linux.git/tools/lib, branch v6.16-rc2

libbpf: Handle unsupported mmap-based /sys/kernel/btf/vmlinux correctly

2025-06-06T21:07:07+00:00

libbpf_err_ptr() helpers are meant to return NULL and set errno, if
there is an error. But btf_parse_raw_mmap() is meant to be used
internally and is expected to return ERR_PTR() values. Because of this
mismatch, when libbpf tries to mmap /sys/kernel/btf/vmlinux, we don't
detect the error correctly with IS_ERR() check, and never fallback to
old non-mmap-based way of loading vmlinux BTF.

Fix this by using proper ERR_PTR() returns internally.

Reported-by: Arnaldo Carvalho de Melo 
Reviewed-by: Arnaldo Carvalho de Melo 
Tested-by: Arnaldo Carvalho de Melo 
Fixes: 3c0421c93ce4 ("libbpf: Use mmap to parse vmlinux BTF from sysfs")
Cc: Lorenz Bauer 
Signed-off-by: Andrii Nakryiko 
Link: https://lore.kernel.org/r/20250606202134.2738910-1-andrii@kernel.org
Signed-off-by: Alexei Starovoitov

Merge tag 'perf-tools-for-v6.16-1-2025-06-03' of git://git.kernel.org/pub/scm/linux/kernel/git/perf/perf-tools

2025-06-03T22:11:44+00:00

Pull perf tools updates from Arnaldo Carvalho de Melo:
 "perf report/top/annotate TUI:

   - Accept the left arrow key as a Zoom out if done on the first column

   - Show if source code toggle status in title, to help spotting bugs
     with the various disassemblers (capstone, llvm, objdump)

   - Provide feedback on unhandled hotkeys

  Build:

   - Better inform when certain features are not available with warnings
     in the build process and in 'perf version --build-options' or 'perf -vv'

  perf record:

   - Improve the --off-cpu code by synthesizing events for switch-out ->
     switch-in intervals using a BPF program. This can be fine tuned
     using a --off-cpu-thresh knob

  perf report:

   - Add 'tgid' sort key

  perf mem/c2c:

   - Add 'op', 'cache', 'snoop', 'dtlb' output fields

   - Add support for 'ldlat' on AMD IBS (Instruction Based Sampling)

  perf ftrace:

   - Use process/session specific trace settings instead of messing with
     the global ftrace knobs

  perf trace:

   - Implement syscall summary in BPF

   - Support --summary-mode=cgroup

   - Always print return value for syscalls returning a pid

   - The rseq and set_robust_list don't return a pid, just -errno

  perf lock contention:

   - Symbolize zone->lock using BTF

   - Add -J/--inject-delay option to estimate impact on application
     performance by optimization of kernel locking behavior

  perf stat:

   - Improve hybrid support for the NMI watchdog warning

  Symbol resolution:

   - Handle 'u' and 'l' symbols in /proc/kallsyms, resolving some Rust
     symbols

   - Improve Rust demangler

  Hardware tracing:

  Intel PT:

   - Fix PEBS-via-PT data_src

   - Do not default to recording all switch events

   - Fix pattern matching with python3 on the SQL viewer script

  arm64:

   - Fixups for the hip08 hha PMU

  Vendor events:

   - Update Intel events/metrics files for alderlake, alderlaken,
     arrowlake, bonnell, broadwell, broadwellde, broadwellx,
     cascadelakex, clearwaterforest, elkhartlake, emeraldrapids,
     grandridge, graniterapids, haswell, haswellx, icelake, icelakex,
     ivybridge, ivytown, jaketown, lunarlake, meteorlake, nehalemep,
     nehalemex, rocketlake, sandybridge, sapphirerapids, sierraforest,
     skylake, skylakex, snowridgex, tigerlake, westmereep-dp,
     westmereep-sp, westmereep-sx

  python support:

   - Add support for event counts in the python binding, add a
     counting.py example

  perf list:

   - Display the PMU name associated with a perf metric in JSON

  perf test:

   - Hybrid improvements for metric value validation test

   - Fix LBR test by ignoring idle task

   - Add AMD IBS sw filter ana d'ldlat' tests

   - Add 'perf trace --summary-mode=cgroup' test

   - Add tests for the various language symbol demanglers

  Miscellaneous:

   - Allow specifying the cpu an event will be tied using '-e
     event/cpu=N/'

   - Sync various headers with the kernel sources

   - Add annotations to use clang's -Wthread-safety and fix some
     problems it detected

   - Make dump_stack() use perf's symbol resolution to provide better
     backtraces

   - Intel TPEBS support cleanups and fixes. TPEBS stands for Timed PEBS
     (Precision Event-Based Sampling), that adds timing info, the
     retirement latency of instructions

   - Various memory allocation (some detected by ASAN) and reference
     counting fixes

   - Add a 8-byte aligned PERF_RECORD_COMPRESSED2 to replace
     PERF_RECORD_COMPRESSED

   - Skip unsupported event types in perf.data files, don't stop when
     finding one

   - Improve lookups using hashmaps and binary searches"

* tag 'perf-tools-for-v6.16-1-2025-06-03' of git://git.kernel.org/pub/scm/linux/kernel/git/perf/perf-tools: (206 commits)
  perf callchain: Always populate the addr_location map when adding IP
  perf lock contention: Reject more than 10ms delays for safety
  perf trace: Set errpid to false for rseq and set_robust_list
  perf symbol: Move demangling code out of symbol-elf.c
  perf trace: Always print return value for syscalls returning a pid
  perf script: Print PERF_AUX_FLAG_COLLISION flag
  perf mem: Show absolute percent in mem_stat output
  perf mem: Display sort order only if it's available
  perf mem: Describe overhead calculation in brief
  perf record: Fix incorrect --user-regs comments
  Revert "perf thread: Ensure comm_lock held for comm_list"
  perf test trace_summary: Skip --bpf-summary tests if no libbpf
  perf test intel-pt: Skip jitdump test if no libelf
  perf intel-tpebs: Avoid race when evlist is being deleted
  perf test demangle-java: Don't segv if demangling fails
  perf symbol: Fix use-after-free in filename__read_build_id
  perf pmu: Avoid segv for missing name/alias_name in wildcarding
  perf machine: Factor creating a "live" machine out of dwarf-unwind
  perf test: Add AMD IBS sw filter test
  perf mem: Count L2 HITM for c2c statistic
  ...

Merge tag 'bpf-next-6.16' of git://git.kernel.org/pub/scm/linux/kernel/git/bpf/bpf-next

2025-05-28T22:52:42+00:00

Pull bpf updates from Alexei Starovoitov:

 - Fix and improve BTF deduplication of identical BTF types (Alan
   Maguire and Andrii Nakryiko)

 - Support up to 12 arguments in BPF trampoline on arm64 (Xu Kuohai and
   Alexis Lothoré)

 - Support load-acquire and store-release instructions in BPF JIT on
   riscv64 (Andrea Parri)

 - Fix uninitialized values in BPF_{CORE,PROBE}_READ macros (Anton
   Protopopov)

 - Streamline allowed helpers across program types (Feng Yang)

 - Support atomic update for hashtab of BPF maps (Hou Tao)

 - Implement json output for BPF helpers (Ihor Solodrai)

 - Several s390 JIT fixes (Ilya Leoshkevich)

 - Various sockmap fixes (Jiayuan Chen)

 - Support mmap of vmlinux BTF data (Lorenz Bauer)

 - Support BPF rbtree traversal and list peeking (Martin KaFai Lau)

 - Tests for sockmap/sockhash redirection (Michal Luczaj)

 - Introduce kfuncs for memory reads into dynptrs (Mykyta Yatsenko)

 - Add support for dma-buf iterators in BPF (T.J. Mercier)

 - The verifier support for __bpf_trap() (Yonghong Song)

* tag 'bpf-next-6.16' of git://git.kernel.org/pub/scm/linux/kernel/git/bpf/bpf-next: (135 commits)
  bpf, arm64: Remove unused-but-set function and variable.
  selftests/bpf: Add tests with stack ptr register in conditional jmp
  bpf: Do not include stack ptr register in precision backtracking bookkeeping
  selftests/bpf: enable many-args tests for arm64
  bpf, arm64: Support up to 12 function arguments
  bpf: Check rcu_read_lock_trace_held() in bpf_map_lookup_percpu_elem()
  bpf: Avoid __bpf_prog_ret0_warn when jit fails
  bpftool: Add support for custom BTF path in prog load/loadall
  selftests/bpf: Add unit tests with __bpf_trap() kfunc
  bpf: Warn with __bpf_trap() kfunc maybe due to uninitialized variable
  bpf: Remove special_kfunc_set from verifier
  selftests/bpf: Add test for open coded dmabuf_iter
  selftests/bpf: Add test for dmabuf_iter
  bpf: Add open coded dmabuf iterator
  bpf: Add dmabuf iterator
  dma-buf: Rename debugfs symbols
  bpf: Fix error return value in bpf_copy_from_user_dynptr
  libbpf: Use mmap to parse vmlinux BTF from sysfs
  selftests: bpf: Add a test for mmapable vmlinux BTF
  btf: Allow mmap of vmlinux btf
  ...

libbpf: Use mmap to parse vmlinux BTF from sysfs

2025-05-23T17:06:28+00:00

Teach libbpf to use mmap when parsing vmlinux BTF from /sys. We don't
apply this to fall-back paths on the regular file system because there
is no way to ensure that modifications underlying the MAP_PRIVATE
mapping are not visible to the process.

Signed-off-by: Lorenz Bauer 
Signed-off-by: Andrii Nakryiko 
Tested-by: Alan Maguire 
Acked-by: Andrii Nakryiko 
Link: https://lore.kernel.org/bpf/20250520-vmlinux-mmap-v5-3-e8c941acc414@isovalent.com

libperf threadmap: Add perf_thread_map__idx()

2025-05-21T18:07:13+00:00

Allow computation of thread map index from a PID.

Note, with a 'struct perf_cpu_map' the sorted nature allows for a binary
search to compute the index which isn't currently possible with a
'struct perf_thread_map' as they aren't guaranteed sorted.

Signed-off-by: Ian Rogers 
Acked-by: Gautam Menghani 
Tested-by: Arnaldo Carvalho de Melo 
Cc: Adrian Hunter 
Cc: Alexander Shishkin 
Cc: Howard Chu 
Cc: Ingo Molnar 
Cc: Jiri Olsa 
Cc: Kan Liang 
Cc: Madhavan Srinivasan 
Cc: Mark Rutland 
Cc: Namhyung Kim 
Cc: Peter Zijlstra 
Link: https://lore.kernel.org/r/20250519195148.1708988-3-irogers@google.com
Signed-off-by: Arnaldo Carvalho de Melo

libperf threadmap: Don't segv for index 0 for the NULL 'struct perf_thread_map' pointer

2025-05-21T18:07:13+00:00

perf_thread_map__nr() returns length 1 if the perf_thread_map is NULL,
meaning index 0 is valid.

When perf_thread_map__pid() of index 0 is read then return the expected
"any" -1 value.

Assert this is only done for index 0.

Signed-off-by: Ian Rogers 
Acked-by: Gautam Menghani 
Tested-by: Arnaldo Carvalho de Melo 
Cc: Adrian Hunter 
Cc: Alexander Shishkin 
Cc: Howard Chu 
Cc: Ingo Molnar 
Cc: Jiri Olsa 
Cc: Kan Liang 
Cc: Madhavan Srinivasan 
Cc: Mark Rutland 
Cc: Namhyung Kim 
Cc: Peter Zijlstra 
Link: https://lore.kernel.org/r/20250519195148.1708988-2-irogers@google.com
Signed-off-by: Arnaldo Carvalho de Melo

libbpf/btf: Fix string handling to support multi-split BTF

2025-05-20T23:22:30+00:00

libbpf handling of split BTF has been written largely with the
assumption that multiple splits are possible, i.e. split BTF on top of
split BTF on top of base BTF.  One area where this does not quite work
is string handling in split BTF; the start string offset should be the
base BTF string section length + the base BTF string offset.  This
worked in the past because for a single split BTF with base the start
string offset was always 0.

Signed-off-by: Alan Maguire 
Signed-off-by: Andrii Nakryiko 
Link: https://lore.kernel.org/bpf/20250519165935.261614-2-alan.maguire@oracle.com

perf record: Add 8-byte aligned event type PERF_RECORD_COMPRESSED2

2025-05-16T20:31:40+00:00

The original PERF_RECORD_COMPRESS is not 8-byte aligned, which can cause
asan runtime error:

  # Build with asan
  $ make -C tools/perf O=/tmp/perf DEBUG=1 EXTRA_CFLAGS="-O0 -g -fno-omit-frame-pointer -fsanitize=undefined"
  # Test success with many asan runtime errors:
  $ /tmp/perf/perf test "Zstd perf.data compression/decompression" -vv
   83: Zstd perf.data compression/decompression:
  ...
  util/session.c:1959:13: runtime error: member access within misaligned address 0x7f69e3f99653 for type 'union perf_event', which requires 13 byte alignment
  0x7f69e3f99653: note: pointer points here
   d0  3a 50 69 44 00 00 00 00  00 08 00 bb 07 00 00 00  00 00 00 44 00 00 00 00  00 00 00 ff 07 00 00
                ^
  util/session.c:2163:22: runtime error: member access within misaligned address 0x7f69e3f99653 for type 'union perf_event', which requires 8 byte alignment
  0x7f69e3f99653: note: pointer points here
   d0  3a 50 69 44 00 00 00 00  00 08 00 bb 07 00 00 00  00 00 00 44 00 00 00 00  00 00 00 ff 07 00 00
                ^
  ...

Since there is no way to align compressed data in zstd compression, this
patch add a new event type `PERF_RECORD_COMPRESSED2`, which adds a field
`data_size` to specify the actual compressed data size.

The `header.size` contains the total record size, including the padding
at the end to make it 8-byte aligned.

Tested with `Zstd perf.data compression/decompression`

Signed-off-by: Chun-Tse Shao 
Tested-by: Arnaldo Carvalho de Melo 
Cc: Adrian Hunter 
Cc: Alexander Shishkin 
Cc: Ben Gainey 
Cc: Christophe Leroy 
Cc: Ian Rogers 
Cc: Ingo Molnar 
Cc: James Clark 
Cc: Jiri Olsa 
Cc: Kan Liang 
Cc: Leo Yan 
Cc: Mark Rutland 
Cc: Namhyung Kim 
Cc: Nick Terrell 
Cc: Peter Zijlstra 
Link: https://lore.kernel.org/r/20250303183646.327510-1-ctshao@google.com
Signed-off-by: Arnaldo Carvalho de Melo

libbpf: Check bpf_map_skeleton link for NULL

2025-05-14T16:30:06+00:00

Avoid dereferencing bpf_map_skeleton's link field if it's NULL.
If BPF map skeleton is created with the size, that indicates containing
link field, but the field was not actually initialized with valid
bpf_link pointer, libbpf crashes. This may happen when using libbpf-rs
skeleton.
Skeleton loading may still progress, but user needs to attach struct_ops
map separately.

Signed-off-by: Mykyta Yatsenko 
Signed-off-by: Andrii Nakryiko 
Link: https://lore.kernel.org/bpf/20250514113220.219095-1-mykyta.yatsenko5@gmail.com

libbpf: Use proper errno value in nlattr

2025-05-12T22:22:54+00:00

Return value of the validate_nla() function can be propagated all the
way up to users of libbpf API. In case of error this libbpf version
of validate_nla returns -1 which will be seen as -EPERM from user's
point of view. Instead, return a more reasonable -EINVAL.

Fixes: bbf48c18ee0c ("libbpf: add error reporting in XDP")
Suggested-by: Andrii Nakryiko 
Signed-off-by: Anton Protopopov 
Signed-off-by: Andrii Nakryiko 
Link: https://lore.kernel.org/bpf/20250510182011.2246631-1-a.s.protopopov@gmail.com