correct CONFIG_PPC64 macro name in comment
  ...
2026-06-17 09:18:14 +01:00
Linus Torvalds
6b5a2b7d9b Merge tag 'trace-tools-v7.2' of git://git.kernel.org/pub/scm/linux/kernel/git/trace/linux-trace
Pull RTLA tool updates from Steven Rostedt:

 - Fix discrepancy in --dump-tasks option

   Due to a mistake, rtla-timerlat-hist used the CLI syntax
   "--dump-task" instead of the documented "--dump-tasks". Change the
   option to match both documentation and the other timerlat tool,
   rtla-timerlat-top.

 - Extend coverage of runtime tests

   Cover both top and hist tools in all applicable test cases, add tests
   for a few uncovered options, and extend checks for some existing
   tests.

 - Add unit tests for actions

   rtla's actions feature is implemented in its source file and contains
   non-trivial parsing logic. Cover it with unit tests.

 - Stop record trace on interrupt

   Fix a bug where an interval exists after receiving a signal in which
   the main instance is stopped but the record instance is not, leading
   to discrepancies in reported results and sometimes rtla hanging.

 - Restore continue flag in actions_perform()

   Fix a bug where rtla always continues tracing after hitting a
   threshold even if the continue action was triggered just once, and
   add tests verifying that the flag is reset properly.

 - Migrate command line interface to libsubcmd

   Replace rtla's argument parsing using getopt_long() with libsubcmd,
   used by perf and objtool, to reuse existing code and auto-generate
   better help messages. Extensive unit tests are included to detect
   regressions.

 - Add -A/--aligned option to timerlat tools

   Add an option to align timerlat threads, based on the recently
   introduced TIMERLAT_ALIGN option of the timerlat tracer, together
   with unit tests and documentation.

 - Document tests in README

   Document how to run unit and runtime tests in rtla's README.txt,
   including the dependencies needed to run them.

* tag 'trace-tools-v7.2' of git://git.kernel.org/pub/scm/linux/kernel/git/trace/linux-trace: (26 commits)
  rtla: Document tests in README
  Documentation/rtla: Add -A/--aligned option
  rtla/tests: Add unit tests for -A/--aligned option
  rtla/timerlat: Add -A/--aligned CLI option
  rtla/tests: Add unit tests for CLI option callbacks
  rtla/tests: Add unit tests for _parse_args() functions
  rtla: Parse cmdline using libsubcmd
  tools subcmd: allow parsing distinct --opt and --no-opt
  tools subcmd: support optarg as separate argument
  rtla: Add libsubcmd dependency
  rtla/tests: Add runtime tests for restoring continue flag
  rtla/tests: Run runtime tests in temporary directory
  rtla/tests: Add unit test for restoring continue flag
  rtla/actions: Restore continue flag in actions_perform()
  rtla: Stop the record trace on interrupt
  rtla/tests: Add unit tests for actions module
  rtla/tests: Add runtime tests for -C/--cgroup
  rtla/tests: Add runtime test for -k and -u options
  rtla/tests: Add runtime test for -H/--house-keeping
  rtla/tests: Cover all hist options in runtime tests
  ...
2026-06-16 17:50:34 +05:30
Linus Torvalds
a87bbc4578 Merge tag 'docs-7.2' of git://git.kernel.org/pub/scm/linux/kernel/git/docs/linux
Pull documentation updates from Jonathan Corbet:
 "Things have calmed down a bit on the docs front, with no earthshaking
  changes this time around:

   - Ongoing work on the Japanese and Portuguese translations

   - Better integration of the MAINTAINERS file into the rendered
     documents, including a search interface

   - A seemingly infinite supply of fixes for typos, minor grammatical
     issues, and related problems that LLMs find with abandon"

* tag 'docs-7.2' of git://git.kernel.org/pub/scm/linux/kernel/git/docs/linux: (93 commits)
  docs: pt_BR: Translate 3.Early-stage.rst into Portuguese
  docs: pt_BR: update "Purpose of Defconfigs" section in maintainer-soc.rst
  Documentation: bug-hunting.rst: fix grammar
  docs/ja_JP: translate submitting-patches.rst (interleaved-replies)
  docs: Fix minor grammatical error
  docs/{it_it,sp_SP,zh_CN,zh_TW}: update references to removed CONFIG_DEBUG_SLAB
  Documentation: process: fix brackets
  Documentation: arch: fix brackets
  docs/dyndbg: explain flags parse 1st
  docs/dyndbg: update examples \012 to \n
  docs: kernel-parameters: Fix stale sticore file paths
  docs: real-time: Fix duplicated sched(7) text
  docs: kgdb: Fix stale source file paths
  docs: sonypi: Fix stale header file path
  docs: kernel-parameters: Remove sa1100ir IrDA parameter
  iommu: Documentation: rearrange, update kernel-parameters
  docs: md: fix grammar in speed_limit description
  docs: changes.rst: restore pahole 1.26 minimum (regressed by sort)
  Documentation: Fix syntax of kmalloc_objs example in coding style doc
  docs: pt_BR: update maintainer-handbooks
  ...
2026-06-16 08:35:59 +05:30
Leo Yan
f3846b3800 libbpf: Initialize CFLAGS before including Makefile.include
tools/scripts/Makefile.include may expand EXTRA_CFLAGS in a future
change.  This could alter the initialization of CFLAGS, as the default
options "-g -O2" would never be set once EXTRA_CFLAGS is expanded.

Prepare for this by moving the CFLAGS initialization before including
tools/scripts/Makefile.include, so it is not affected by the extended
EXTRA_CFLAGS.

Append EXTRA_CFLAGS to CFLAGS only after including Makefile.include and
place it last so that the extra flags propagate properly and can
override the default options.

tools/scripts/Makefile.include already appends $(CLANG_CROSS_FLAGS) to
CFLAGS, the Makefile appends $(CLANG_CROSS_FLAGS) again, remove the
redundant append.

Signed-off-by: Leo Yan <leo.yan@arm.com>
Acked-by: Ihor Solodrai <ihor.solodrai@linux.dev>
Link: https://lore.kernel.org/r/20260602-tools_build_fix_zero_init_bpf_only-v2-4-c76e5250ea1c@arm.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
2026-06-14 17:32:53 -07:00
Jiri Olsa
da3a4c3ec7 libbpf: Add path_fd to struct bpf_link_create_opts
Adding the path_fd field to struct bpf_link_create_opts and passing it
through kernel attr interface.

Assisted-by: Codex:GPT-5.4
Signed-off-by: Jiri Olsa <jolsa@kernel.org>
Link: https://lore.kernel.org/r/20260611114230.950379-5-jolsa@kernel.org
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
2026-06-14 17:24:25 -07:00
Jiri Olsa
f2aa370dfe libbpf: Add support to create tracing multi link
Adding bpf_program__attach_tracing_multi function for attaching
tracing program to multiple functions.

  struct bpf_link *
  bpf_program__attach_tracing_multi(const struct bpf_program *prog,
                                    const char *pattern,
                                    const struct bpf_tracing_multi_opts *opts);

User can specify functions to attach with 'pattern' argument that
allows wildcards (*?' supported) or provide BTF ids of functions
in array directly via opts argument. These options are mutually
exclusive.

When using BTF ids, user can also provide cookie value for each
provided id/function, that can be retrieved later in bpf program
with bpf_get_attach_cookie helper. Each cookie value is paired with
provided BTF id with the same array index.

Adding support to auto attach programs with following sections:

  fsession.multi/<pattern>
  fsession.multi.s/<pattern>
  fentry.multi/<pattern>
  fexit.multi/<pattern>
  fentry.multi.s/<pattern>
  fexit.multi.s/<pattern>

The provided <pattern> is used as 'pattern' argument in
bpf_program__attach_kprobe_multi_opts function.

The <pattern> allows to specify optional kernel module name with
following syntax:

  <module>:<function_pattern>

In order to attach tracing_multi link to a module functions:
- program must be loaded with 'module' btf fd
  (in attr::attach_btf_obj_fd)
- bpf_program__attach_tracing_multi must either have
  pattern with module spec or BTF ids from the module

Signed-off-by: Jiri Olsa <jolsa@kernel.org>
Link: https://lore.kernel.org/r/20260606123955.345967-21-jolsa@kernel.org
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
2026-06-07 10:03:02 -07:00
Jiri Olsa
616a93b473 libbpf: Add btf_type_is_traceable_func function
Adding btf_type_is_traceable_func function to perform same checks
as the kernel's btf_distill_func_proto function to prevent attachment
on some of the functions.

Exporting the function via libbpf_internal.h because it will be used
by benchmark test in following changes.

Signed-off-by: Jiri Olsa <jolsa@kernel.org>
Link: https://lore.kernel.org/r/20260606123955.345967-20-jolsa@kernel.org
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
2026-06-07 10:03:02 -07:00
Jiri Olsa
630e85a9f0 libbpf: Add bpf_link_create support for tracing_multi link
Adding bpf_link_create support for tracing_multi link with
new tracing_multi record in struct bpf_link_create_opts.

Signed-off-by: Jiri Olsa <jolsa@kernel.org>
Link: https://lore.kernel.org/r/20260606123955.345967-19-jolsa@kernel.org
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
2026-06-07 10:03:02 -07:00
Jiri Olsa
fe9c8cb2b5 libbpf: Add bpf_object_cleanup_btf function
Adding bpf_object_cleanup_btf function to cleanup btf objects.
It will be used in following changes.

Signed-off-by: Jiri Olsa <jolsa@kernel.org>
Link: https://lore.kernel.org/r/20260606123955.345967-18-jolsa@kernel.org
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
2026-06-07 10:03:02 -07:00
Jiri Olsa
ba042ed644 bpf: Add support for tracing_multi link session
Adding support to use session attachment with tracing_multi link.

Adding new BPF_TRACE_FSESSION_MULTI program attach type, that follows
the BPF_TRACE_FSESSION behaviour but on the tracing_multi link.

Such program is called on entry and exit of the attached function
and allows to pass cookie value from entry to exit execution.

Signed-off-by: Jiri Olsa <jolsa@kernel.org>
Link: https://lore.kernel.org/r/20260606123955.345967-16-jolsa@kernel.org
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
2026-06-07 10:03:01 -07:00
Jiri Olsa
c1d32dea5d bpf: Add support for tracing multi link
Adding new link to allow to attach program to multiple function
BTF IDs. The link is represented by struct bpf_tracing_multi_link.

To configure the link, new fields are added to bpf_attr::link_create
to pass array of BTF IDs;

  struct {
    __aligned_u64 ids;
    __u32         cnt;
  } tracing_multi;

Each BTF ID represents function (BTF_KIND_FUNC) that the link will
attach bpf program to.

We use previously added bpf_trampoline_multi_attach/detach functions
to attach/detach the link.

The linkinfo/fdinfo callbacks will be implemented in following changes.

Note this is supported only for archs (x86_64) with ftrace direct and
have single ops support.

  CONFIG_DYNAMIC_FTRACE_WITH_DIRECT_CALLS &&
  CONFIG_HAVE_SINGLE_FTRACE_DIRECT_OPS

Note using sort_r (instead of plain sort) in check_dup_ids, because we
will use the swap callback in following changes.

Signed-off-by: Jiri Olsa <jolsa@kernel.org>
Link: https://lore.kernel.org/r/20260606123955.345967-14-jolsa@kernel.org
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
2026-06-07 10:03:01 -07:00
Jiri Olsa
d14e6b4346 bpf: Add multi tracing attach types
Adding new program attach types multi tracing attachment:
  BPF_TRACE_FENTRY_MULTI
  BPF_TRACE_FEXIT_MULTI

and their base support in verifier code.

Programs with such attach type will use specific link attachment
interface coming in following changes.

This was suggested by Andrii some (long) time ago and turned out
to be easier than having special program flag for that.

Bpf programs with such types have 'bpf_multi_func' function set as
their attach_btf_id and keep module reference when it's specified
by attach_prog_fd.

They are also accepted as sleepable programs during verification,
and the real validation for specific BTF_IDs/functions will happen
during the multi link attachment in following changes.

Suggested-by: Andrii Nakryiko <andrii@kernel.org>
Signed-off-by: Jiri Olsa <jolsa@kernel.org>
Link: https://lore.kernel.org/r/20260606123955.345967-11-jolsa@kernel.org
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
2026-06-07 10:03:01 -07:00
Mykyta Yatsenko
6e46ff0abe libbpf: Support resizable hashtable
Add BPF_MAP_TYPE_RHASH to libbpf's map type name table and feature
probing so that libbpf-based tools can create and identify resizable
hash maps.

Signed-off-by: Mykyta Yatsenko <yatsenko@meta.com>
Reviewed-by: Emil Tsalapatis <emil@etsalapatis.com>
Link: https://lore.kernel.org/r/20260605-rhash-v7-8-5b8e05f8630d@meta.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
2026-06-05 08:00:08 -07:00
Daniel Borkmann
7fef1796ec libbpf: Guard add_data() against size overflow
add_data() computes size8 = roundup(size, 8) and then hands size8 to
realloc_data_buf() before doing memcpy(gen->data_cur, data, size) with
the original size. A wrapped size8 passes through the realloc_data_buf()
INT32_MAX check. Harden this against overflow, though not realistic to
happen in practice.

Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Link: https://lore.kernel.org/r/20260602133052.423725-3-daniel@iogearbox.net
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
2026-06-02 09:46:52 -07:00
Daniel Borkmann
60214435b3 libbpf: Skip max_entries override on signed loaders
bpf_gen__map_create() lets the host-supplied loader ctx override a
map's max_entries at runtime (map_desc[idx].max_entries, when non-zero).
This is how the light skeleton sizes maps to the target machine, but
it happens after emit_signature_match() and is covered by neither the
signed loader instructions nor the hashed blob.

For a signed loader this means an untrusted host can re-dimension the
program's maps, outside what the signature attests to. Gate the override
on gen_hash so signed loaders use the signer-provided max_entries baked
into the blob.

Fixes: ea923080c1 ("libbpf: Embed and verify the metadata hash in the loader")
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Link: https://lore.kernel.org/r/20260601150248.394863-6-daniel@iogearbox.net
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
2026-06-01 18:36:40 -07:00
Daniel Borkmann
61e0841523 libbpf: Skip initial_value override on signed loaders
bpf_gen__map_update_elem() emits code that, when the host-supplied
loader ctx provides a non-NULL map_desc[idx].initial_value, overwrites
the blob value with bytes read from the host (bpf_copy_from_user /
bpf_probe_read_kernel) before the BPF_MAP_UPDATE_ELEM that populates
the program's .data/.rodata/.bss maps.

This override runs after emit_signature_match() has validated map->sha[],
and initial_value is part of neither the signed loader instructions nor
the hashed data blob. For a signed loader this lets an untrusted host
substitute global-variable contents into a program whose code carries
a valid signature, thus weakening what the signature attests to.

The blob already contains the signer-provided value (added via add_data()
and covered by the embedded, signed hash), so simply skip emitting the
override for signed loaders (gen_hash). Runtime initialization stays
available for the unsigned light-skeleton path as before. The jump
offsets within the override block are internal to it, so guarding the
whole block leaves them unchanged.

Fixes: ea923080c1 ("libbpf: Embed and verify the metadata hash in the loader")
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Link: https://lore.kernel.org/r/20260601150248.394863-5-daniel@iogearbox.net
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
2026-06-01 18:36:40 -07:00
KP Singh
0fb6c9ed64 libbpf: Reject non-exclusive metadata maps in the signed loader
The loader verifies map->sha against the metadata hash in its
instructions. map->sha is calculated when BPF_OBJ_GET_INFO_BY_FD is
called on the frozen map.

While the map is frozen, the /signed loader/ must also ensure the map
is exclusive, as, without exclusivity (which a hostile host could just
omit when loading the loader), another BPF program with map access can
mutate the contents afterwards, so the check passes on stale data.

With the extra check as part of the signed loader, it now refuses to
move on with map->sha validation if the host set it up wrongly.

Fixes: fb2b0e2901 ("libbpf: Update light skeleton for signing")
Signed-off-by: KP Singh <kpsingh@kernel.org>
Co-developed-by: Daniel Borkmann <daniel@iogearbox.net>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Link: https://lore.kernel.org/r/20260601150248.394863-4-daniel@iogearbox.net
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
2026-06-01 18:36:40 -07:00
Daniel Borkmann
41300d032a libbpf: Skip endianness swap when loader generation failed
bpf_gen__prog_load() byte-swaps the program insns and the {func,line}_info
and CO-RE relo blobs in place for cross-endian targets. The blob offsets
come from add_data(), which returns 0 on failure: realloc_data_buf() either
frees and NULLs gen->data_start (realloc OOM) or returns early on an
already-latched gen->error, leaving a stale, possibly too-small buffer.

Neither bswap site checked for this. With gen->swapped_endian set and a
failed generation, "gen->data_start + off" becomes NULL + 0. Guard the
same way via !gen->error so they are skipped once generation has failed.

Fixes: 8ca3323dce ("libbpf: Support creating light skeleton of either endianness")
Reported-by: sashiko <sashiko@sashiko.dev>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Link: https://lore.kernel.org/r/20260529162829.315921-1-daniel@iogearbox.net
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
2026-05-31 17:48:27 -07:00
Daniel Borkmann
d2f7bd066e libbpf: Also reset {insn,data}_cur on realloc failure
realloc_insn_buf() as well as realloc_data_buf() free and NULL
gen->insn_start / gen->data_start on -ENOMEM but leave gen->insn_cur /
gen->data_cur pointing into the old, freed buffer. Just reset the
cursors to NULL alongside the base pointers so the freed state is
coherent.

Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Link: https://lore.kernel.org/r/20260529094119.307264-3-daniel@iogearbox.net
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
2026-05-31 17:47:48 -07:00
Daniel Borkmann
3c5e2f1a85 libbpf: Skip hash computation when loader generation failed
bpf_gen__finish() calls compute_sha_update_offsets() gated only on
the gen_hash option, without first consulting gen->error. On a failed
generation this is buggy: a failed realloc_data_buf() sets gen->data_start
to NULL (leaving gen->data_cur dangling), so compute_sha_update_offsets()
runs libbpf_sha256() over a NULL buffer with a bogus length; a failed
realloc_insn_buf() likewise sets gen->insn_start to NULL and the hash
immediates get patched through that NULL base.

The computed program is discarded in either case, since the following
"if (!gen->error)" block does not publish opts->insns once an error is
set. Thus, skip the hash pass when generation has already failed.

Fixes: ea923080c1 ("libbpf: Embed and verify the metadata hash in the loader")
Reported-by: sashiko <sashiko@sashiko.dev>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Link: https://lore.kernel.org/r/20260529094119.307264-2-daniel@iogearbox.net
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
2026-05-31 17:47:48 -07:00
Daniel Borkmann
e2c8826614 libbpf: Drop redundant self-loop in emit_check_err
When the cleanup-label jump offset does not fit in s16, emit_check_err()
sets gen->error = -ERANGE and then emits a BPF_JMP_IMM(BPF_JA, 0, 0, -1)
self-loop.

The latter emit() is dead: gen->error is assigned on the preceding line,
and emit() then bails out early in realloc_insn_buf() the moment gen->error
is set, so the jump is never written into the instruction stream.

gen->error alone already marks the generation as failed. This is a follow-up
to 7dd62566e0 ("libbpf: fix off-by-one in emit_signature_match jump offset")
which removed the jump in emit_signature_match() but not in other locations.

Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Link: https://lore.kernel.org/r/20260529094119.307264-1-daniel@iogearbox.net
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
2026-05-31 17:47:48 -07:00
Tiezhu Yang
a4a5d4ee06 libbpf: Add __NR_bpf definition for LoongArch
LoongArch uses the generic syscall table, where __NR_bpf is defined
as 280 in include/uapi/asm-generic/unistd.h.

To align with other architectures, add the __NR_bpf definition for
LoongArch to avoid a potential compilation failure: "error __NR_bpf
not defined. libbpf does not support your arch."

This is a follow up patch of:

  commit b0c47807d3 ("bpf: Add sparc support to tools and samples.")
  commit bad1926dd2 ("bpf, s390: fix build for libbpf and selftest suite")
  commit ca31ca8247 ("tools/bpf: fix perf build error with uClibc (seen on ARC)")
  commit e32cb12ff5 ("bpf, mips: Fix build errors about __NR_bpf undeclared")

Signed-off-by: Tiezhu Yang <yangtiezhu@loongson.cn>
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Link: https://lore.kernel.org/bpf/20260526063936.16769-1-yangtiezhu@loongson.cn
2026-05-28 14:38:15 -07:00
Carlos Llamas
b23705e6af libbpf: Fix UAF in strset__add_str()
strset_add_str_mem() might reallocate the strset data buffer in order to
accommodate the provided string 's'. However, if 's' points to a string
already present in the buffer, it becomes dangling after the realloc.
This leads to a use-after-free when attempting to memcpy() the string
into the new buffer.

One scenario that triggers this problematic path is when resolve_btfids
attempts to patch kfunc prototypes using existing BTF parameter names:

 | resolve_btfids: function bpf_list_push_back_impl already exists in BTF
 | Segmentation fault (core dumped)

Compiling resolve_btfids with fsanitize=address generates a detailed
report of the UAF:

 | =================================================================
 | ERROR: AddressSanitizer: heap-use-after-free on address 0x7f4c4a500bd4
 | ==1507892==ERROR: AddressSanitizer: heap-use-after-free on address 0x7f4c4a500bd4 at pc 0x55d25155a2a8 bp 0x7ffcef879060 sp 0x7ffcef878818
 | READ of size 5 at 0x7f4c4a500bd4 thread T0
 |     #0 0x55d25155a2a7 in memcpy (tools/bpf/resolve_btfids/resolve_btfids+0xcf2a7)
 |     #1 0x55d2515d708e in strset__add_str tools/lib/bpf/strset.c:162:2
 |     #2 0x55d2515c730b in btf__add_str tools/lib/bpf/btf.c:2109:8
 |     #3 0x55d2515c9020 in btf__add_func_param tools/lib/bpf/btf.c:3108:14
 |     #4 0x55d25159f0b5 in process_kfunc_with_implicit_args tools/bpf/resolve_btfids/main.c:1196:9
 |     #5 0x55d25159e004 in btf2btf tools/bpf/resolve_btfids/main.c:1229:9
 |     #6 0x55d25159cee7 in main tools/bpf/resolve_btfids/main.c:1535:6
 |     #7 0x7f4c78e29f76 in __libc_start_call_main csu/../sysdeps/nptl/libc_start_call_main.h:58:16
 |     #8 0x7f4c78e2a026 in __libc_start_main csu/../csu/libc-start.c:360:3
 |     #9 0x55d2514bb860 in _start (tools/bpf/resolve_btfids/resolve_btfids+0x30860)
 |
 | 0x7f4c4a500bd4 is located 13268 bytes inside of 2829000-byte region [0x7f4c4a4fd800,0x7f4c4a7b02c8)
 | freed by thread T0 here:
 |     #0 0x55d25155b700 in realloc (tools/bpf/resolve_btfids/resolve_btfids+0xd0700)
 |     #1 0x55d2515c426c in libbpf_reallocarray tools/lib/bpf/./libbpf_internal.h:220:9
 |     #2 0x55d2515c426c in libbpf_add_mem tools/lib/bpf/btf.c:224:13
 |
 | previously allocated by thread T0 here:
 |     #0 0x55d25155b2e3 in malloc (tools/bpf/resolve_btfids/resolve_btfids+0xd02e3)
 |     #1 0x55d2515d6e7d in strset__new tools/lib/bpf/strset.c:58:20

While resolve_btfids could be refactored to avoid this call path, let's
instead fix this issue at the source in strset__add_str() and avoid
similar scenarios.

Let's check if set->strs_data was reallocated and whether 's' points to
an internal string within the old strset buffer. In such case, 's' is
reconstructed to point to the new buffer.

While already here, also fix strset__find_str() which suffers from the
same problem by factoring out the common operations into a new helper
function strset_str_append().

Fixes: 90d76d3ece ("libbpf: Extract internal set-of-strings datastructure APIs")
Suggested-by: Andrii Nakryiko <andrii@kernel.org>
Suggested-by: Mykyta Yatsenko <yatsenko@meta.com>
Signed-off-by: Carlos Llamas <cmllamas@google.com>
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Link: https://lore.kernel.org/bpf/20260523162722.2718940-1-cmllamas@google.com
2026-05-28 14:25:55 -07:00
Michael Bommarito
fee9a38174 libbpf: Harden parse_vma_segs() path parsing
parse_vma_segs() in tools/lib/bpf/usdt.c parses /proc/<pid>/maps
with two widthless scansets, "%s" into mode[16] and "%[^\n]"
into line[4096]. A VMA name in maps is not limited to that local
buffer; a deeply nested backing path can produce a maps record long
enough to overflow the stack buffer.

Bound both scansets to the declared buffer sizes ("%15s" for mode[16]
and "%4095[^\n]" for line[4096]) and drain any residue past line[4094]
with "%*[^\n]" before the trailing "\n". Without the drain, the residue
of an over-long record would stay in the stream and break the next
"%zx-%zx" parse, so the loop would exit early and silently skip later
maps records.

Also stop using sscanf(..., "%s") to peel the /proc/<pid>/root prefix
from lib_path. Parse the pid and prefix length with "%n", check for the
following slash, and copy the remainder with libbpf_strlcpy(). That
removes a second unbounded stack write and preserves paths containing
spaces.

Fixes: 74cc6311ce ("libbpf: Add USDT notes parsing and resolution logic")
Signed-off-by: Michael Bommarito <michael.bommarito@gmail.com>
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Reviewed-by: Emil Tsalapatis <emil@etsalapatis.com>
Link: https://lore.kernel.org/bpf/20260522201353.1454653-1-michael.bommarito@gmail.com
2026-05-28 14:15:48 -07:00
Tomas Glozar
da62fc3458 tools subcmd: allow parsing distinct --opt and --no-opt
libsubcmd automatically generates for every option --opt an equivalent
negated option, --no-opt, to unset the option. Vice versa, for every
option declared as --no-opt, a shorthand --opt is declared for
convenience.

Add a flag, PARSE_OPT_NOAUTONEG, to disable this behavior. This new flag
behaves similarly to the already existing PARSE_OPT_NONEG, only it does
not reject the --no-opt variant, but leaves it undefined. That is useful
when there is a conflicting distinct --no-opt option in the syntax of
the tool.

PARSE_OPT_NOAUTONEG is enabled per-option, allowing to unset other
options that do not have this conflict.

Link: https://lore.kernel.org/r/20260528103254.2990068-4-tglozar@redhat.com
Signed-off-by: Tomas Glozar <tglozar@redhat.com>
2026-05-28 13:02:48 +02:00
Tomas Glozar
534d9a93db tools subcmd: support optarg as separate argument
In addition to "-ovalue" and "--opt=value" syntax, allow also "-o value"
and "--opt value" for options with optional argument when the newly
added PARSE_OPT_OPTARG_ALLOW_NEXT flag is set.

This behavior is turned off by default since it does not make sense for
tools using non-option command line arguments. Consider the ambiguity
of "cmd -d x", where "-d x" can mean either "-d with argument of x" or
"-d without argument, followed by non-option argument x". This is not an
issue in the case that the tool takes no non-option arguments.

To implement this, a new local variable, force_defval, is created in
get_value(), along with a comment explaining the logic.

Link: https://lore.kernel.org/r/20260528103254.2990068-3-tglozar@redhat.com
Signed-off-by: Tomas Glozar <tglozar@redhat.com>
2026-05-28 13:02:47 +02:00
Alexei Starovoitov
eb19eead36 Merge git://git.kernel.org/pub/scm/linux/kernel/git/bpf/bpf 7.1-rc5
Cross-merge BPF and other fixes after downstream PR.

Signed-off-by: Alexei Starovoitov <ast@kernel.org>
2026-05-25 06:33:30 -07:00
KP Singh
7dd62566e0 libbpf: fix off-by-one in emit_signature_match jump offset
The offset for the cleanup-label jump is computed before the MOV R7
instruction is emitted, but the JMP lands after it. Account for the
extra insn in the offset calculation (-2 instead of -1). Drop the
redundant self-loop in the else branch; gen->error = -ERANGE already
marks the generation as failed.

Fixes: fb2b0e2901 ("libbpf: Update light skeleton for signing")
Signed-off-by: KP Singh <kpsingh@kernel.org>
Link: https://lore.kernel.org/r/20260522215337.662271-2-kpsingh@kernel.org
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
2026-05-23 07:49:22 -07:00
Leon Hwang
b4844cb6d1 libbpf: Add OPTS_VALID() for log_opts in bpf_map_create
There should be an OPTS_VALID() check for log_opts before extracting its
fields.

If no such OPTS_VALID() check and an application compiled against a future
libbpf header passes a log_opts with new, non-zero fields to libbpf.so,
those fields will be ignored silently.

Fixes: 702259006f ("libbpf: Add syscall common attributes support for map_create")
Signed-off-by: Leon Hwang <leon.hwang@linux.dev>
Link: https://lore.kernel.org/r/20260518145446.6794-4-leon.hwang@linux.dev
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
2026-05-18 18:51:32 -07:00
Shuicheng Lin
46d9c16115 scripts/kernel-doc: Detect mismatched inline member documentation tags
Add validation in check_sections() to verify that inline member
documentation tags (/** @member: description */) match actual struct/union
member names. Previously, kernel-doc only validated section headers against
the parameter list, but inline doc tags stored in parameterdescs were never
cross-checked, allowing stale or mistyped member names to go undetected.

The new check iterates over parameterdescs keys and warns about any that
don't appear in the parameter list, catching issues like renamed struct
members where the documentation tag was not updated to match.

This catches real issues such as:
  - xe_bo_types.h: @atomic_access (missing struct prefix, should be
    @attr.atomic_access)
  - xe_device_types.h: @usm.asid (member is actually asid_to_vm)

While at it, fix two long-standing issues with named variadic parameters
(macros like ``#define foo(fmt, args...)``) that the new check exposed:

  1. A description provided via the ``@args...:`` doc form was stored
     in parameterdescs under the unstripped key ``args...``, while
     push_parameter() stripped the trailing ``...`` and only added
     ``args`` to parameterlist.  As a result the user-supplied
     description was orphaned, parameterdescs[``args``] was auto-
     populated with the generic "variable arguments" text, and the
     user's actual description was silently discarded by the output
     stage.  Migrate the description from the unstripped to the
     stripped key inside push_parameter() so the user's text reaches
     the output and the new check does not flag the orphaned key.

  2. push_parameter() always auto-populated parameterdescs[param] with
     "variable arguments" for variadic parameters, which bypassed the
     existing "parameter not described" warning at line 549.  As a
     consequence, a named variadic with no matching ``@<name>:`` doc
     tag (or a mistyped one such as ``@args:`` for a parameter named
     ``arg``) went undetected.  Emit the standard "not described"
     warning for named variadics before applying the auto-fill, so
     missing or mistyped variadic docs are reported just like missing
     docs for any other parameter.  The bare ``@...:`` form is
     unaffected because it has no natural name for the user to
     document.

This second hunk surfaces one real pre-existing documentation gap in
include/linux/hashtable.h: hash_for_each_possible_rcu()'s ``cond...``
parameter has no matching ``@cond:`` doc entry.  No false positives were
observed across include/linux, kernel/, or drivers/gpu/drm.

v2: Skip variadic parameters whose documented key ends with ``...`` and
    whose stripped name is in parameterlist, to avoid false-positive
    "Excess function parameter 'args...'" warnings on macros like
    ``#define foo(fmt, args...)`` documented with ``@args...:``.

v3: The v2 special case in check_sections() only suppressed the warning
    while still letting the user's description be silently dropped from
    the generated output.  Replace it with a fix in push_parameter() that
    migrates the description from ``args...`` to ``args`` when the name
    is stripped, so the user's text is preserved end-to-end and the
    new excess-parameter check naturally finds nothing to flag.

v4: Also emit the standard "parameter not described" warning for named
    variadics that have no matching ``@<name>:`` doc tag.  Previously
    push_parameter()'s unconditional auto-fill bypassed that warning,
    so a missing or mistyped variadic doc went undetected. (Randy)

Assisted-by: Claude:claude-opus-4.6
Signed-off-by: Shuicheng Lin <shuicheng.lin@intel.com>
Tested-by: Randy Dunlap <rdunlap@infradead.org>
Acked-by: Randy Dunlap <rdunlap@infradead.org>
Signed-off-by: Jonathan Corbet <corbet@lwn.net>
Message-ID: <20260507023232.4108680-1-shuicheng.lin@intel.com>
2026-05-15 08:34:13 -06:00
Randy Dunlap
026d7010f1 kdoc: xforms: move context attrs to function_xforms list
The context analysis macros are function attributes that should be
in the function_xforms list. Somewhere along the way they were
inserted into the struct_xforms list instead. This causes docs build
warnings to continue to be emitted for context macros.

Move the context analysis macros to the function_xforms list where
they should be to eliminate these warnings.

Documentation/core-api/kref:328: ../include/linux/kref.h:72: WARNING: Invalid C declaration: Expected end of definition. [error at 96]
  int kref_put_mutex (struct kref *kref, void (*release)(struct kref *kref), struct mutex *mutex) __cond_acquires(true# mutex)
Documentation/core-api/kref:328: ../include/linux/kref.h:94: WARNING: Invalid C declaration: Expected end of definition. [error at 92]
  int kref_put_lock (struct kref *kref, void (*release)(struct kref *kref), spinlock_t *lock) __cond_acquires(true# lock)

Signed-off-by: Randy Dunlap <rdunlap@infradead.org>
Signed-off-by: Jonathan Corbet <corbet@lwn.net>
Message-ID: <20260505221548.163751-1-rdunlap@infradead.org>
2026-05-15 08:15:54 -06:00
Tudor Ambarus
8bf5a177c3 docs: kernel-doc: python: strip __counted_by_ptr macro
The `__counted_by_ptr` macro was recently introduced [1] to extend
bounds checking semantics to standard dynamically allocated pointers.

However, the new Python implementation of kernel-doc does not currently
recognize it as a compiler attribute. When kernel-doc encounters a
struct member annotated with this macro, it fails to parse the variable
name correctly, resulting in false-positive warnings like:

  Warning: ... struct member '__counted_by_ptr(cmdcnt' not described

Add `__counted_by_ptr` to the `struct_xforms` regex list so it gets
safely stripped out during the parsing phase, mirroring the existing
behavior for `__counted_by`. Update the corresponding unit tests.

Link: https://git.kernel.org/torvalds/c/150a04d817d8 [1]
Signed-off-by: Tudor Ambarus <tudor.ambarus@linaro.org>
Reviewed-by: Mauro Carvalho Chehab <mchehab+huawei@kernel.org>
Reviewed-by: Kees Cook <kees@kernel.org>
Acked-by: Randy Dunlap <rdunlap@infradead.org>
Tested-by: Randy Dunlap <rdunlap@infradead.org>
Signed-off-by: Jonathan Corbet <corbet@lwn.net>
Message-ID: <20260506-kdoc-__counted_by_ptr-v1-1-70763486871f@linaro.org>
2026-05-15 08:11:36 -06:00
Kees Cook
74a9bb761a libbpf: Use strscpy() in kernel code for skel_map_create()
Linux has deprecated[1] strncpy(), and the use in skel_map_create()
is best replaced with strscpy(). Since we still need to build this
file in userspace, leave the strncpy() in place in that case. This
is the last use of strncpy() in the kernel.

Link: https://github.com/KSPP/linux/issues/90 [1]
Signed-off-by: Kees Cook <kees@kernel.org>
Link: https://lore.kernel.org/r/20260513050806.do.620-kees@kernel.org
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
2026-05-13 10:52:32 -07:00
Leon Hwang
702259006f libbpf: Add syscall common attributes support for map_create
With the previous commit adding common attribute support for
BPF_MAP_CREATE, users can now retrieve detailed error messages when map
creation fails via the log_buf field.

Introduce struct bpf_log_opts with the following fields:
log_buf, log_size, log_level, and log_true_size.

Extend bpf_map_create_opts with a new field log_opts, allowing users to
capture and inspect log messages on map creation failures.

Acked-by: Andrii Nakryiko <andrii@kernel.org>
Signed-off-by: Leon Hwang <leon.hwang@linux.dev>
Link: https://lore.kernel.org/r/20260512153157.28382-8-leon.hwang@linux.dev
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
2026-05-12 12:44:46 -07:00
Leon Hwang
b1bff40809 libbpf: Add support for extended BPF syscall
To support the extended BPF syscall introduced in the previous commit,
introduce the following internal APIs:

* 'sys_bpf_ext()'
* 'sys_bpf_ext_fd()'
  They wrap the raw 'syscall()' interface to support passing extended
  attributes.
* 'probe_sys_bpf_ext()'
  Check whether current kernel supports the BPF syscall common attributes.

Acked-by: Andrii Nakryiko <andrii@kernel.org>
Signed-off-by: Leon Hwang <leon.hwang@linux.dev>
Link: https://lore.kernel.org/r/20260512153157.28382-3-leon.hwang@linux.dev
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
2026-05-12 12:44:39 -07:00
Alexei Starovoitov
7e033543a2 Merge git://git.kernel.org/pub/scm/linux/kernel/git/bpf/bpf 7.1-rc3
Cross-merge BPF and other fixes after downstream PR.

Signed-off-by: Alexei Starovoitov <ast@kernel.org>
2026-05-10 13:24:49 -07:00
Randy Dunlap
713e899a68 docs: xforms_lists: allow __maybe_unused in func parameters
Bart has a patch (not yet merged) that causes kernel-doc warnings:

WARNING: ./include/linux/highmem.h:235 function parameter '__maybe_unused' not described in 'clear_user_pages'
Documentation/mm/highmem:211: ./include/linux/highmem.h:222: WARNING: Error in declarator or parameters

Handle this by adding "__maybe_unused" to the list of known function
parameter modifiers.

Reported-by: kernel test robot <lkp@intel.com>
Closes: https://lore.kernel.org/oe-kbuild-all/202604120025.jtlnpWff-lkp@intel.com/
Signed-off-by: Randy Dunlap <rdunlap@infradead.org>
Cc: Bart Van Assche <bvanassche@acm.org>
Reviewed-by: Bart Van Assche <bvanassche@acm.org>
Signed-off-by: Jonathan Corbet <corbet@lwn.net>
Message-ID: <20260411233526.3909303-1-rdunlap@infradead.org>
2026-04-27 04:07:06 -06:00
Antoine Tenart
0831b110eb libbpf: Fix deduplication of typedef with base definitions
When deduplicating definitions for a module, typedef defined in the base
are not removed. This is because the hash used for base types differs
from the one used in the deduplication logic in btf_dedup_struct_type.

This was introduced by the referenced commit when moving the typedef
deduplication logic handling from btf_dedup_ref_type to
btf_dedup_struct_type, as this also changed the hash logic
(btf_hash_common to btf_hash_typedef).

This also impacts other types referencing those typedef (e.g. const). In
my test, the BTF section size of the openvswitch module went from 31KB
to 45KB.

Fixes: 3781413465 ("libbpf: Fix BTF dedup to support recursive typedef definitions").
Signed-off-by: Antoine Tenart <atenart@kernel.org>
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Tested-by: Alan Maguire <alan.maguire@oracle.com>
Reviewed-by: Alan Maguire <alan.maguire@oracle.com>
Link: https://lore.kernel.org/bpf/20260417083319.32716-1-atenart@kernel.org
2026-04-22 14:18:41 -07:00
Mykyta Yatsenko
0cd420a6f4 libbpf: Add section handlers for sleepable tracepoints
Add SEC_DEF entries for sleepable tracepoint variants:
  - "tp_btf.s+"     for sleepable BTF-based raw tracepoints
  - "raw_tp.s+"     for sleepable raw tracepoints
  - "raw_tracepoint.s+" (alias)
  - "tp.s+"         for sleepable classic tracepoints
  - "tracepoint.s+" (alias)

Extract sec_name_match_prefix() to share the prefix matching logic
between attach_tp() and attach_raw_tp(), eliminating duplicated
loops and hardcoded strcmp() checks for bare section names.

Signed-off-by: Mykyta Yatsenko <yatsenko@meta.com>
Acked-by: Kumar Kartikeya Dwivedi <memxor@gmail.com>
Link: https://lore.kernel.org/bpf/20260422-sleepable_tracepoints-v13-5-99005dff21ef@meta.com
Signed-off-by: Kumar Kartikeya Dwivedi <memxor@gmail.com>
2026-04-22 22:44:30 +02:00
Linus Torvalds
e2683c8868 Merge tag 'libcrypto-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/ebiggers/linux
Pull more crypto library updates from Eric Biggers:
 "Crypto library fix and documentation update:

   - Fix an integer underflow in the mpi library

   - Improve the crypto library documentation"

* tag 'libcrypto-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/ebiggers/linux:
  lib/crypto: docs: Add rst documentation to Documentation/crypto/
  docs: kdoc: Expand 'at_least' when creating parameter list
  lib/crypto: mpi: Fix integer underflow in mpi_read_raw_from_sgl()
2026-04-21 11:46:22 -07:00
Alan Maguire
cacd6729c0 libbpf: Adjust btf_vlen() to return a __u32
Now that vlen is 24 bits, btf_vlen() must return a __u32.
Adjust use cases in libbpf accordingly.  Also add error
handling to avoid vlen overflow in btf_type_inc_vlen().

Signed-off-by: Alan Maguire <alan.maguire@oracle.com>
Acked-by: Mykyta Yatsenko <yatsenko@meta.com>
Link: https://lore.kernel.org/r/20260417143023.1551481-3-alan.maguire@oracle.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
2026-04-20 17:52:48 -07:00
Aaron Tomlin
ad35d80186 libbpf: Report error when a negative kprobe offset is specified
In attach_kprobe(), the parsing logic uses sscanf() to extract the
target function name and offset from the section definition. Currently,
if a user specifies a negative offset (e.g., SEC("kprobe/func+-100")),
the input is not explicitly caught and reported as an error.

This commit updates the logic to explicitly notify the user when a
negative integer is provided. To facilitate this check, the offset
variable is changed from unsigned long to long so that sscanf()
can accurately capture a negative input for evaluation.

If a negative offset is detected, the loader will now print an
informative warning stating that the offset must be non-negative,
and return -EINVAL.

Additionally, free(func) is called in this new error path to prevent
a memory leak, as the function name string is dynamically allocated
by sscanf().

Fixes: e3f9bc35ea ("libbpf: Allow decimal offset for kprobes")
Signed-off-by: Aaron Tomlin <atomlin@atomlin.com>
Acked-by: Mykyta Yatsenko <yatsenko@meta.com>
Link: https://lore.kernel.org/bpf/20260419030944.1423642-1-atomlin@atomlin.com
Signed-off-by: Kumar Kartikeya Dwivedi <memxor@gmail.com>
2026-04-19 13:52:34 +02:00
Eric Biggers
6fa6b5cb60 docs: kdoc: Expand 'at_least' when creating parameter list
sphinx doesn't know that the kernel headers do:

    #define at_least static

Do this replacement before declarations are passed to it.

This prevents errors like the following from appearing once the
lib/crypto/ kernel-doc is wired up to the sphinx build:

   linux/Documentation/crypto/libcrypto:128: ./include/crypto/sha2.h:773: WARNING: Error in declarator or parameters
Error in declarator or parameters
Invalid C declaration: Expected ']' in end of array operator. [error at 59]
  void sha512_final (struct sha512_ctx *ctx, u8 out[at_least SHA512_DIGEST_SIZE])

Acked-by: Jonathan Corbet <corbet@lwn.net>
Reviewed-by: Ard Biesheuvel <ardb@kernel.org>
Acked-by: Randy Dunlap <rdunlap@infradead.org>
Tested-by: Randy Dunlap <rdunlap@infradead.org>
Link: https://lore.kernel.org/r/20260418192138.15556-2-ebiggers@kernel.org
Signed-off-by: Eric Biggers <ebiggers@kernel.org>
2026-04-18 17:32:01 -07:00
Linus Torvalds
df8f6181ab Merge tag 'perf-tools-for-v7.1-2026-04-17' of git://git.kernel.org/pub/scm/linux/kernel/git/perf/perf-tools
Pull perf tools updates from Namhyung Kim:
 "perf report:

   - Add 'comm_nodigit' sort key to combine similar threads that only
     have different numbers in the comm. In the following example, the
     'comm_nodigit' will have samples from all threads starting with
     "bpfrb/" into an entry "bpfrb/<N>".

        $ perf report -s comm_nodigit,comm -H
        ...
        #
        #    Overhead  CommandNoDigit / Command
        # ...........  ........................
        #
            20.30%     swapper
               20.30%     swapper
            13.37%     chrome
               13.37%     chrome
            10.07%     bpfrb/<N>
                7.47%     bpfrb/0
                0.70%     bpfrb/1
                0.47%     bpfrb/3
                0.46%     bpfrb/2
                0.25%     bpfrb/4
                0.23%     bpfrb/5
                0.20%     bpfrb/6
                0.14%     bpfrb/10
                0.07%     bpfrb/7

   - Support flat layout for symfs. The --symfs option is to specify the
     location of debugging symbol files. The default 'hierarchy' layout
     would search the symbol file using the same path of the original
     file under the symfs root. The new 'flat' layout would search only
     in the root directory.

   - Update 'simd' sort key for ARM SIMD flags to cover ASE/SME and more
     predicate flags.

  perf stat:

   - Add --pmu-filter option to select specific PMUs. This would be
     useful when you measure metrics from multiple instance of uncore
     PMUs with similar names.

        # perf stat -M cpa_p0_avg_bw
         Performance counter stats for 'system wide':

            19,417,779,115      hisi_sicl0_cpa0/cpa_cycles/      #     0.00 cpa_p0_avg_bw
                         0      hisi_sicl0_cpa0/cpa_p0_wr_dat/
                         0      hisi_sicl0_cpa0/cpa_p0_rd_dat_64b/
                         0      hisi_sicl0_cpa0/cpa_p0_rd_dat_32b/
            19,417,751,103      hisi_sicl10_cpa0/cpa_cycles/     #     0.00 cpa_p0_avg_bw
                         0      hisi_sicl10_cpa0/cpa_p0_wr_dat/
                         0      hisi_sicl10_cpa0/cpa_p0_rd_dat_64b/
                         0      hisi_sicl10_cpa0/cpa_p0_rd_dat_32b/
            19,417,730,679      hisi_sicl2_cpa0/cpa_cycles/      #     0.31 cpa_p0_avg_bw
                75,635,749      hisi_sicl2_cpa0/cpa_p0_wr_dat/
                18,520,640      hisi_sicl2_cpa0/cpa_p0_rd_dat_64b/
                         0      hisi_sicl2_cpa0/cpa_p0_rd_dat_32b/
            19,417,674,227      hisi_sicl8_cpa0/cpa_cycles/      #     0.00 cpa_p0_avg_bw
                         0      hisi_sicl8_cpa0/cpa_p0_wr_dat/
                         0      hisi_sicl8_cpa0/cpa_p0_rd_dat_64b/
                         0      hisi_sicl8_cpa0/cpa_p0_rd_dat_32b/

              19.417734480 seconds time elapsed

     With --pmu-filter, users can select only hisi_sicl2_cpa0 PMU.

        # perf stat --pmu-filter hisi_sicl2_cpa0 -M cpa_p0_avg_bw
         Performance counter stats for 'system wide':

             6,234,093,559      cpa_cycles                       #     0.60 cpa_p0_avg_bw
                50,548,465      cpa_p0_wr_dat
                 7,552,182      cpa_p0_rd_dat_64b
                         0      cpa_p0_rd_dat_32b

               6.234139320 seconds time elapsed

  Data type profiling:

   - Quality improvements by tracking register state more precisely

   - Ensure array members to get the type

   - Handle more cases for global variables

  Vendor event/metric updates:

   - Update various Intel events and metrics

   - Add NVIDIA Tegra 410 Olympus events

  Internal changes:

   - Verify perf.data header for maliciously crafted files

   - Update perf test to cover more usages and make them robust

   - Move a couple of copied kernel headers not to annoy objtool build

   - Fix a bug in map sorting in name order

   - Remove some unused codes

  Misc:

   - Fix module symbol resolution with non-zero text address

   - Add -t/--threads option to `perf bench mem mmap`

   - Track duration of exit*() syscall by `perf trace -s`

   - Add core.addr2line-timeout and core.addr2line-disable-warn config
     items"

* tag 'perf-tools-for-v7.1-2026-04-17' of git://git.kernel.org/pub/scm/linux/kernel/git/perf/perf-tools: (131 commits)
  perf loongarch: Fix build failure with CONFIG_LIBDW_DWARF_UNWIND
  perf annotate: Use jump__delete when freeing LoongArch jumps
  perf test: Fixes for check branch stack sampling
  perf test: Fix inet_pton probe failure and unroll call graph
  perf build: fix "argument list too long" in second location
  perf header: Add sanity checks to HEADER_BPF_BTF processing
  perf header: Sanity check HEADER_BPF_PROG_INFO
  perf header: Sanity check HEADER_PMU_CAPS
  perf header: Sanity check HEADER_HYBRID_TOPOLOGY
  perf header: Sanity check HEADER_CACHE
  perf header: Sanity check HEADER_GROUP_DESC
  perf header: Sanity check HEADER_PMU_MAPPINGS
  perf header: Sanity check HEADER_MEM_TOPOLOGY
  perf header: Sanity check HEADER_NUMA_TOPOLOGY
  perf header: Sanity check HEADER_CPU_TOPOLOGY
  perf header: Sanity check HEADER_NRCPUS and HEADER_CPU_DOMAIN_INFO
  perf header: Bump up the max number of command line args allowed
  perf header: Validate nr_domains when reading HEADER_CPU_DOMAIN_INFO
  perf sample: Fix documentation typo
  perf arm_spe: Improve SIMD flags setting
  ...
2026-04-18 09:24:56 -07:00
Linus Torvalds
eb0d6d97c2 Merge tag 'bpf-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/bpf/bpf
Pull bpf fixes from Alexei Starovoitov:
 "Most of the diff stat comes from Xu Kuohai's fix to emit ENDBR/BTI,
  since all JITs had to be touched to move constant blinding out and
  pass bpf_verifier_env in.

   - Fix use-after-free in arena_vm_close on fork (Alexei Starovoitov)

   - Dissociate struct_ops program with map if map_update fails (Amery
     Hung)

   - Fix out-of-range and off-by-one bugs in arm64 JIT (Daniel Borkmann)

   - Fix precedence bug in convert_bpf_ld_abs alignment check (Daniel
     Borkmann)

   - Fix arg tracking for imprecise/multi-offset in BPF_ST/STX insns
     (Eduard Zingerman)

   - Copy token from main to subprogs to fix missing kallsyms (Eduard
     Zingerman)

   - Prevent double close and leak of btf objects in libbpf (Jiri Olsa)

   - Fix af_unix null-ptr-deref in sockmap (Michal Luczaj)

   - Fix NULL deref in map_kptr_match_type for scalar regs (Mykyta
     Yatsenko)

   - Avoid unnecessary IPIs. Remove redundant bpf_flush_icache() in
     arm64 and riscv JITs (Puranjay Mohan)

   - Fix out of bounds access. Validate node_id in arena_alloc_pages()
     (Puranjay Mohan)

   - Reject BPF-to-BPF calls and callbacks in arm32 JIT (Puranjay Mohan)

   - Refactor all JITs to pass bpf_verifier_env to emit ENDBR/BTI for
     indirect jump targets on x86-64, arm64 JITs (Xu Kuohai)

   - Allow UTF-8 literals in bpf_bprintf_prepare() (Yihan Ding)"

* tag 'bpf-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/bpf/bpf: (32 commits)
  bpf, arm32: Reject BPF-to-BPF calls and callbacks in the JIT
  bpf: Dissociate struct_ops program with map if map_update fails
  bpf: Validate node_id in arena_alloc_pages()
  libbpf: Prevent double close and leak of btf objects
  selftests/bpf: cover UTF-8 trace_printk output
  bpf: allow UTF-8 literals in bpf_bprintf_prepare()
  selftests/bpf: Reject scalar store into kptr slot
  bpf: Fix NULL deref in map_kptr_match_type for scalar regs
  bpf: Fix precedence bug in convert_bpf_ld_abs alignment check
  bpf, arm64: Emit BTI for indirect jump target
  bpf, x86: Emit ENDBR for indirect jump targets
  bpf: Add helper to detect indirect jump targets
  bpf: Pass bpf_verifier_env to JIT
  bpf: Move constants blinding out of arch-specific JITs
  bpf, sockmap: Take state lock for af_unix iter
  bpf, sockmap: Fix af_unix null-ptr-deref in proto update
  selftests/bpf: Extend bpf_iter_unix to attempt deadlocking
  bpf, sockmap: Fix af_unix iter deadlock
  bpf, sockmap: Annotate af_unix sock:: Sk_state data-races
  selftests/bpf: verify kallsyms entries for token-loaded subprograms
  ...
2026-04-17 15:58:22 -07:00
Jiri Olsa
380044c40b libbpf: Prevent double close and leak of btf objects
Sashiko found possible double close of btf object fd [1],
which happens when strdup in load_module_btfs fails at which
point the obj->btf_module_cnt is already incremented.

The error path close btf fd and so does later cleanup code in
bpf_object_post_load_cleanup function.

Also libbpf_ensure_mem failure leaves btf object not assigned
and it's leaked.

Replacing the err_out label with break to make the error path
less confusing as suggested by Alan.

Incrementing obj->btf_module_cnt only if there's no failure
and releasing btf object in error path.

Fixes: 91abb4a6d7 ("libbpf: Support attachment of BPF tracing programs to kernel modules")
[1] https://sashiko.dev/#/patchset/20260324081846.2334094-1-jolsa%40kernel.org
Signed-off-by: Jiri Olsa <jolsa@kernel.org>
Link: https://lore.kernel.org/r/20260416100034.1610852-1-jolsa@kernel.org
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
2026-04-16 16:00:10 -07:00
Linus Torvalds
334fbe734e Merge tag 'mm-stable-2026-04-13-21-45' of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm
Pull MM updates from Andrew Morton:

 - "maple_tree: Replace big node with maple copy" (Liam Howlett)

   Mainly prepararatory work for ongoing development but it does reduce
   stack usage and is an improvement.

 - "mm, swap: swap table phase III: remove swap_map" (Kairui Song)

   Offers memory savings by removing the static swap_map. It also yields
   some CPU savings and implements several cleanups.

 - "mm: memfd_luo: preserve file seals" (Pratyush Yadav)

   File seal preservation to LUO's memfd code

 - "mm: zswap: add per-memcg stat for incompressible pages" (Jiayuan
   Chen)

   Additional userspace stats reportng to zswap

 - "arch, mm: consolidate empty_zero_page" (Mike Rapoport)

   Some cleanups for our handling of ZERO_PAGE() and zero_pfn

 - "mm/kmemleak: Improve scan_should_stop() implementation" (Zhongqiu
   Han)

   A robustness improvement and some cleanups in the kmemleak code

 - "Improve khugepaged scan logic" (Vernon Yang)

   Improve khugepaged scan logic and reduce CPU consumption by
   prioritizing scanning tasks that access memory frequently

 - "Make KHO Stateless" (Jason Miu)

   Simplify Kexec Handover by transitioning KHO from an xarray-based
   metadata tracking system with serialization to a radix tree data
   structure that can be passed directly to the next kernel

 - "mm: vmscan: add PID and cgroup ID to vmscan tracepoints" (Thomas
   Ballasi and Steven Rostedt)

   Enhance vmscan's tracepointing

 - "mm: arch/shstk: Common shadow stack mapping helper and
   VM_NOHUGEPAGE" (Catalin Marinas)

   Cleanup for the shadow stack code: remove per-arch code in favour of
   a generic implementation

 - "Fix KASAN support for KHO restored vmalloc regions" (Pasha Tatashin)

   Fix a WARN() which can be emitted the KHO restores a vmalloc area

 - "mm: Remove stray references to pagevec" (Tal Zussman)

   Several cleanups, mainly udpating references to "struct pagevec",
   which became folio_batch three years ago

 - "mm: Eliminate fake head pages from vmemmap optimization" (Kiryl
   Shutsemau)

   Simplify the HugeTLB vmemmap optimization (HVO) by changing how tail
   pages encode their relationship to the head page

 - "mm/damon/core: improve DAMOS quota efficiency for core layer
   filters" (SeongJae Park)

   Improve two problematic behaviors of DAMOS that makes it less
   efficient when core layer filters are used

 - "mm/damon: strictly respect min_nr_regions" (SeongJae Park)

   Improve DAMON usability by extending the treatment of the
   min_nr_regions user-settable parameter

 - "mm/page_alloc: pcp locking cleanup" (Vlastimil Babka)

   The proper fix for a previously hotfixed SMP=n issue. Code
   simplifications and cleanups ensued

 - "mm: cleanups around unmapping / zapping" (David Hildenbrand)

   A bunch of cleanups around unmapping and zapping. Mostly
   simplifications, code movements, documentation and renaming of
   zapping functions

 - "support batched checking of the young flag for MGLRU" (Baolin Wang)

   Batched checking of the young flag for MGLRU. It's part cleanups; one
   benchmark shows large performance benefits for arm64

 - "memcg: obj stock and slab stat caching cleanups" (Johannes Weiner)

   memcg cleanup and robustness improvements

 - "Allow order zero pages in page reporting" (Yuvraj Sakshith)

   Enhance free page reporting - it is presently and undesirably order-0
   pages when reporting free memory.

 - "mm: vma flag tweaks" (Lorenzo Stoakes)

   Cleanup work following from the recent conversion of the VMA flags to
   a bitmap

 - "mm/damon: add optional debugging-purpose sanity checks" (SeongJae
   Park)

   Add some more developer-facing debug checks into DAMON core

 - "mm/damon: test and document power-of-2 min_region_sz requirement"
   (SeongJae Park)

   An additional DAMON kunit test and makes some adjustments to the
   addr_unit parameter handling

 - "mm/damon/core: make passed_sample_intervals comparisons
   overflow-safe" (SeongJae Park)

   Fix a hard-to-hit time overflow issue in DAMON core

 - "mm/damon: improve/fixup/update ratio calculation, test and
   documentation" (SeongJae Park)

   A batch of misc/minor improvements and fixups for DAMON

 - "mm: move vma_(kernel|mmu)_pagesize() out of hugetlb.c" (David
   Hildenbrand)

   Fix a possible issue with dax-device when CONFIG_HUGETLB=n. Some code
   movement was required.

 - "zram: recompression cleanups and tweaks" (Sergey Senozhatsky)

   A somewhat random mix of fixups, recompression cleanups and
   improvements in the zram code

 - "mm/damon: support multiple goal-based quota tuning algorithms"
   (SeongJae Park)

   Extend DAMOS quotas goal auto-tuning to support multiple tuning
   algorithms that users can select

 - "mm: thp: reduce unnecessary start_stop_khugepaged()" (Breno Leitao)

   Fix the khugpaged sysfs handling so we no longer spam the logs with
   reams of junk when starting/stopping khugepaged

 - "mm: improve map count checks" (Lorenzo Stoakes)

   Provide some cleanups and slight fixes in the mremap, mmap and vma
   code

 - "mm/damon: support addr_unit on default monitoring targets for
   modules" (SeongJae Park)

   Extend the use of DAMON core's addr_unit tunable

 - "mm: khugepaged cleanups and mTHP prerequisites" (Nico Pache)

   Cleanups to khugepaged and is a base for Nico's planned khugepaged
   mTHP support

 - "mm: memory hot(un)plug and SPARSEMEM cleanups" (David Hildenbrand)

   Code movement and cleanups in the memhotplug and sparsemem code

 - "mm: remove CONFIG_ARCH_ENABLE_MEMORY_HOTREMOVE and cleanup
   CONFIG_MIGRATION" (David Hildenbrand)

   Rationalize some memhotplug Kconfig support

 - "change young flag check functions to return bool" (Baolin Wang)

   Cleanups to change all young flag check functions to return bool

 - "mm/damon/sysfs: fix memory leak and NULL dereference issues" (Josh
   Law and SeongJae Park)

   Fix a few potential DAMON bugs

 - "mm/vma: convert vm_flags_t to vma_flags_t in vma code" (Lorenzo
   Stoakes)

   Convert a lot of the existing use of the legacy vm_flags_t data type
   to the new vma_flags_t type which replaces it. Mainly in the vma
   code.

 - "mm: expand mmap_prepare functionality and usage" (Lorenzo Stoakes)

   Expand the mmap_prepare functionality, which is intended to replace
   the deprecated f_op->mmap hook which has been the source of bugs and
   security issues for some time. Cleanups, documentation, extension of
   mmap_prepare into filesystem drivers

 - "mm/huge_memory: refactor zap_huge_pmd()" (Lorenzo Stoakes)

   Simplify and clean up zap_huge_pmd(). Additional cleanups around
   vm_normal_folio_pmd() and the softleaf functionality are performed.

* tag 'mm-stable-2026-04-13-21-45' of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm: (369 commits)
  mm: fix deferred split queue races during migration
  mm/khugepaged: fix issue with tracking lock
  mm/huge_memory: add and use has_deposited_pgtable()
  mm/huge_memory: add and use normal_or_softleaf_folio_pmd()
  mm: add softleaf_is_valid_pmd_entry(), pmd_to_softleaf_folio()
  mm/huge_memory: separate out the folio part of zap_huge_pmd()
  mm/huge_memory: use mm instead of tlb->mm
  mm/huge_memory: remove unnecessary sanity checks
  mm/huge_memory: deduplicate zap deposited table call
  mm/huge_memory: remove unnecessary VM_BUG_ON_PAGE()
  mm/huge_memory: add a common exit path to zap_huge_pmd()
  mm/huge_memory: handle buggy PMD entry in zap_huge_pmd()
  mm/huge_memory: have zap_huge_pmd return a boolean, add kdoc
  mm/huge: avoid big else branch in zap_huge_pmd()
  mm/huge_memory: simplify vma_is_specal_huge()
  mm: on remap assert that input range within the proposed VMA
  mm: add mmap_action_map_kernel_pages[_full]()
  uio: replace deprecated mmap hook with mmap_prepare in uio_info
  drivers: hv: vmbus: replace deprecated mmap hook with mmap_prepare
  mm: allow handling of stacked mmap_prepare hooks in more drivers
  ...
2026-04-15 12:59:16 -07:00
Linus Torvalds
f5ad410100 Merge tag 'bpf-next-7.1' of git://git.kernel.org/pub/scm/linux/kernel/git/bpf/bpf-next
Pull bpf updates from Alexei Starovoitov:

 - Welcome new BPF maintainers: Kumar Kartikeya Dwivedi, Eduard
   Zingerman while Martin KaFai Lau reduced his load to Reviwer.

 - Lots of fixes everywhere from many first time contributors. Thank you
   All.

 - Diff stat is dominated by mechanical split of verifier.c into
   multiple components:

    - backtrack.c: backtracking logic and jump history
    - states.c:    state equivalence
    - cfg.c:       control flow graph, postorder, strongly connected
                   components
    - liveness.c:  register and stack liveness
    - fixups.c:    post-verification passes: instruction patching, dead
                   code removal, bpf_loop inlining, finalize fastcall

   8k line were moved. verifier.c still stands at 20k lines.

   Further refactoring is planned for the next release.

 - Replace dynamic stack liveness with static stack liveness based on
   data flow analysis.

   This improved the verification time by 2x for some programs and
   equally reduced memory consumption. New logic is in liveness.c and
   supported by constant folding in const_fold.c (Eduard Zingerman,
   Alexei Starovoitov)

 - Introduce BTF layout to ease addition of new BTF kinds (Alan Maguire)

 - Use kmalloc_nolock() universally in BPF local storage (Amery Hung)

 - Fix several bugs in linked registers delta tracking (Daniel Borkmann)

 - Improve verifier support of arena pointers (Emil Tsalapatis)

 - Improve verifier tracking of register bounds in min/max and tnum
   domains (Harishankar Vishwanathan, Paul Chaignon, Hao Sun)

 - Further extend support for implicit arguments in the verifier (Ihor
   Solodrai)

 - Add support for nop,nop5 instruction combo for USDT probes in libbpf
   (Jiri Olsa)

 - Support merging multiple module BTFs (Josef Bacik)

 - Extend applicability of bpf_kptr_xchg (Kaitao Cheng)

 - Retire rcu_trace_implies_rcu_gp() (Kumar Kartikeya Dwivedi)

 - Support variable offset context access for 'syscall' programs (Kumar
   Kartikeya Dwivedi)

 - Migrate bpf_task_work and dynptr to kmalloc_nolock() (Mykyta
   Yatsenko)

 - Fix UAF in in open-coded task_vma iterator (Puranjay Mohan)

* tag 'bpf-next-7.1' of git://git.kernel.org/pub/scm/linux/kernel/git/bpf/bpf-next: (241 commits)
  selftests/bpf: cover short IPv4/IPv6 inputs with adjust_room
  bpf: reject short IPv4/IPv6 inputs in bpf_prog_test_run_skb
  selftests/bpf: Use memfd_create instead of shm_open in cgroup_iter_memcg
  selftests/bpf: Add test for cgroup storage OOB read
  bpf: Fix OOB in pcpu_init_value
  selftests/bpf: Fix reg_bounds to match new tnum-based refinement
  selftests/bpf: Add tests for non-arena/arena operations
  bpf: Allow instructions with arena source and non-arena dest registers
  bpftool: add missing fsession to the usage and docs of bpftool
  docs/bpf: add missing fsession attach type to docs
  bpf: add missing fsession to the verifier log
  bpf: Move BTF checking logic into check_btf.c
  bpf: Move backtracking logic to backtrack.c
  bpf: Move state equivalence logic to states.c
  bpf: Move check_cfg() into cfg.c
  bpf: Move compute_insn_live_regs() into liveness.c
  bpf: Move fixup/post-processing logic from verifier.c into fixups.c
  bpf: Simplify do_check_insn()
  bpf: Move checks for reserved fields out of the main pass
  bpf: Delete unused variable
  ...
2026-04-14 18:04:04 -07:00
Alan Maguire
7419fcadd1 libbpf: Allow use of feature cache for non-token cases
Allow bpf object feat_cache assignment in BPF selftests
to simulate missing features via inclusion of libbpf_internal.h
and use of bpf_object_set_feat_cache() and bpf_object__sanitize_btf() to
test BTF sanitization for cases where missing features are simulated.

Signed-off-by: Alan Maguire <alan.maguire@oracle.com>
Link: https://lore.kernel.org/r/20260408165735.843763-2-alan.maguire@oracle.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
2026-04-10 12:34:36 -07:00
Weiming Shi
1c22483a2c bpf: reject negative CO-RE accessor indices in bpf_core_parse_spec()
CO-RE accessor strings are colon-separated indices that describe a path
from a root BTF type to a target field, e.g. "0:1:2" walks through
nested struct members. bpf_core_parse_spec() parses each component with
sscanf("%d"), so negative values like -1 are silently accepted.  The
subsequent bounds checks (access_idx >= btf_vlen(t)) only guard the
upper bound and always pass for negative values because C integer
promotion converts the __u16 btf_vlen result to int, making the
comparison (int)(-1) >= (int)(N) false for any positive N.

When -1 reaches btf_member_bit_offset() it gets cast to u32 0xffffffff,
producing an out-of-bounds read far past the members array.  A crafted
BPF program with a negative CO-RE accessor on any struct that exists in
vmlinux BTF (e.g. task_struct) crashes the kernel deterministically
during BPF_PROG_LOAD on any system with CONFIG_DEBUG_INFO_BTF=y
(default on major distributions).  The bug is reachable with CAP_BPF:

 BUG: unable to handle page fault for address: ffffed11818b6626
 #PF: supervisor read access in kernel mode
 #PF: error_code(0x0000) - not-present page
 Oops: Oops: 0000 [#1] SMP KASAN NOPTI
 CPU: 0 UID: 0 PID: 85 Comm: poc Not tainted 7.0.0-rc6 #18 PREEMPT(full)
 RIP: 0010:bpf_core_parse_spec (tools/lib/bpf/relo_core.c:354)
 RAX: 00000000ffffffff
 Call Trace:
  <TASK>
  bpf_core_calc_relo_insn (tools/lib/bpf/relo_core.c:1321)
  bpf_core_apply (kernel/bpf/btf.c:9507)
  check_core_relo (kernel/bpf/verifier.c:19475)
  bpf_check (kernel/bpf/verifier.c:26031)
  bpf_prog_load (kernel/bpf/syscall.c:3089)
  __sys_bpf (kernel/bpf/syscall.c:6228)
  </TASK>

CO-RE accessor indices are inherently non-negative (struct member index,
array element index, or enumerator index), so reject them immediately
after parsing.

Fixes: ddc7c30426 ("libbpf: implement BPF CO-RE offset relocation algorithm")
Reported-by: Xiang Mei <xmei5@asu.edu>
Signed-off-by: Weiming Shi <bestswngs@gmail.com>
Reviewed-by: Emil Tsalapatis <emil@etsalapatis.com>
Acked-by: Paul Chaignon <paul.chaignon@gmail.com>
Link: https://lore.kernel.org/r/20260404161221.961828-2-bestswngs@gmail.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
2026-04-07 08:27:55 -07:00