linux-stable.git/tools/perf, branch v6.18.41

perf callchain: Handle multiple address spaces

2026-07-24T14:17:26+00:00

commit ae15db3e9b639491007cc1e9e99638e4b6091781 upstream.

perf test 'perf inject to convert DWARF callchains to regular ones'
fails on s390. It was introduced with commit 92ea788d2af4e65a ("perf
inject: Add --convert-callchain option")

The failure comes the difference in output. Without the inject script to
convert DWARF the callchains is:

 # perf record -F 999 --call-graph dwarf -- perf test -w noploop
 # perf report -i perf.data --stdio --no-children -q \
					 --percent-limit=1 > /tmp/111
 # cat /tmp/111
    99.30%  perf-noploop  perf               [.] noploop
            |
            ---noploop
               run_workload (inlined)
               cmd_test
               run_builtin (inlined)
               handle_internal_command
               run_argv (inlined)
               main
               __libc_start_call_main
               __libc_start_main_impl (inlined)
               _start
 #

With the inject script step the output is:

 # perf inject -i perf.data --convert-callchain -o /tmp/perf-inject-1.out
 # perf report -i /tmp/perf-inject-1.out --stdio --no-children -q \
		--percent-limit=1 > /tmp/222
 # cat /tmp/222
    99.40%  perf-noploop  perf               [.] noploop
            |
            ---noploop
               run_workload (inlined)
               cmd_test
               run_builtin (inlined)
               handle_internal_command
               run_argv (inlined)
               main
               _start
 # diff /tmp/111 /tmp/222
 1c1
 <     99.30%  perf-noploop  perf               [.] noploop
 ---
 >     99.40%  perf-noploop  perf               [.] noploop
 10,11d9
 <                __libc_start_call_main
 <                __libc_start_main_impl (inlined)
 #

The difference are the symbols __libc_start_call_main and
__libc_start_main_impl.

On x86_64, kernel and user space share a single virtual address space,
with the kernel mapped to the upper end of memory. The instruction
pointer value alone is sufficient to distinguish between user space and
kernel space addresses.

This is not true for s390, which uses separate address spaces for user
and kernel.

The same virtual address can be valid in both address spaces, so the
instruction pointer value alone cannot determine whether an address
belongs to the kernel or user space.

Instead, perf must rely on the cpumode metadata derived from the
processor status word (PSW) at sample time.

In function perf_event__convert_sample_callchain() the first part
copies a kernel callchain and context entries, if any.

It then appends additional entries ignoring the address space
architecture. Taking that into account, the symbols at addresses

   0x3ff970348cb __libc_start_call_main
   0x3ff970349c5 __libc_start_main_impl

(located after the kernel address space on s390) are now included.

Output before:

 # perf test 83
 83: perf inject to convert DWARF callchains to regular ones : FAILED!

Output after:
 # perf test 83
 83: perf inject to convert DWARF callchains to regular ones : Ok

Question to Namhyung:

In function perf_event__convert_sample_callchain() just before the
for() loop this patch modifies, the kernel callchain is copied,
see this comment and the next 5 lines:

   /* copy kernel callchain and context entries */

Then why is machine__kernel_ip() needed in the for() loop, when
the kernel entries have been copied just before the loop?

Note: This patch was tested on x86_64 virtual machine and succeeded.

Fixes: 92ea788d2af4e65a ("perf inject: Add --convert-callchain option")
Signed-off-by: Thomas Richter 
Acked-by: Namhyung Kim 
Cc: Alexander Gordeev 
Cc: Heiko Carstens 
Cc: Jan Polensky 
Cc: linux-s390@vger.kernel.org
Cc: Sumanth Korikkar 
Cc: Vasily Gorbik 
Signed-off-by: Arnaldo Carvalho de Melo 
Signed-off-by: Greg Kroah-Hartman

perf inject: With --convert-callchain ignore the dummy event for dwarf stacks

2026-07-24T14:17:26+00:00

commit e786a04b4a5461dd7e2829422314a5a6d5a664d9 upstream.

On hybrid systems there is generally >1 event and a dummy event.

The perf inject --convert-callchain option is failing to convert
perf.data files on such systems reporting "--convert-callchain requires
DWARF call graph."

The failing event is the dummy event that doesn't need to be set up for
samples.

As such ignore this event when checking the evsels.

Fixes: 92ea788d2af4e65a ("perf inject: Add --convert-callchain option")
Signed-off-by: Ian Rogers 
Tested-by: Arnaldo Carvalho de Melo 
Cc: Adrian Hunter 
Cc: Alexander Shishkin 
Cc: Ingo Molnar 
Cc: James Clark 
Cc: Jiri Olsa 
Cc: Namhyung Kim 
Cc: Peter Zijlstra 
Signed-off-by: Arnaldo Carvalho de Melo 
Signed-off-by: Greg Kroah-Hartman

perf symbol: Fix ENOENT case for filename__read_build_id

2026-07-24T14:17:26+00:00

commit 5c5f6fe32df2edb4f72bdca62ec2b9f20b7c5ba4 upstream.

Some callers of filename__read_build_id assume the error value must be
-1, fix by making them handle all < 0 values.

If is_regular_file fails in filename__read_build_id then it could be
the file is missing (ENOENT) and it would be wrong to return
-EWOULDBLOCK in that case. Fix the logic so -EWOULDBLOCK is only
reported if other errors with stat haven't occurred.

Fixes: 834ebb5678d7 ("perf tools: Don't read build-ids from non-regular files")
Signed-off-by: Ian Rogers 
Reviewed-by: James Clark 
Signed-off-by: Namhyung Kim 
Signed-off-by: Greg Kroah-Hartman

perf dso: Set standard errno on decompression failure

2026-07-24T14:16:30+00:00

[ Upstream commit 1a5f9334a45a6b0c1cd7341cc72a3b87adad1d27 ]

dso__get_filename() sets errno to a negative custom DSO_LOAD_ERRNO
value when kernel module decompression fails:

  errno = *dso__load_errno(dso);  /* e.g. -9996 */

The caller __open_dso() then computes fd = -errno, producing a large
positive value (9996) that looks like a valid file descriptor.  This
can cause close_data_fd() to close an unrelated fd used by another
subsystem.

Set errno to EIO instead.  The detailed error code is already stored
in dso__load_errno(dso) for diagnostic messages.

Fixes: 1d6b3c9ba756a513 ("perf tools: Decompress kernel module when reading DSO data")
Reported-by: sashiko-bot 
Cc: Namhyung Kim 
Assisted-by: Claude:claude-opus-4.6
Signed-off-by: Arnaldo Carvalho de Melo 
Signed-off-by: Sasha Levin

perf bpf: Validate array presence before casting BPF prog info pointers

2026-07-24T14:16:29+00:00

[ Upstream commit 5ebf4137d23a4fd6c0cc6a6fb766ee60d2b09193 ]

Several functions cast bpf_prog_info fields (jited_ksyms,
jited_func_lens, jited_prog_insns) from u64 to pointers and
dereference them.  These fields are only valid pointers if
bpil_offs_to_addr() converted their file offsets to addresses, which
only happens when the corresponding PERF_BPIL_* bits are set in
info_linear->arrays.

A crafted perf.data can leave these bits unset while setting non-zero
counts and offset values, causing the functions to dereference raw file
offsets as pointers.

Add array bitmask validation to all perf.data processing paths:

  - __bpf_event__print_bpf_prog_info(): check JITED_KSYMS and
    JITED_FUNC_LENS (changed to take struct perf_bpil *)
  - machine__process_bpf_event_load(): check JITED_KSYMS
  - bpf_read(): check JITED_INSNS before memcpy from jited_prog_insns
  - dso__disassemble_filename(): check JITED_INSNS before returning
    jited_prog_insns pointer

Fixes: f8dfeae009effc0b ("perf bpf: Show more BPF program info in print_bpf_prog_info()")
Reported-by: sashiko-bot 
Cc: Song Liu 
Assisted-by: Claude:claude-opus-4.6
Signed-off-by: Arnaldo Carvalho de Melo 
Signed-off-by: Sasha Levin

perf cs-etm: Bounds-check CPU in cs_etm__get_queue()

2026-07-24T14:16:29+00:00

[ Upstream commit 9a989e60cc6e29d98aed2087425cba53bf4b392d ]

cs_etm__get_queue() indexes etm->queues.queue_array[cpu] without
validating that cpu is within nr_queues.  When processing
AUX_OUTPUT_HW_ID events, the cpu value comes from untrusted perf.data
trace payload and flows through cs_etm__process_trace_id_v0_1() and
cs_etm__queue_aux_fragment() without bounds checking, allowing an
out-of-bounds read with a crafted file.

Add a bounds check in cs_etm__get_queue() and NULL checks in all
callers.

Also add NULL checks for queue_array[i].priv in the queue iteration
loops in cs_etm__map_trace_id_v0() and cs_etm__process_trace_id_v0_1()
— after auxtrace_queues__grow() new entries are zero-initialized so
.priv can be NULL.  Add a get_cpu_data() NULL check in
cs_etm__process_trace_id_v0_1(), matching the existing check in
cs_etm__process_trace_id_v0().

Fixes: 77c123f53e97ad4b ("perf: cs-etm: Move traceid_list to each queue")
Reported-by: sashiko-bot 
Cc: Adrian Hunter 
Cc: James Clark 
Cc: Leo Yan 
Assisted-by: Claude:claude-opus-4.6
Signed-off-by: Arnaldo Carvalho de Melo 
Signed-off-by: Sasha Levin

perf cs-etm: Require full global header in auxtrace_info size check

2026-07-24T14:16:29+00:00

[ Upstream commit 78d8ba680126f3545e8d0fba667e12d79fd4353b ]

cs_etm__process_auxtrace_info() checks that header.size covers
event_header_size + INFO_HEADER_SIZE (16 bytes total), but then
accesses ptr[CS_PMU_TYPE_CPUS] at offset 24 from the start of the
event.  A crafted 16-byte auxtrace_info event passes the size check
but reads out-of-bounds.

Include CS_ETM_HEADER_SIZE in the minimum size check so that the
global header entries (version, pmu_type_cpus, snapshot) are
guaranteed to fit within the event.

Fixes: 55c1de9973d66516 ("perf cs-etm: Print auxtrace info even if OpenCSD isn't linked")
Reported-by: sashiko-bot 
Cc: Adrian Hunter 
Cc: James Clark 
Cc: Leo Yan 
Assisted-by: Claude:claude-opus-4.6
Signed-off-by: Arnaldo Carvalho de Melo 
Signed-off-by: Sasha Levin

perf cs-etm: Validate num_cpu before metadata allocation

2026-07-24T14:16:29+00:00

[ Upstream commit 312d91329b8fc6989a916a3f9a12d0674167b7e4 ]

cs_etm__process_auxtrace_info_full() reads num_cpu from untrusted
perf.data and uses it to allocate the metadata pointer array:

  metadata = zalloc(sizeof(*metadata) * num_cpu);

On 32-bit, sizeof(*metadata) is 4, so num_cpu = 0x40000000 overflows
the multiplication to 0, causing zalloc(0) to return a valid zero-sized
allocation followed by out-of-bounds writes in the population loop.

Fix by computing priv_size early and using it to bound num_cpu: each
CPU needs at least one u64 metadata entry, so num_cpu cannot exceed
the total number of u64 entries in the event's private data area.

Fixes: cd8bfd8c973eaff8 ("perf tools: Add processing of coresight metadata")
Reported-by: sashiko-bot 
Cc: Adrian Hunter 
Cc: James Clark 
Cc: Leo Yan 
Cc: Tor Jeremiassen 
Assisted-by: Claude:claude-opus-4.6
Signed-off-by: Arnaldo Carvalho de Melo 
Signed-off-by: Sasha Levin

perf machine: Use snprintf() for guestmount path construction

2026-07-24T14:16:29+00:00

[ Upstream commit fe63d3bca288c5bb983304efd5fc3a5ff3183403 ]

machines__findnew() and machines__create_guest_kernel_maps() use
sprintf() to build paths by prepending symbol_conf.guestmount.
Both write into PATH_MAX stack buffers, but guestmount comes from
user configuration and is not length-checked.  A guestmount path
at or near PATH_MAX causes a stack buffer overflow.

Switch to snprintf() with sizeof() to prevent overflow.  The
subsequent access()/fopen() calls will fail on a truncated path.

Fixes: a1645ce12adb6c9c ("perf: 'perf kvm' tool for monitoring guest performance from host")
Reported-by: sashiko-bot 
Cc: Zhang, Yanmin 
Assisted-by: Claude:claude-opus-4.6
Signed-off-by: Arnaldo Carvalho de Melo 
Signed-off-by: Sasha Levin

perf cs-etm: Reject CPU IDs that would overflow signed comparison

2026-07-24T14:16:28+00:00

[ Upstream commit 542e88a4c6f7b6edd1326ce767d4cb3c2ea9d61d ]

metadata[j][CS_ETM_CPU] is a u64 from perf.data, but the comparison
with max_cpu casts it to (int).  A crafted value like 0xFFFFFFFF becomes
-1 after the cast, which compares less than max_cpu (0), so the queue
array is never sized to accommodate it.  When the value is later passed
to cs_etm__get_queue(), it indexes queue_array with the original large
value, causing an out-of-bounds access.

Validate that CS_ETM_CPU fits in an int before using it in the signed
comparison.

Fixes: 57880a7966be510c ("perf: cs-etm: Allocate queues for all CPUs")
Reported-by: sashiko-bot 
Cc: James Clark 
Cc: Adrian Hunter 
Assisted-by: Claude:claude-opus-4.6
Signed-off-by: Arnaldo Carvalho de Melo 
Signed-off-by: Sasha Levin