Modify bounds and union member access in mmap2 build_id synthesis. Bound
max_filename_len against the minimum of filename array capacity and the
outer union stack layout minus sample ID trailers. This prevents both
-E2BIG overruns and _FORTIFY_SOURCE array bounds aborts on strlcpy even
if the enclosing union expands.
Assisted-by: Antigravity:gemini-3.5-flash
Signed-off-by: Ian Rogers <irogers@google.com>
Signed-off-by: Namhyung Kim <namhyung@kernel.org>
Clamp long DSO names to mmap/mmap2 filename boundaries accounting for
sample ID headers to prevent buffer overruns in
perf_event__synthesize_modules_maps_cb(). Explicitly clear misc flags and
union padding to prevent stale Build-ID state from leaking between module
synthesis events, and cast event buffer pointers to avoid _FORTIFY_SOURCE
array bounds aborts when zeroing padding trailers.
Assisted-by: Antigravity:gemini-3.5-flash
Signed-off-by: Ian Rogers <irogers@google.com>
Signed-off-by: Namhyung Kim <namhyung@kernel.org>
Fix a pre-existing stack buffer overflow bug in
perf_event__synthesize_cgroup() where an in-place null padding loop wrote
bytes past the end of the cgrp_root stack array buffer during cgroup tree
traversal. Eliminate in-place path mutation, use PERF_ALIGN for path_len,
clamp raw_path_len to prevent sample ID header trailer overruns, and use
strlcpy with combined zero padding for alignment and sample ID headers.
Assisted-by: Antigravity:gemini-3.5-flash
Signed-off-by: Ian Rogers <irogers@google.com>
Signed-off-by: Namhyung Kim <namhyung@kernel.org>
Fix critical logic and boundary bugs in read_proc_maps_line() and caller.
Ensure any mid-line hex/dec/char parsing failure invokes io__drain_line()
safely, using a do-while loop to read and discard remaining characters
until a newline or EOF is reached. Clamp pathname extraction size to
account for trailing sample ID headers, use standard '//toolong' fallback
literal for over-length pathnames, emit timeout flags for truncated entries
securely via goto out;, and cast event buffer pointers to avoid
_FORTIFY_SOURCE array bounds aborts across synthesis handlers.
Assisted-by: Antigravity:gemini-3.5-flash
Signed-off-by: Ian Rogers <irogers@google.com>
Signed-off-by: Namhyung Kim <namhyung@kernel.org>
Use getline() to dynamically allocate the required line buffer for maps
parsing, guaranteeing bounds safety and avoiding compiler warnings
by evaluating the return value in the loop condition directly.
Assisted-by: Antigravity:gemini-3.5-flash
Signed-off-by: Ian Rogers <irogers@google.com>
Signed-off-by: Namhyung Kim <namhyung@kernel.org>
skip() ignores do_read()'s return value and unconditionally
subtracts the requested chunk size from 'size' on every iteration.
This was previously bounded by size being 'int': a maliciously
large 64-bit value was truncated on assignment, capping the loop
early by accident.
Now that size is size_t, a crafted file supplying a very large
size causes skip() to keep requesting BUFSIZ-sized reads and
subtracting BUFSIZ from size regardless of whether do_read()
actually succeeds, spinning indefinitely even after EOF or a read
error.
Check do_read()'s return value and break out of the loop on
failure or EOF, so forward progress is only counted when a read
actually succeeds.
Signed-off-by: Tanushree Shah <tshah@linux.ibm.com>
Signed-off-by: Namhyung Kim <namhyung@kernel.org>
Both functions read an attacker-controlled size directly from the
input file and pass size + 1 to malloc() before reading size bytes
into the result:
read_ftrace_printk(): size is an unsigned int from read4(). When
size == UINT_MAX, size + 1 overflows to 0, so malloc(0) returns a
minimal allocation while size itself remains UINT_MAX.
read_saved_cmdline(): size is an unsigned long long from read8().
When size == ULLONG_MAX, size + 1 overflows to 0 the same way.
In both cases, do_read(buf, size) then attempts to read the full,
unwrapped size into the tiny allocated buffer, a heap buffer
overflow.
This was previously masked by do_read()'s size parameter being
'int': passing these values truncated them, which the read()
syscall's own boundary checks rejected before any data was read.
Fixing that truncation (widening do_read() to size_t) is correct
on its own, but it removes this accidental protection and exposes
the pre-existing missing bounds check in both functions.
Reject the one value that causes the overflow before it's used, in
each function.
Signed-off-by: Tanushree Shah <tshah@linux.ibm.com>
Signed-off-by: Namhyung Kim <namhyung@kernel.org>
trace_event__cleanup() frees t->pevent but never clears the
pointer. It can be called twice on the same trace_event: once
from trace_report()'s error path, and again from
perf_session__delete() during session teardown, resulting in a
double free / use-after-free.
Separately, trace_event__init() overwrites t->pevent/t->plugin_list
without releasing any existing handle, leaking memory if it's
called more than once on the same struct. eg. via a perf.data
file with multiple PERF_RECORD_HEADER_TRACING_DATA headers.
Guard against re-entry by returning early if t->pevent is already
NULL, and clear it after cleanup so a repeat call is a safe no-op.
Call trace_event__cleanup() at the start of trace_event__init(),
so a repeated init releases any existing handle before allocating
a new one.
Signed-off-by: Tanushree Shah <tshah@linux.ibm.com>
Signed-off-by: Namhyung Kim <namhyung@kernel.org>
The do_read() and skip() functions use 'int' for size parameters,
truncating 64-bit sizes from callers. This causes two issues:
1. Uninitialized memory dump: do_read() reads fewer bytes than
allocated, leaving uninitialized heap memory that gets written
to output files.
2. Out-of-bounds read: Parsing functions process the full 64-bit
size while only partial data was read into the buffer.
Change do_read(), __do_read(), and skip() to use size_t for size
parameters and ssize_t for return values (where applicable), matching
read()/write() system calls.
Update callers to use ssize_t for storing return values.
Fixes: 4a31e56599 ("perf tools: Get rid of read_or_die() in trace-event-read.c")
Signed-off-by: Tanushree Shah <tshah@linux.ibm.com>
Signed-off-by: Namhyung Kim <namhyung@kernel.org>
read_string() writes into buf[BUFSIZ] one byte at a time without
checking 'size' against the buffer bound before each write. A
string longer than BUFSIZ in the input overflows the stack buffer.
Add a bounds check before each write to prevent overflow. On
overflow the function returns NULL, matching its other error paths.
Fixes: 9215545e99 ("perf: Convert perf tracing data into a tracing_data event")
Signed-off-by: Tanushree Shah <tshah@linux.ibm.com>
Signed-off-by: Namhyung Kim <namhyung@kernel.org>
When c2c_hists__init() or c2c_hists__reinit() calls hpp_list__parse()
and it fails partway through, format structures registered via
perf_hpp_list__column_register() and perf_hpp_list__register_sort_field()
are left on the hpp_list.
In c2c_hists__init(), only one of the callers, c2c_he__alloc_hists(),
handled this with perf_hpp__reset_output_field(), while perf_c2c_report()
did not, leaking the partially registered entries.
In c2c_hists__reinit(), neither perf_c2c_report() nor resort_cl_cb()
clean up on failure.
Fix by adding cleanup inside both functions themselves, so all callers
are protected, and remove the now redundant reset in c2c_he__alloc_hists().
Fixes: 78b2754378 ("perf c2c report: Add sample processing")
Reported-by: sashiko-bot <sashiko-bot@kernel.org>
Cc: Jiri Olsa <jolsa@kernel.org>
Assisted-by: Claude:claude-opus-4.6
Assisted-by: Opencode:mimo-v2.5-free
Assisted-by: Opencode:DeepSeek-V4-Flash-free
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Reviewed-by: Ian Rogers <irogers@google.com>
Signed-off-by: Namhyung Kim <namhyung@kernel.org>
hpp_list__parse() has three bugs:
1. The PARSE_LIST macro resets ret = 0 at the start of each invocation,
so an error from output parsing is silently overwritten when the sort
parsing block runs. The function returns success with partially
initialized state.
2. When the caller passes a non-NULL output_ or sort_ string, but
strdup() returns NULL due to OOM, NULL is passed to PARSE_LIST which
treats it as empty input (the "if (!_list) break" branch). No error
is returned.
3. When the called _fn function fails and returns something other than
-ESRCH or -EINVAL (-ENOMEM, for instance) it was not bailing out of
the strtok loop.
Fix them by checking strdup() return values before proceeding and adding
a cleanup label so that ret from each PARSE_LIST call is checked before
the next runs, preserving the first error.
The early exits now skip perf_hpp__setup_output_field(), which means
c2c_hists__reinit() can return a non-zero value in cases that previously
always succeeded silently. Both callers discarded its return:
resort_cl_cb() continued into hists__collapse_resort() on a broken list,
and perf_c2c__report() proceeded with uninitialised hists. Fix the full
chain: check and propagate the error in resort_cl_cb() -- hists__iterate_cb()
already stops iteration and returns the callback error -- and check both
c2c_hists__reinit() and hists__iterate_cb() in perf_c2c__report().
Also turn PARSE_LIST into a function, using a switch to catch other
errors, converting the called functions to return an appropriate errno
instead of -1 on failure.
Also make the two callers that iterate sort_dimension__add() and
output_field_add() handle the newly propagated errors: setup_sort_list()
and setup_output_list() only checked for -EINVAL and -ESRCH, so an
-ENOMEM from a failed allocation was silently overwritten by the next
loop iteration. Break out of the loop and propagate any other error.
The hpp_list__parse() fixes were developed with AI assistance from
Claude:claude-sonnet-4.6, and the setup_sort_list()/setup_output_list()
caller fixes with AI assistance from Opencode:mimo-v2.5-free and
Opencode:DeepSeek-V4-Flash-free.
Fixes: 2d388bd0c9 ("perf c2c report: Add stdio output support")
Reported-by: sashiko-bot <sashiko-bot@kernel.org>
Cc: Jiri Olsa <jolsa@kernel.org>
Assisted-by: Claude:claude-sonnet-4.6
Assisted-by: Opencode:mimo-v2.5-free
Assisted-by: Opencode:DeepSeek-V4-Flash-free
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Reviewed-by: Ian Rogers <irogers@google.com>
Signed-off-by: Namhyung Kim <namhyung@kernel.org>
symbol__disassemble_bpf_libbfd() has four resource management bugs:
1. free(prog_linfo) leaks internal arrays. bpf_prog_linfo contains
raw_linfo, raw_jited_linfo, nr_jited_linfo_per_func, and
jited_linfo_func_idx pointers that are only freed by the proper
destructor bpf_prog_linfo__free().
2. open_memstream(&buf, &buf_size) allocates a dynamic buffer that the
caller must free after fclose(). The function calls fclose(s) but
never free(buf), leaking the stream buffer on every call.
3. args->line = strdup(srcline) is immediately consumed by
disasm_line__new(args) which internally calls strdup(args->line)
again via annotation_line__init(). The first strdup result is then
overwritten by args->line = buf + prev_buf_size without being freed.
4. If open_memstream() fails, the error path jumps to 'out:' which
calls fclose(s) with s == NULL — undefined behavior.
Fix by using bpf_prog_linfo__free(), initializing buf to NULL, adding
free(buf) after fclose(s), guarding fclose() against NULL, and removing
the redundant strdup since annotation_line__init() makes its own copy.
Fixes: 6987561c9e ("perf annotate: Enable annotation of BPF programs")
Reported-by: sashiko-bot <sashiko-bot@kernel.org>
Cc: Song Liu <songliubraving@fb.com>
Reviewed-by: Ian Rogers <irogers@google.com>
Assisted-by: Claude:claude-opus-4.6
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Signed-off-by: Namhyung Kim <namhyung@kernel.org>
synthesize_bpf_prog_name() unconditionally dereferences prog_tags[sub_id]
(line: u8 (*prog_tags)[BPF_TAG_SIZE] = (void *)(uintptr_t)(info->prog_tags))
but __bpf_event__print_bpf_prog_info() only requires JITED_KSYMS and
JITED_FUNC_LENS in its required_arrays bitmask.
If a crafted perf.data has the PROG_TAGS bit cleared (or the array was
invalidated by bpil_offs_to_addr() bounds checking), info->prog_tags
contains either zero or a raw file offset. Dereferencing it causes a
NULL pointer dereference or an arbitrary memory read.
Add PERF_BPIL_PROG_TAGS to required_arrays so the function returns early
when prog_tags was not present or failed validation.
Fixes: f8dfeae009 ("perf bpf: Show more BPF program info in print_bpf_prog_info()")
Reported-by: sashiko-bot <sashiko-bot@kernel.org>
Cc: Song Liu <songliubraving@fb.com>
Reviewed-by: Ian Rogers <irogers@google.com>
Assisted-by: Claude:claude-opus-4.6
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Signed-off-by: Namhyung Kim <namhyung@kernel.org>
write_bpf_prog_info() holds a read lock while temporarily mutating
info_linear via bpil_addr_to_offs()/bpil_offs_to_addr(). Between these
two calls, the pointers in info_linear contain file offsets instead of
heap addresses. Concurrent readers holding the same read lock see the
file offsets and dereference them as pointers.
Use down_write()/up_write() instead of down_read()/up_read() to exclude
concurrent readers during the addr-to-offset-to-addr translation window.
Fixes: 63ac7968a1fb ("perf bpf: Save bpf_prog_info information as headers to perf.data")
Reported-by: sashiko-bot <sashiko-bot@kernel.org>
Cc: Song Liu <songliubraving@fb.com>
Reviewed-by: Ian Rogers <irogers@google.com>
Assisted-by: Claude:claude-opus-4.6
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Signed-off-by: Namhyung Kim <namhyung@kernel.org>
symbol__disassemble_bpf_libbfd() casts info_linear->info.jited_prog_insns
and info_linear->info.jited_ksyms to pointers without checking whether
bpil_offs_to_addr() actually converted the file offsets. A crafted
perf.data with PERF_BPIL_* bits unset but non-zero counts causes raw
file offsets to be dereferenced as pointers.
Add bitmask checks for PERF_BPIL_JITED_INSNS and PERF_BPIL_JITED_KSYMS
before the casts, matching the validation added to bpf-event.c call
sites.
Fixes: 6987561c9e ("perf annotate: Enable annotation of BPF programs")
Reported-by: sashiko-bot <sashiko-bot@kernel.org>
Cc: Song Liu <songliubraving@fb.com>
Reviewed-by: Ian Rogers <irogers@google.com>
Assisted-by: Claude:claude-opus-4.6
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Signed-off-by: Namhyung Kim <namhyung@kernel.org>
Currently, when a probe event is added using perf probe --add with a
hexadecimal type cast (e.g., var:x64 and var:x32), the kernel traceprobe
subsystem sets the field type to "u64" in the event's format file, yet
generates a print format specifier of "var=0x%Lx" or "0x%x".
By default, perf trace uses its internal beautifiers which only inspect
field->type and field->flags. Because traceprobe events declare
primitive integer field types ("u64") without a C pointer asterisk
(i.e., "*"), perf trace defaults to printing the field's value as a
decimal unsigned long ("%ld"), ignoring the hexadecimal intent.
Introduce field_has_hex_fmt() to inspect the tracepoint's print_fmt
format string. If a field's print format assignment uses hexadecimal
specifiers (i.e., "=0x", "=%#", or "=%p"), assign SCA_PTR formatting so
perf trace displays the value in hexadecimal by default without
requiring --libtraceevent. For example:
❯ sudo ./perf probe --add 'enqueue_task_fair rq=rq:x64 p=p:x64 flags=flags:x32'
Added new event:
probe:enqueue_task_fair (on enqueue_task_fair with rq=rq:x64 p=p:x64 flags=flags:x32)
You can now use it in all perf tools, such as:
perf record -e probe:enqueue_task_fair -aR sleep 1
❯ sudo ./perf trace --show-cpu --event probe:enqueue_task_fair --max-event 3
0.000 [000] :0/0 probe:enqueue_task_fair(rq: 0xffff8ac632233180, p: 0xffff8ac2c1240000, flags: 0x100009)
0.006 [004] :0/0 probe:enqueue_task_fair(rq: 0xffff8ac632433180, p: 0xffff8ac624cf8000, flags: 0x9)
0.069 [001] :0/0 probe:enqueue_task_fair(rq: 0xffff8ac6322b3180, p: 0xffff8ac4c4212c40, flags: 0x9)
Signed-off-by: Aaron Tomlin <atomlin@atomlin.com>
Signed-off-by: Namhyung Kim <namhyung@kernel.org>
Based on offline discussion with Intel in
lore.kernel.org/20260715211144.3144895-1-ctshao@google.com, we decided
to drop the leading zero from Nova Lake models 0x01 and 0x03 in
mapfile.csv to match single-digit model numbers without zero padding
(GenuineIntel-18-[13]).
The updated mapfile entry was published in:
github.com/intel/perfmon/commit/00167baed45ac3b2708e89dbf1b9ce4769e9d115
Signed-off-by: Chun-Tse Shao <ctshao@google.com>
Reviewed-by: Dapeng Mi <dapeng1.mi@linux.intel.com>
Signed-off-by: Namhyung Kim <namhyung@kernel.org>
arm_spe__alloc_metadata() reads nr_cpu from the auxtrace_info priv
array without validation. When a crafted perf.data provides nr_cpu=0,
the per_cpu_sz calculation divides by zero:
per_cpu_sz = (metadata_size - (hdr_sz * sizeof(u64))) / (*nr_cpu);
Reject nr_cpu <= 0 early, before the division. The caller already
treats NULL return with metadata_ver != 1 as a parse failure.
Fixes: 7842a4b6ff ("perf arm-spe: Support metadata version 2")
Reported-by: sashiko-bot <sashiko-bot@kernel.org>
Assisted-by: Claude:claude-opus-4.6
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Reviewed-by: James Clark <james.clark@linaro.org>
Reviewed-by: Adrian Hunter <adrian.hunter@intel.com>
Signed-off-by: Namhyung Kim <namhyung@kernel.org>
Same pattern as the Intel PT fix: min_sz is set to
sizeof(u64) * INTEL_BTS_SNAPSHOT_MODE, but the code accesses
auxtrace_info->priv[INTEL_BTS_SNAPSHOT_MODE], which requires at least
INTEL_BTS_SNAPSHOT_MODE + 1 elements.
Use (INTEL_BTS_SNAPSHOT_MODE + 1) to ensure the highest accessed index
is within bounds.
Fixes: d0170af700 ("perf tools: Add Intel BTS support")
Reported-by: sashiko-bot <sashiko-bot@kernel.org>
Assisted-by: Claude:claude-opus-4.6
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Reviewed-by: James Clark <james.clark@linaro.org>
Reviewed-by: Adrian Hunter <adrian.hunter@intel.com>
Signed-off-by: Namhyung Kim <namhyung@kernel.org>
min_sz is set to sizeof(u64) * INTEL_PT_PER_CPU_MMAPS, but the code
accesses auxtrace_info->priv[INTEL_PT_PER_CPU_MMAPS], which requires
at least INTEL_PT_PER_CPU_MMAPS + 1 elements. A file with exactly
min_sz bytes of priv data passes the size check but the access reads
one u64 past the validated region.
Use (INTEL_PT_PER_CPU_MMAPS + 1) to ensure the highest accessed index
is within bounds.
Fixes: 90e457f7be ("perf tools: Add Intel PT support")
Reported-by: sashiko-bot <sashiko-bot@kernel.org>
Assisted-by: Claude:claude-opus-4.6
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Reviewed-by: James Clark <james.clark@linaro.org>
Reviewed-by: Adrian Hunter <adrian.hunter@intel.com>
Signed-off-by: Namhyung Kim <namhyung@kernel.org>
auxtrace_queues__grow() has two bugs:
1. When idx is UINT_MAX, the caller passes new_nr_queues = idx + 1 = 0.
The function skips growing (since any nr_queues >= 0), returns
success, and the caller accesses queue_array[UINT_MAX] — an OOB
heap write. Fix by rejecting new_nr_queues == 0 up front.
2. The function allocates a new queue_array via calloc and copies
elements from the old array, but never frees the old array. Fix
by saving the old pointer and freeing it after the copy.
Fixes: e502789302 ("perf auxtrace: Add helpers for queuing AUX area tracing data")
Reported-by: sashiko-bot <sashiko-bot@kernel.org>
Assisted-by: Claude:claude-opus-4.6
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Reviewed-by: James Clark <james.clark@linaro.org>
Reviewed-by: Adrian Hunter <adrian.hunter@intel.com>
Signed-off-by: Namhyung Kim <namhyung@kernel.org>
thread_stack__br_sample() copies the wrap-around portion of the branch
stack ring buffer with:
nr = min(ts->br_stack_pos, sz);
memcpy(be, &src->entries[0], bsz * ts->br_stack_pos);
'nr' is correctly bounded to min(br_stack_pos, sz) but the memcpy uses
the unbounded ts->br_stack_pos directly. When br_stack_pos exceeds
the remaining destination space 'sz', this writes past the destination
buffer.
Use 'nr' (the bounded value) in the memcpy size, matching the pattern
of the first memcpy in the same function.
Fixes: 86d67180b9 ("perf thread-stack: Add branch stack support")
Reported-by: sashiko-bot <sashiko-bot@kernel.org>
Assisted-by: Claude:claude-opus-4.6
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Reviewed-by: James Clark <james.clark@linaro.org>
Reviewed-by: Adrian Hunter <adrian.hunter@intel.com>
Signed-off-by: Namhyung Kim <namhyung@kernel.org>
The brief description of the idle-cycles-frontend legacy hardware event
refers to its alias as "stalled-cycles-fronted", but there is no such
event. The correct event name is "stalled-cycles-frontend".
This typo is visible in the output of "perf list", for example:
idle-cycles-frontend
[Stalled cycles during issue [This event is an alias of
stalled-cycles-fronted]. Unit: armv8_pmuv3]
Fix the spelling so that the description points to the valid event name.
Signed-off-by: Pu Hu <hupu@transsion.com>
Signed-off-by: Namhyung Kim <namhyung@kernel.org>
strsep() advances the pointer given to it. After the loop s is
either NULL (on success) or points mid buffer (early exit if malloc
fails) so the original buffer is never freed properly.
Fix by adding a tmp pointer for use by strsep and free the original
pointer
Signed-off-by: Michail Tatas <michail.tatas@gmail.com>
Signed-off-by: Namhyung Kim <namhyung@kernel.org>
The commit d7507a94a0 ("KVM: SVM: Treat exit_code as an unsigned
64-bit value through all of KVM") added "ull" suffix to SVM exit codes
and it makes the 32-bit build fail like below.
In file included from util/kvm-stat-arch/kvm-stat-x86.c:4:
util/kvm-stat-arch/../../../arch/x86/include/uapi/asm/svm.h:137:32:
error: conversion from 'long long unsigned int' to 'long unsigned int' changes
value from '18446744073709551615' to '4294967295' [-Werror=overflow]
137 | #define SVM_EXIT_ERR -1ull
| ^
util/kvm-stat-arch/../kvm-stat.h:131:17: note: in definition of macro 'define_exit_reasons_table'
131 | symbols, { -1, NULL } \
| ^~~~~~~
util/kvm-stat-arch/../../../arch/x86/include/uapi/asm/svm.h:249:11: note: in expansion of macro 'SVM_EXIT_ERR'
249 | { SVM_EXIT_ERR, "invalid_guest_state" }
| ^~~~~~~~~~~~
util/kvm-stat-arch/kvm-stat-x86.c:12:45: note: in expansion of macro 'SVM_EXIT_REASONS'
12 | define_exit_reasons_table(svm_exit_reasons, SVM_EXIT_REASONS);
| ^~~~~~~~~~~~~~~~
As the exit_code was unsigned long, the compiler complained about the
truncation. Let's convert it to u64 to suppress the error.
Fixes: fac520e43a ("tools headers: Sync KVM headers with the kernel sources")
Signed-off-by: Namhyung Kim <namhyung@kernel.org>
RISC-V post-link processing can remove relocation sections from the final
vmlinux while some .dynsym entries retain stale section indexes. perf
aborts the whole ELF symbol load when elf_getscn() rejects one of them,
discarding otherwise valid .symtab symbols.
Skip only dynamic symbols whose normal section index is outside the final
section table. Keep the existing error path for .symtab, reserved indexes,
and other libelf failures.
On an affected system, the vmlinux symtab matches kallsyms test changes
from Skip to Ok. [unknown] rows in the same perf.data change from 41 to 0.
Signed-off-by: Zhanpeng Zhang <zhangzhanpeng.jasper@bytedance.com>
Signed-off-by: Namhyung Kim <namhyung@kernel.org>
machines__create_guest_kernel_maps() builds the guest kallsyms path
with snprintf() without checking the return value. A truncated path
could pass the access() check if a prefix directory happens to contain
a file named "kallsyms", leading to the wrong file being used for
symbol resolution.
Check for truncation and skip the directory.
Fixes: a1645ce12a ("perf: 'perf kvm' tool for monitoring guest performance from host")
Reported-by: sashiko-bot <sashiko-bot@kernel.org>
Cc: Zhang, Yanmin <yanmin_zhang@linux.intel.com>
Assisted-by: Claude:claude-opus-4.6
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Signed-off-by: Namhyung Kim <namhyung@kernel.org>
machines__create_guest_kernel_maps() calls scandir() which allocates
both the namelist array and each individual dirent entry. The code
frees the namelist array but not the individual entries, leaking memory
proportional to the number of directories under guestmount.
Free each namelist[i] after it is no longer needed.
Fixes: a1645ce12a ("perf: 'perf kvm' tool for monitoring guest performance from host")
Reported-by: sashiko-bot <sashiko-bot@kernel.org>
Cc: Zhang, Yanmin <yanmin_zhang@linux.intel.com>
Assisted-by: Claude:claude-opus-4.6
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Signed-off-by: Namhyung Kim <namhyung@kernel.org>
machines__create_guest_kernel_maps() checks errno == ERANGE after
strtol() to detect overflow, but does not clear errno first. A stale
ERANGE from an earlier library call (e.g. scandir internals) causes
valid numeric directory names to be incorrectly skipped.
Set errno = 0 before strtol() so only the current conversion can
trigger the ERANGE check.
Fixes: a1645ce12a ("perf: 'perf kvm' tool for monitoring guest performance from host")
Reported-by: sashiko-bot <sashiko-bot@kernel.org>
Cc: Zhang, Yanmin <yanmin_zhang@linux.intel.com>
Assisted-by: Claude:claude-opus-4.6
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Signed-off-by: Namhyung Kim <namhyung@kernel.org>
machines__create_guest_kernel_maps() jumps to the failure label when one
guest directory's kallsyms file fails access(), skipping all remaining
valid guest directories. An inaccessible directory is not fatal — other
guests may still be reachable.
Replace 'goto failure' with 'continue' so the loop processes all
directories, and remove the now-unreferenced failure label.
Fixes: a1645ce12a ("perf: 'perf kvm' tool for monitoring guest performance from host")
Reported-by: sashiko-bot <sashiko-bot@kernel.org>
Cc: Zhang, Yanmin <yanmin_zhang@linux.intel.com>
Assisted-by: Claude:claude-opus-4.6
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Signed-off-by: Namhyung Kim <namhyung@kernel.org>
The guestmount path is built with snprintf() into a PATH_MAX buffer
without checking the return value. If symbol_conf.guestmount is long
enough to cause truncation, the truncated path could match a different
directory, causing the wrong guest to be associated with the pid.
Check for truncation and bail out early.
Fixes: a1645ce12a ("perf: 'perf kvm' tool for monitoring guest performance from host")
Reported-by: sashiko-bot <sashiko-bot@kernel.org>
Cc: Zhang, Yanmin <yanmin_zhang@linux.intel.com>
Assisted-by: Claude:claude-opus-4.6
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Signed-off-by: Namhyung Kim <namhyung@kernel.org>
The static 'seen' strlist caches guestmount paths that have already
been reported as inaccessible, to avoid repeating the error message.
If strlist__new() fails (OOM), 'seen' stays NULL and the next call
dereferences it via strlist__has_entry() and strlist__add().
Guard both calls so that on allocation failure the error message is
still printed (just not deduplicated) instead of crashing.
Fixes: c80c3c2690 ("perf kvm: Limit repetitive guestmount message to once per directory")
Reported-by: sashiko-bot <sashiko-bot@kernel.org>
Cc: David Ahern <dsahern@gmail.com>
Assisted-by: Claude:claude-opus-4.6
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Signed-off-by: Namhyung Kim <namhyung@kernel.org>
machine__process_fork_event() calls machine__findnew_thread() for the
parent thread, which can return NULL on allocation failure. The code
then dereferences parent via thread__pid(parent) without a NULL check
when validating whether the parent PID matches. The later NULL check
at thread__fork() does not prevent this earlier dereference.
Add a NULL guard before accessing the parent thread.
Fixes: 5cb73340d9 ("perf tools: Make fork event processing more resilient")
Reported-by: sashiko-bot <sashiko-bot@kernel.org>
Cc: Adrian Hunter <adrian.hunter@intel.com>
Assisted-by: Claude:claude-opus-4.6
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Signed-off-by: Namhyung Kim <namhyung@kernel.org>
The bounds check for root_len >= path_size returns -1 directly without
closing the directory fd opened by io_dir__init() a few lines above.
Jump to the out label instead, which calls close(iod.dirfd).
Fixes: e7af194681 ("perf machine: Reuse module path buffer")
Reported-by: sashiko-bot <sashiko-bot@kernel.org>
Cc: Ian Rogers <irogers@google.com>
Assisted-by: Claude:claude-opus-4.6
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Signed-off-by: Namhyung Kim <namhyung@kernel.org>
Fix spelling and abbreviation errors in the PTT packet decoder:
- HISI_PTT_FIELD_LENTH -> HISI_PTT_FIELD_LENGTH
- hisi_ptt_8dw_kpt_desc -> hisi_ptt_8dw_pkt_desc
- hisi_ptt_4dw_kpt_desc -> hisi_ptt_4dw_pkt_desc
Reviewed-by: James Clark <james.clark@linaro.org>
Signed-off-by: Sizhe Liu <liusizhe5@huawei.com>
Signed-off-by: Namhyung Kim <namhyung@kernel.org>
Fix pre-existing robustness issues in the hisi-ptt auxtrace decoder
reported by Sashiko:
1. Endianness in hisi_ptt_check_packet_type(): The first 32-bit word was
read with a host-endian memory cast (*(uint32_t *)buf). On big-endian
hosts analyzing a little-endian trace, the bit[31:11] 8DW magic check
fails and every 8DW packet is misclassified as 4DW. Read the header
with get_unaligned_le32().
2. Heap out-of-bounds read: hisi_ptt_dump() called
hisi_ptt_check_packet_type() which dereferenced 4 bytes of the buffer
without any size check. A malformed or truncated event with
auxtrace.size in {0,1,2,3} may cause a heap OOB read. Pass the buffer
length to hisi_ptt_check_packet_type() and return (defaulting to
4DW) when the buffer is shorter than HISI_PTT_FIELD_LENTH.
3. Integer truncation: event->auxtrace.size is __u64 but was stored in
an int. Traces larger than 2GB became negative (malloc failure), and
huge sizes wrapping to a small positive caused a short readn() that
left unread payload in the pipe and permanently desynchronized the
stream. Use u64 for the size, reject anything larger than SSIZE_MAX
before malloc (same bound used by auxtrace_copy_data()), and compare
readn()'s return value against (ssize_t)size to detect truncation.
Signed-off-by: Sizhe Liu <liusizhe5@huawei.com>
Signed-off-by: Namhyung Kim <namhyung@kernel.org>
TLP Headers traced by HiSilicon PCIe tune and trace device (PTT) in
4DW format are shown in the document as below:
bits [31:30] [ 29:25 ][24][23][22][21][ 20:11 ][ 10:0 ]
|-----|---------|---|---|---|---|-------------|-------------|
DW0 [ Fmt ][ Type ][T9][T8][TH][SO][ Length ][ Time ]
DW1 [ Header DW1 ]
DW2 [ Header DW2 ]
DW3 [ Header DW3 ]
Problem:
The DW0 bit field layout of the hisi_ptt_4dw union does not match the
actual bit ordering in little-endian memory, causing incorrect field
decoding.
Test on Kunpeng 930 SOC, generating data flow with `iperf` commands:
- server side:
iperf -s
- client side:
iperf -c $ip_addr -t 30
Trace the TLP headers with hisi_ptt on server side at the same time:
perf record -e hisi_ptt12_0/type=4,filter=0x05101,direction=2,format=0/ \
--max-size 50M -o perf.data &
The trace aims to capture completion TLPs, learn more in the document:
https://docs.kernel.org/trace/hisi-ptt.html
Decode perf.data with hisi_ptt decoder:
perf report -D
The hisi_ptt decoder produces the following result:
[...perf headers and other information]
. ... HISI PTT data: size 8388608 bytes
. 00000000: 68 87 20 94 Format 3 Type 1a T9 0 T8 1 TH 1 SO 1 Length 10 Time 4a1
. 00000004: 40 00 00 00 Header DW1
. 00000008: 40 00 01 51 Header DW2
. 0000000c: 00 00 00 00 Header DW3
[...other hisi_ptt TLP headers]
According to PCIe r5.0 sec 2.2.1, the Fmt & Type of Cpl/CplD is supposed
to be 8b'00001010' / 8b'01001010'
However, the Format & Type decoder analyzing result is 8b'01111010'.
It does not match field encodings of any TLP.
Correct decoder result should be:
[...perf headers and other information]
. ... HISI PTT data: size 8388608 bytes
. 00000000: 94 20 87 68 Format 2 Type a T9 0 T8 0 TH 0 SO 1 Length 10 Time 768
. 00000004: 00 00 00 40 Header DW1
. 00000008: 51 01 00 40 Header DW2
. 0000000c: 00 00 00 00 Header DW3
[...other hisi_ptt TLP headers]
To solve the problem:
1. Drop the union and C bitfield struct, store the raw DW value in
a plain uint32_t, and extract the fields with FIELD_GET() against
GENMASK/BIT masks declared in the header so they can be reused by
other translation units. The masks are portable across endianness and
compilers.
2. Print all DW hex values in big-endian byte order for readability,
matching the bit field layout shown in the 4DW format diagram.
3. Read the DW value with get_unaligned_le32() instead of an unaligned
pointer cast, avoiding both strict-aliasing violations and
alignment hazards on hosts that do not support unaligned access.
Cc: stable@vger.kernel.org
Fixes: 5e91e57e68 ("perf auxtrace arm64: Add support for parsing HiSilicon PCIe Trace packet")
Reviewed-by: James Clark <james.clark@linaro.org>
Signed-off-by: Sizhe Liu <liusizhe5@huawei.com>
Signed-off-by: Namhyung Kim <namhyung@kernel.org>
cu_walk_functions_at() calls libdw_a2l_cb() with the containing
DW_TAG_subprogram DIE first, then each DW_TAG_inlined_subroutine
nested inside. The callback treated both the same way, causing two
bugs:
1) die_name() returns the unqualified DW_AT_name, so every C++
frame lost its namespace/class prefix (ns::Class::method
collapsed to method).
2) new_inline_sym() re-uses base_sym only when funcname matches
base_sym->name exactly; otherwise it fabricates a fake symbol
tagged "(inlined)". Any mismatch between the DWARF name and
the ELF symbol name mis-tags an outer, non-inline frame as
inlined. This hits C++ (die_name()'s unqualified output never
matches the demangled ELF symbol) and it also hits C functions
that GCC IPA-cloned (foo vs foo.isra.0 / .constprop / .part /
.cold), since DW_AT_linkage_name doesn't reflect those renames.
Fix both:
* Prefer die_get_linkage_name() (mangled, fully qualified),
falling back to die_name() when absent (C, extern "C").
new_inline_sym() already demangles via dso__demangle_sym().
* For DW_TAG_subprogram DIEs, use base_sym directly -- the DIE
tag already tells us it is the outer function, sidestepping
the name comparison entirely for both C++ qualification and
GCC IPA-clone renames.
Fixes: 88c51002d0 ("perf addr2line: Add a libdw implementation")
Signed-off-by: Michael Liang <mliang@purestorage.com>
Reviewed-by: James Clark <james.clark@linaro.org>
Signed-off-by: Namhyung Kim <namhyung@kernel.org>
The libdw callback API has two levels: dwfl_getthread_frames() first finds
the requested thread using the next_thread() or get_thread() callback and
then walks its stack.
Since perf only has a snapshot of the stack of a single thread, it
provides a stubbed-out API that always returns the pid the Dwfl was
attached with (i.e. whatever was passed to dwfl_attach_state()), rather
than the actual sampled thread's TID.
Commit 6b2658b3f3 ("perf unwind-libdw: Don't discard loaded ELF/DWARF
after every unwind") changed libdw unwinding from recreating the Dwfl
object for each sample to caching it in struct maps, which is shared by
every thread in the process. It left next_thread() unchanged.
Since the pid passed to dwfl_attach_state() is only set at creation, only
the thread of the first sample is ever found. As a result,
dwfl_getthread_frames() fails with ESRCH when asked to unwind a sample
from another thread.
Make next_thread() return the current sample's TID, provide get_thread()
so libdw can find it directly, and pass the process PID expected by
dwfl_attach_state(). This allows libdw to unwind samples from every thread
in a multi-threaded process.
Add a shell regression test that records a four-thread workload and
verifies that libdw recovers the worker callchain for every worker TID.
Fixes: 6b2658b3f3 ("perf unwind-libdw: Don't discard loaded ELF/DWARF after every unwind")
Assisted-by: Codex:gpt-5.6-sol
Signed-off-by: Alessio Podda <aleph.pi.gh@gmail.com>
Signed-off-by: Namhyung Kim <namhyung@kernel.org>
- Update header copies of kernel headers, including const.h, fs.h,
perf_event.h, gfp_types.h, kvm.h, cpufeatures.h, rtnetlink.hp,
msr-index.h, drm.h and socket.h.
- Add some build files related to BPF skels to .gitignore.
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
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Merge tag 'perf-tools-fixes-for-v7.2-1-2026-07-25' into perf-tools-next
perf tools fixes for v7.2.
- Update header copies of kernel headers, including const.h, fs.h,
perf_event.h, gfp_types.h, kvm.h, cpufeatures.h, rtnetlink.hp,
msr-index.h, drm.h and socket.h.
- Add some build files related to BPF skels to .gitignore.
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Signed-off-by: Namhyung Kim <namhyung@kernel.org>
struct popup_action has a thread but this is duplicated in the
map_symbol. Remove the non-map_symbol version so that there's only ever
1 thread with a popup_action.
Assisted-by: Antigravity:gemini-3.5-flash
Signed-off-by: Ian Rogers <irogers@google.com>
Signed-off-by: Namhyung Kim <namhyung@kernel.org>
If a thread isn't given to map_symbol__get_arch(), try harder to determine
the arch for disassembly. Do this by utilizing fallback paths such as
reading the e_machine from a map's DSO ELF header for user-space libraries.
Additionally, rely on map__kmaps() and maps__machine() to reliably extract
the recorded machine environment and e_machine for kernel and kallsyms maps,
perfectly preventing silent, incorrect host fallbacks to uname() during
cross-platform Capstone annotation sessions.
At the same time, ensure all remaining uses of a map_symbol's thread pointer
do not assume it is non-NULL to eliminate UI segmentation faults, and remove
the fragile, redundant thread__get_arch() function to streamline the
annotate and disassembly subsystem architecture.
Fixes: 0e26ba5a87 ("perf disasm: Refactor arch__find and initialization of arch structs")
Assisted-by: Antigravity:gemini-3.5-flash
Signed-off-by: Ian Rogers <irogers@google.com>
Signed-off-by: Namhyung Kim <namhyung@kernel.org>
In hists_browser__zoom_map(), the active dso is assigned as a raw
pointer to hists->dso_filter without acquiring a reference using
dso__get(). This creates a potential use-after-free defect if the
underlying dso is released while the filter remains active.
Fix it by properly acquiring a reference via dso__get() when assigning
the filter, and releasing it with dso__put() when clearing it.
Additionally, since the browser stack relies on pstack__new() and deletes
it completely upon exiting, we must fully reset the persistent hists
structure by un-eliding columns and recalculating histogram filter
states for dso, thread, and symbols upon exit to guarantee immaculate,
uncorrupted state across browser tab switching.
Closes: https://lore.kernel.org/linux-perf-users/20260709170834.52F1A1F000E9@smtp.kernel.org/
Assisted-by: Antigravity:gemini-3.5-flash
Signed-off-by: Ian Rogers <irogers@google.com>
Signed-off-by: Namhyung Kim <namhyung@kernel.org>
Populates the map_symbol thread in the UI code to fix the e_machine
lookup for cross-platform disassembly when using the annotate action.
At the same time, refactor the UI options and actions generation to
comply with the perf subsystem's strict reference counting abstraction
requirements for 'struct map_symbol' and 'struct thread'. Introduce
explicit reference acquiring via map_symbol__copy() and thread__get() for
menu items, safely clean them up between menu iterations using a new
free_popup_actions() helper, and utilize insulated temporary action
variables for direct hotkey handler execution.
Fixes: 0e26ba5a87 ("perf disasm: Refactor arch__find and initialization of arch structs")
Reported-by: Josh Stone <jistone@redhat.com>
Assisted-by: Antigravity:gemini-3.5-flash
Signed-off-by: Ian Rogers <irogers@google.com>
Signed-off-by: Namhyung Kim <namhyung@kernel.org>
In add_script_opt(), when the browser selection has no valid hist_entry
(for example, when all entries are filtered out or the trace is empty),
hist_browser__selected_entry() returns NULL.
Add an explicit check for he == NULL prior to accessing he->time to avoid a
potential NULL pointer dereference crash.
Assisted-by: Antigravity:gemini-3.5-flash
Signed-off-by: Ian Rogers <irogers@google.com>
Signed-off-by: Namhyung Kim <namhyung@kernel.org>
In evsel__hists_browse(), the local stack array 'buf' is assigned
directly to the persistent 'hists->symbol_filter_str' pointer. When the
browser returns or is exited, this dangling pointer remains active in
the 'hists' struct and is read asynchronously by the perf top background
timer, triggering a stack use-after-return.
Fix it by properly duplicating the input string using strdup(), safely
invoking zfree() to prevent memory leaks when overwriting, and cleanly
resetting and freeing the symbol filter string upon exiting the browser.
Assisted-by: Antigravity:gemini-3.5-flash
Signed-off-by: Ian Rogers <irogers@google.com>
Signed-off-by: Namhyung Kim <namhyung@kernel.org>
Wire up the fchroot() system call as number 472 on (nearly) all
architectures and sync the mirrored copies of the syscall tables and
the asm-generic unistd.h under tools/.
Link: https://patch.msgid.link/20260724-work-failfs-v2-5-485dabbae185@kernel.org
Signed-off-by: Christian Brauner (Amutable) <brauner@kernel.org>
Try to remove some, but not all duplicate toolchain definitions. In
these instances, their makefiles already include
tools/scripts/Makefile.include which defines these in a consistent way.
STRIP is the only one that was set with an '=', but I don't think it
was significant so that difference can be dropped.
Signed-off-by: James Clark <james.clark@linaro.org>
Reviewed-by: Ian Rogers <irogers@google.com>
Acked-by: Ihor Solodrai <ihor.solodrai@linux.dev>
Acked-by: Kumar Kartikeya Dwivedi <memxor@gmail.com>
Signed-off-by: Namhyung Kim <namhyung@kernel.org>
Documentation/kbuild/llvm.rst mentions that readelf is included in the
LLVM toolchain, but it's not currently included in this block.
Add it so that LLVM=... options also apply to readelf. Users in tools/
were Perf which was hardcoding it, and another was the BPF makefile.
Both already include Makefile.include so convert them to use the new
variables.
Where readelf wasn't doing anything arch specific, use HOSTREADELF
because it's more likely to be installed.
Reviewed-by: Ian Rogers <irogers@google.com>
Signed-off-by: James Clark <james.clark@linaro.org>
Acked-by: Ihor Solodrai <ihor.solodrai@linux.dev>
Acked-by: Kumar Kartikeya Dwivedi <memxor@gmail.com>
Signed-off-by: Namhyung Kim <namhyung@kernel.org>
Provide a helper function trace__field_is_ip() in
trace__fprintf_tp_fields() to ensure that tracepoint fields representing
instruction pointers such as "__probe_ip", "caller_ip", and
"call_site" are always formatted as hexadecimal memory addresses rather
than signed integers.
For example, when running a kmem:kfree tracepoint:
# perf trace --show-cpu --event kmem:kfree --max-event 1
Before this change, "call_site" was represented as a signed integer:
0.000 [003] xfce4-terminal/2201 kmem:kfree(call_site: -1714572588, ptr: 0xffff8afee0303000)
After this change, "call_site" is correctly represented in hexadecimal:
0.000 [003] xfce4-terminal/2201 kmem:kfree(call_site: 0xffffffff99cf1194, ptr: 0xffff8afee0303000)
This improves the readability of perf trace output by making code
addresses straightforward to parse and map to kernel symbols.
Signed-off-by: Aaron Tomlin <atomlin@atomlin.com>
Signed-off-by: Namhyung Kim <namhyung@kernel.org>
Currently, dynamic non-array fields such as 'cpumask_t' are mishandled in
'perf trace', causing the raw length and offset descriptors to be interpreted
and displayed as a literal integer (e.g., "cpumask: 524320" instead of the
actual mask data).
Correct the parsing of dynamic fields that do not have the
TEP_FIELD_IS_ARRAY flag set by introducing helper functions
format_field__get_raw_data() and format_field__get_cpumask().
Using these helpers, resolve the pointer to the raw bits within the
payload and format the cpumask as a zero-padded hexadecimal string by default.
Fixes: c5e006cdbd ("perf trace: Support tracepoint dynamic char arrays")
Signed-off-by: Aaron Tomlin <atomlin@atomlin.com>
Signed-off-by: Namhyung Kim <namhyung@kernel.org>
Currently, jevents.py parses hundreds of JSON event and metric files
sequentially across all CPU architectures during Kbuild startup,
taking ~3.5 seconds of single-core execution time.
Refactor jevents.py to pre-populate its internal JSON AST cache in
parallel across all available CPU cores using
ProcessPoolExecutor. First gather all the paths with ftw and
collect_json, then spawn _parallel_read_json_events that starts
workers to just read the json events. Define the worker process
initializer _init_worker so that _arch_std_events is available under
spawn multiprocessing semantics.
This accelerates the JSON parsing phase by over 10x (from ~3.0s down
to ~290ms), reducing overall jevents.py execution time by 3.5x (from
~3.56s down to ~1.03s).
Tested-by: James Clark <james.clark@linaro.org>
Assisted-by: Gemini:gemini-3.1-pro-preview
Signed-off-by: Ian Rogers <irogers@google.com>
Signed-off-by: Namhyung Kim <namhyung@kernel.org>
Clean up and restructure the python setup script to resolve pylint
warnings, improve code quality, and increase robustness and
readability, targeting Python 3.9+ (the Linux kernel build minimum
Python version).
Changes:
- Restructure the script to use a `main()` function as the entry point,
leaving only imports, classes, and pure functions at module level.
- Eliminate all global/module-level variables, making them local to
`main()` or the respective classes/functions.
- Make `clang_has_option` a pure function by passing all necessary
parameters explicitly.
- Extract clang compiler flag filtering into a new
`filter_clang_options` helper function. This function uses a loop
over a tuple of options, replacing ~30 lines of repetitive blocks
and reducing branch/statement complexity in the main flow.
- Cleanly define attributes in `__init__` for `BuildExt` and
`InstallLib` and read environment variables dynamically within the
methods (including `srctree` in `InstallLib.run`), removing their
dependency on global variables.
- Replace legacy Popen with subprocess.run for safer process handling.
- Use quote-aware flag filtering (`shlex.split`, filter, `shlex.join`)
on sysconfig CFLAGS and OPT instead of regex `re.sub` substitutions.
This avoids boundary bugs and safely handles quoted arguments and
options with values.
- Rely on setuptools to handle user CFLAGS from the environment
directly rather than manually prepending them to extra_compile_args.
- Safely parse `CC` env var using `shlex.split` to handle quotes and
pass compiler arguments as `list[str]` lists to helper functions,
avoiding redundant string formatting and parsing.
- Remove unused `import re`.
- Rename setuptools command subclasses to PascalCase (BuildExt,
InstallLib).
- Add type annotations to functions and methods.
- Add missing docstrings for module, functions, and classes.
- Split long lines to adhere to standard limits.
Assisted-by: Antigravity:gemini-3.5-flash
Signed-off-by: Ian Rogers <irogers@google.com>
Signed-off-by: Namhyung Kim <namhyung@kernel.org>
Refactor perf_cap__capable() to completely remove the used_root out-parameter
as requested by the maintainer. Relying on an explicit used_root boolean
poisoned sequential capability checks (e.g. failing CAP_SYS_ADMIN checks
poisoning the flag for subsequent CAP_PERFMON evaluations for unprivileged
users) and created redundant complexity across check_ftrace_capable(),
symbol__read_kptr_restrict(), and perf_event_paranoid_check().
Streamline the capability API to perform a pure true/false boolean
evaluation. The function checks the Effective set using SYS_capget; if
the syscall is missing or fails on legacy kernels, it cleanly falls back
to checking EUID == 0. This perfectly preserves modern capability-aware host
sessions, guarantees transparent fallback for older kernels, and correctly
rejects privileged operations for containerized root processes that have
explicitly dropped their capability bounding and permitted sets.
Fixes: e25ebda78e ("perf cap: Tidy up and improve capability testing")
Suggested-by: Namhyung Kim <namhyung@kernel.org>
Assisted-by: Antigravity:gemini-3.5-flash
Signed-off-by: Ian Rogers <irogers@google.com>
Signed-off-by: Namhyung Kim <namhyung@kernel.org>
cs_etm__get_trace() returns an int, but it used to return etmq->buf_len
on success. That value comes from auxtrace_buffer::size, which is a
size_t. For a large AUX trace block, returning the byte count through an
int can overflow and make a valid buffer look like a negative error.
The callers do not need the actual byte count from cs_etm__get_trace().
The buffer length is already stored in the etmq->buf_len. The callers
only need to distinguish three states:
< 0: error
= 0: no more AUX buffers
> 0: data is available
Make cs_etm__get_trace() return 0 for all non-error cases and use
etmq->buf_len to indicate whether a new buffer was found. Then make
cs_etm__get_data_block() return 1 whenever data is available, instead of
returning the buffer length.
Also refactor cs_etm__get_data_block() to make its return value
semantics clearer.
Reported-by: Suyash Mahar <smahar@meta.com>
Fixes: 8224531cf5 ("perf cs-etm: Modularize auxtrace_buffer fetch function")
Signed-off-by: Leo Yan <leo.yan@arm.com>
Reviewed-by: James Clark <james.clark@linaro.org>
Signed-off-by: Namhyung Kim <namhyung@kernel.org>
To pick up the changes in:
45e57cfb7b ("fs: Clarify FS_CASEFOLD_FL semantics in UAPI header")
That don't result in changes to the string tables generated from this header.
This addresses this perf build warning:
Warning: Kernel ABI header differences:
diff -u tools/perf/trace/beauty/include/uapi/linux/fs.h include/uapi/linux/fs.h
Please see tools/include/uapi/README for further details.
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
To pick up the changes in:
4987a5763f ("net: block MSG_NO_SHARED_FRAGS in sendmsg()")
That don't result in changes to the string tables generated from this header.
This addresses this perf build warning:
Warning: Kernel ABI header differences:
diff -u tools/perf/trace/beauty/include/linux/socket.h include/linux/socket.h
Please see tools/include/uapi/README for further details.
Cc: Jann Horn <jannh@google.com>
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
To pick up the changes in:
a1b6cf8e5e ("drm: uapi: Use SPDX in DRM core uAPI headers")
dc2d30e7db ("drm/doc: document DRM_IOCTL_SYNCOBJ_EVENTFD")
That don't result in changes to the string tables generated from this header.
This addresses this perf build warning:
Warning: Kernel ABI header differences:
diff -u tools/perf/trace/beauty/include/uapi/drm/drm.h include/uapi/drm/drm.h
Please see tools/include/uapi/README for further details.
Cc: Laurent Pinchart <laurent.pinchart+renesas@ideasonboard.com>
Cc: Simon Ser <contact@emersion.fr>
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
In 713eeb2279 ("perf build: Move BPF skeleton generation out of
Makefile.perf") the bpf_skel used with 'perf bench uprobe' was moved
from tools/perf/util/bpf_skel/ to tools/perf/bench/bpf_skel.
Copy tools/perf/util/bpf_skel/.gitignore to that new directory so that
files generated during build get ignored by git.
Reported-by: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Adrian Hunter <adrian.hunter@intel.com>
Cc: Ian Rogers <irogers@google.com>
Cc: James Clark <james.clark@linaro.org>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: Namhyung Kim <namhyung@kernel.org>
Fixes: 713eeb2279 ("perf build: Move BPF skeleton generation out of Makefile.perf")
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
When monitoring a large number of events (e.g., with wildcards such as
--event 'syscalls:sys_enter_*'), many matched events will return a count
of zero. This clutters the output, making it difficult to spot the
active events.
Add a new option --hide-zero-events to suppress printing events that
have a count of zero.
To prevent formatting and diagnostic issues, the zero-skipping logic
implements the following rules:
1. In metric-only mode (i.e., --metric-only), columns must remain
aligned in the output grid. We evaluate config->metric_only first
to avoid skipping zero-valued columns, preventing values from
shifting left and aligning under incorrect headers
2. For explicitly requested events, we ensure they are not silently
hidden if they are unsupported. We only hide a zero-count event
if counter->supported is true, ensuring that unsupported explicit
events still report "<not supported>"
Signed-off-by: Aaron Tomlin <atomlin@atomlin.com>
Reviewed-by: Ian Rogers <irogers@google.com>
Signed-off-by: Namhyung Kim <namhyung@kernel.org>
It seems RISCV was added in capstone version 5 (released Jul 2023).
Unfortunately they are enum constants so cannot check with #ifdef but
anyway we can define the symbols. Let's do it using the version
number to avoid build errors. It'll fail at runtime though.
util/capstone.c: In function 'e_machine_to_capstone':
util/capstone.c:186:25: error: 'CS_ARCH_RISCV' undeclared (first use in this function);
did you mean 'CS_ARCH_SYSZ'?
186 | *arch = CS_ARCH_RISCV;
| ^~~~~~~~~~~~~
| CS_ARCH_SYSZ
util/capstone.c:186:25: note: each undeclared identifier is reported only once for each function it appears in
util/capstone.c:187:34: error: 'CS_MODE_RISCV64' undeclared (first use in this function);
did you mean 'CS_MODE_MIPS64'?
187 | *mode |= (is64 ? CS_MODE_RISCV64 : CS_MODE_RISCV32) | CS_MODE_RISCVC;
| ^~~~~~~~~~~~~~~
| CS_MODE_MIPS64
Also note that capstone renamed CS_MODE_RISCVC to CS_MODE_RISCV_C which
would cause a different build failure on latest versions. It's reported
in https://github.com/capstone-engine/capstone/issues/2977 so I think
they will add compatibility layer to prevent the error.
Fixes: 12c4737f55 ("perf capstone: Determine architecture from e_machine")
Signed-off-by: Namhyung Kim <namhyung@kernel.org>
In add_script_opt(), the function unconditionally increments the optstr
and act pointers for a second optional 'time' popup action before
attempting to invoke add_script_opt_2(). If the first add_script_opt_2()
call failed (for example, due to an asprintf allocation failure), this
leaves a NULL pointer gap in the options array at the prior index. When
ui__popup_menu() is later displayed, it dereferences this gap and
crashes.
Fix it by avoiding unconditional pointer increments. Only advance the
optstr and act pointers if the first script addition actually succeeded,
and safely attach the time parameter to the correct assigned action.
Assisted-by: Antigravity:gemini-3.5-flash
Signed-off-by: Ian Rogers <irogers@google.com>
Signed-off-by: Namhyung Kim <namhyung@kernel.org>
In arch__find(), if the architecture's arch_new_fn[e_machine]() returns
NULL, the error handling path attempts to read result->name, dereferencing
a NULL pointer and crashing. At the same time, it invokes free(tmp)
BEFORE updating the static global archs pointer to tmp. If the
reallocarray() call moved the allocated block, the original archs pointer
remained active but was freed. A subsequent call to arch__find() would
then pass this dangling pointer into bsearch(), causing a use-after-free.
Fix both by printing the numeric e_machine ID instead of result->name,
and updating the static global archs pointer to tmp immediately after the
successful reallocarray() invocation to safely retain the valid prior
architectures.
Closes: https://lore.kernel.org/linux-perf-users/20260709035721.9EE901F000E9@smtp.kernel.org/
Assisted-by: Antigravity:gemini-3.5-flash
Signed-off-by: Ian Rogers <irogers@google.com>
Signed-off-by: Namhyung Kim <namhyung@kernel.org>
Looking at switch_data_file(), it uses the POSIX constant PATH_MAX.
Omitting the explicit inclusion of limits.h can cause build failures on
musl libc systems, which do not implicitly include headers in the same way
glibc does. Fix this by explicitly including <limits.h> at the top of
tools/perf/ui/browsers/hists.c.
Assisted-by: Antigravity:gemini-3.5-flash
Signed-off-by: Ian Rogers <irogers@google.com>
Signed-off-by: Namhyung Kim <namhyung@kernel.org>
In evsel__hists_browse(), the 'options' and 'actions' arrays are
statically allocated on the stack with a size of MAX_OPTIONS (16).
Further down, the function sequentially calls several add_*_opt()
functions, which increment nr_options without bounds checking.
Depending on the context (e.g., branch mode, scripting, annotations),
the sum of added options can theoretically exceed 16 (potentially
reaching up to ~19). This could lead to a stack buffer overflow.
Increase MAX_OPTIONS to 32 to safely accommodate the maximum possible
number of options without risking an overflow.
Closes: https://lore.kernel.org/linux-perf-users/20260708235834.3FB771F00A3A@smtp.kernel.org/
Assisted-by: Antigravity:gemini-3.5-flash
Signed-off-by: Ian Rogers <irogers@google.com>
Link: https://lore.kernel.org/linux-perf-users/20260708235834.3FB771F00A3A@smtp.kernel.org/
Signed-off-by: Namhyung Kim <namhyung@kernel.org>
The bfd_boolean type was gone and converted to the standard bool type
but we have some old code that uses the type. It caused a failure in
the build test.
util/libbfd.c: In function 'slurp_symtab':
util/libbfd.c:94:9: error: unknown type name 'bfd_boolean'
94 | bfd_boolean dynamic = FALSE;
| ^~~~~~~~~~~
util/libbfd.c:94:31: error: 'FALSE' undeclared (first use in this function)
94 | bfd_boolean dynamic = FALSE;
| ^~~~~
util/libbfd.c:94:31: note: each undeclared identifier is reported only once for each function it appears in
util/libbfd.c:102:27: error: 'TRUE' undeclared (first use in this function)
102 | dynamic = TRUE;
| ^~~~
Fix it with standard bool type and constants.
Reviewed-by: Ian Rogers <irogers@google.com>
Link: https://sourceware.org/pipermail/binutils-cvs/2021-March/056231.html
Signed-off-by: Namhyung Kim <namhyung@kernel.org>
The loop for processing syscall args in augment_raw_syscalls has a
history of breaking with Clang updates, see e.g. commit 013eb043f3
("perf trace: Fix BPF loading failure (-E2BIG)") from Clang 15 to 16.
Now, a similar thing happened between Clang 21 and 22. While the issue
is mitigated on the main line by a recent verifier update, it remains
broken on the 6.12 and 6.18 stable branches:
[linux-6.18.y]# sudo perf trace true
libbpf: prog 'sys_enter': BPF program load failed: -E2BIG
libbpf: prog 'sys_enter': -- BEGIN PROG LOAD LOG --
[...]
BPF program is too large. Processed 1000001 insn
processed 1000001 insns (limit 1000000) max_states_per_insn 40 total_states 37941 peak_states 232 mark_read 0
-- END PROG LOAD LOG --
libbpf: prog 'sys_enter': failed to load: -E2BIG
libbpf: failed to load object 'augmented_raw_syscalls_bpf'
libbpf: failed to load BPF skeleton 'augmented_raw_syscalls_bpf': -E2BIG
Error: failed to get syscall or beauty map fd
[...]
The reason is that the loop is quite complex and the BPF verifier often
struggles to prove that it terminates.
Fix the issue by replacing the standard for loop with the bpf_for macro,
which uses a numeric BPF iterator. This should prevent future breakages
of this kind since the verifier has a much easier job proving that the
loop terminates.
Small adjustments were necessary for the loop to make it work. The main
problem is that the verifier sometimes has problems with bpf_for loops
that use a carry-over state, such as the `payload_offset` and `output`
vars here, since the verifier tries to track their values too precisely
and cannot prove loop convergence. To resolve the issue, we (1)
explicitly recompute `payload_offset` in every iteration and (2) use a
trick with adding a global zero to `output` to help the verifier forget
its precise state and use a range instead.
Finally, to keep backwards compatibility with older kernel versions that
don't have bpf_for (i.e. numeric iterators), fall back to standard loop.
Signed-off-by: Viktor Malik <vmalik@redhat.com>
Cc: stable@vger.kernel.org
Suggested-by: Andrii Nakryiko <andrii@kernel.org>
Fixes: a68fd6a6cd ("perf trace: Collect augmented data using BPF")
Signed-off-by: Namhyung Kim <namhyung@kernel.org>
The BPF program in augmented_raw_syscalls uses a for loop to iterate all
syscall arguments. The loop body is quite complex and often poses
problems for the BPF verifier. As a preparation step for addressing this
issue, factor out the loop body into a separate function.
Signed-off-by: Viktor Malik <vmalik@redhat.com>
Cc: stable@vger.kernel.org
Signed-off-by: Namhyung Kim <namhyung@kernel.org>
To simply check the number of output lines with and without the option.
Before this series, it failed like below:
$ perf test -v 125
125: perf stat --bpf-counters --for-each-cgroup test:
---- start ----
test child forked, pid 1941516
Normal output has 22 lines, but it now has 54
---- end(-1) ----
125: perf stat --bpf-counters --for-each-cgroup test : FAILED!
Signed-off-by: Namhyung Kim <namhyung@kernel.org>
In the evsel, there's an internal struct to put fields need copy when
the evsel is cloned. This is purely to make it easier track those
fields even if it sometimes failed to do so. :)
Signed-off-by: Namhyung Kim <namhyung@kernel.org>
IIUC bpf_fd and bpf_obj fields are not used anymore. It seems like
leftover from 3d6dfae889 ("perf parse-events: Remove BPF event
support").
Signed-off-by: Namhyung Kim <namhyung@kernel.org>
The --bpf-counters and --for-each-cgroup options use a set of shared
events among the given cgroups rather than adding events for each cgroup
respectively. It only uses cgroup-ID to compare and calculate the
result. So no need to open and keep FDs for cgroups in BPF mode.
Signed-off-by: Namhyung Kim <namhyung@kernel.org>
Nazar Kazakov reported non-deterministic builds due to the metrics
being reordered in the jevents.py output. The metrics were largely
only being sorted by name, add in the expressions and descriptions.
Reported-by: Nazar Kazakov <nazar.kazakov@codethink.co.uk>
Closes: https://lore.kernel.org/linux-perf-users/20260706175624.692736-1-nazar.kazakov@codethink.co.uk/
Fixes: 40769665b6 ("perf jevents: Parse metrics during conversion")
Tested-by: Nazar Kazakov <nazar.kazakov@codethink.co.uk>
Signed-off-by: Ian Rogers <irogers@google.com>
Signed-off-by: Namhyung Kim <namhyung@kernel.org>
The first entry of the sched_usage is dynamically allocated in
parse_options_subcommand() so it should be released at the end.
Do not return from a subcommand directly.
Fixes: 064790a3d4 ("perf sched stats: Add support for diff subcommand")
Reviewed-and-tested-by: Swapnil Sapkal <swapnil.sapkal@amd.com>
Signed-off-by: Namhyung Kim <namhyung@kernel.org>
The second pass data is not saved in the list and only used to calculate
delta from the first pass. Let's free the data after use.
Fixes: 5a357ae6ad ("perf sched stats: Add support for report subcommand")
Reviewed-and-tested-by: Swapnil Sapkal <swapnil.sapkal@amd.com>
Signed-off-by: Namhyung Kim <namhyung@kernel.org>
The perf sched stats record missed to release the session and ASAN
reported a leak.
Fixes: c3030995f2 ("perf sched stats: Add record and rawdump support")
Reviewed-and-tested-by: Swapnil Sapkal <swapnil.sapkal@amd.com>
Signed-off-by: Namhyung Kim <namhyung@kernel.org>
The updated events were published in:
240735b7d8
Signed-off-by: Chun-Tse Shao <ctshao@google.com>
Reviewed-by: Dapeng Mi <dapeng1.mi@linux.intel.com>
Signed-off-by: Namhyung Kim <namhyung@kernel.org>
The updated events were published in:
d1bc6c1e8b
Signed-off-by: Chun-Tse Shao <ctshao@google.com>
Reviewed-by: Dapeng Mi <dapeng1.mi@linux.intel.com>
Signed-off-by: Namhyung Kim <namhyung@kernel.org>
The updated events were published in:
ce70546e9c
Signed-off-by: Chun-Tse Shao <ctshao@google.com>
Reviewed-by: Dapeng Mi <dapeng1.mi@linux.intel.com>
Signed-off-by: Namhyung Kim <namhyung@kernel.org>
The updated events were published in:
3aa49b0634
Signed-off-by: Chun-Tse Shao <ctshao@google.com>
Reviewed-by: Dapeng Mi <dapeng1.mi@linux.intel.com>
Signed-off-by: Namhyung Kim <namhyung@kernel.org>
The updated events were published in:
704ef43e4c
Signed-off-by: Chun-Tse Shao <ctshao@google.com>
Reviewed-by: Dapeng Mi <dapeng1.mi@linux.intel.com>
Signed-off-by: Namhyung Kim <namhyung@kernel.org>
The updated events were published in:
2ba9dec72a
Signed-off-by: Chun-Tse Shao <ctshao@google.com>
Reviewed-by: Dapeng Mi <dapeng1.mi@linux.intel.com>
Signed-off-by: Namhyung Kim <namhyung@kernel.org>
The updated events were published in:
084ecb869d
Signed-off-by: Chun-Tse Shao <ctshao@google.com>
Reviewed-by: Dapeng Mi <dapeng1.mi@linux.intel.com>
Signed-off-by: Namhyung Kim <namhyung@kernel.org>
The updated events were published in:
e479bd6768
Signed-off-by: Chun-Tse Shao <ctshao@google.com>
Reviewed-by: Dapeng Mi <dapeng1.mi@linux.intel.com>
Signed-off-by: Namhyung Kim <namhyung@kernel.org>
The updated events were published in:
13983cd535
Signed-off-by: Chun-Tse Shao <ctshao@google.com>
Reviewed-by: Dapeng Mi <dapeng1.mi@linux.intel.com>
Signed-off-by: Namhyung Kim <namhyung@kernel.org>
The updated events were published in:
b23ebe7bc2
Signed-off-by: Chun-Tse Shao <ctshao@google.com>
Reviewed-by: Dapeng Mi <dapeng1.mi@linux.intel.com>
Signed-off-by: Namhyung Kim <namhyung@kernel.org>
The updated events were published in:
7a14cc8fea
Signed-off-by: Chun-Tse Shao <ctshao@google.com>
Reviewed-by: Dapeng Mi <dapeng1.mi@linux.intel.com>
Signed-off-by: Namhyung Kim <namhyung@kernel.org>
The updated events were published in:
7a14cc8fea
Signed-off-by: Chun-Tse Shao <ctshao@google.com>
Reviewed-by: Dapeng Mi <dapeng1.mi@linux.intel.com>
Signed-off-by: Namhyung Kim <namhyung@kernel.org>
In evsel__tp_format(), when trace_event__tp_format*() returns an error,
IS_ERR() checks the local variable 'tp_format', but PTR_ERR() incorrectly
uses 'evsel->tp_format' which hasn't been assigned yet.
Fix this by using PTR_ERR(tp_format) to extract the error code from the
correct variable.
Fixes: 6c8310e838 ("perf evsel: Allow evsel__newtp without libtraceevent")
Signed-off-by: Hongling Zeng <zenghongling@kylinos.cn>
Signed-off-by: Namhyung Kim <namhyung@kernel.org>
Use MAP_FAILED instead of NULL to detect mmap errors, and fix the
slots_p variable name typo in the sample code.
Signed-off-by: Hongfu Li <lihongfu@kylinos.cn>
Signed-off-by: Namhyung Kim <namhyung@kernel.org>
New OMR MSRs are introduced for OMR events on DMR and NVL. Perf continues
to reuse the existing offcore_rsp attribute to encode the MSR value,
similar to existing OCR event handling.
Add the corresponding OMR MSR mappings in lookup_msr() so jevents can
translate these events and generate the correct offcore_rsp attribute.
Link: https://lore.kernel.org/all/20260114011750.350569-2-dapeng1.mi@linux.intel.com/
Signed-off-by: Dapeng Mi <dapeng1.mi@linux.intel.com>
Signed-off-by: Namhyung Kim <namhyung@kernel.org>
Remove duplicate inclusion of util/term.h in builtin-test.c to clean up
redundant code.
Signed-off-by: Chen Ni <nichen@iscas.ac.cn>
Reviewed-by: Ian Rogers <irogers@google.com>
Signed-off-by: Namhyung Kim <namhyung@kernel.org>
With Zstd compression enabled ('perf record -z'), a single mmap push
whose compressed output exceeds the maximum record size makes
zstd_compress_stream_to_records() emit several PERF_RECORD_COMPRESSED2
records back to back. record__pushfn() however rewrote only the first
record's header to describe the whole blob as one record:
event->data_size = compressed - sizeof(struct perf_record_compressed2);
event->header.size = PERF_ALIGN(compressed, sizeof(u64));
padding = event->header.size - compressed;
...
record__write(rec, map, &pad, padding);
perf_event_header::size is a __u16, so once the compressed blob no
longer fits in it the header.size assignment truncates and 'padding'
(size_t) underflows. write() is then handed that bogus length and fails
with EFAULT, aborting the recording:
failed to write perf data, error: Bad address
The bytes that did reach the file are mis-framed, so reading it back
cannot be decompressed.
This is easy to hit with a high event rate and a large buffer, e.g.:
perf record -z -F max -m 32M --per-thread -- perf test -w thloop 5 1
The single-record fixup is wrong by construction: because header.size is
16 bits a compressed record cannot exceed 64KB, so the compressor must
split a push into a chain of records, and the session reader already
consumes them as such.
Frame each record where it is produced instead: make
process_comp_header() set the per-record data_size, 8-byte-align
header.size and zero the trailing padding, and let record__pushfn()
write the resulting blob, as the AIO path already does. Reduce
max_record_size by sizeof(u64) so the per-record alignment padding
cannot push header.size past its u16 field. process_comp_header()
returns -1 when that padding would not fit the space left in 'dst', so
the compressor stops instead of overrunning the output buffer.
There is no on-disk format change; a perf.data written by the fixed tool
is still read by existing perf.
Fixes: 208c0e1683 ("perf record: Add 8-byte aligned event type PERF_RECORD_COMPRESSED2")
Reported-by: Farid Zakaria <fmzakari@meta.com>
Signed-off-by: Dmitry Ilvokhin <d@ilvokhin.com>
Signed-off-by: Namhyung Kim <namhyung@kernel.org>
process_comp_header() is called from zstd_compress_stream_to_records()
twice per record: once with data_size == 0 to write the record header,
and once with the payload size to finalize it. It returns the increment
it was passed, and the loop separately decides whether a record still
fits by comparing the remaining 'dst_size' against the header size.
With the fit check split from the code that writes the record,
process_comp_header() cannot reject a record on its own, so any bytes it
writes into 'dst' have to be bounds-checked by the caller instead of
where they are produced.
Pass the space left in 'dst' to process_comp_header(), let it return the
number of bytes written or -1 when the header does not fit, and account
the compressed payload in the loop.
No functional change intended.
Signed-off-by: Dmitry Ilvokhin <d@ilvokhin.com>
Signed-off-by: Namhyung Kim <namhyung@kernel.org>
