linux.git/tools/perf/tests/backward-ring-buffer.c, branch v7.3-rc2

perf evlist: Add reference count checking

2026-06-30T17:17:11+00:00

Now the evlist is reference counted, add reference count checking so
that gets and puts are paired and easy to debug. Reference count
checking is documented here:
https://perfwiki.github.io/main/reference-count-checking/

This large patch is adding accessors to evlist functions and switching
to their use. There was some minor renaming as evlist__mmap is now an
accessor to the mmap variable, and the original evlist__mmap is
renamed to evlist__do_mmap.

Signed-off-by: Ian Rogers 
Cc: Adrian Hunter 
Cc: Alice Rogers 
Cc: Dapeng Mi 
Cc: Ingo Molnar 
Cc: James Clark 
Cc: Leo Yan 
Cc: Namhyung Kim 
Cc: Peter Zijlstra 
Cc: Thomas Richter 
Signed-off-by: Arnaldo Carvalho de Melo 
Signed-off-by: Namhyung Kim

perf evlist: Add reference count

2026-06-30T17:17:10+00:00

This a no-op for most of the perf tool. The reference count is set to
1 at allocation, the put will see the 1, decrement it and perform the
delete.

The purpose for adding the reference count is for the python code. Prior
to this change the python code would clone evlists, but this has issues
if events are opened, etc.

This change adds a reference count for the evlists and a later change
will add it to evsels. The combination is needed for the python code to
operate correctly (not hit asserts in the evsel clone), but the changes
are broken apart for the sake of smaller patches.

Assisted-by: Gemini:gemini-3.1-pro-preview
Signed-off-by: Ian Rogers 
Cc: Adrian Hunter 
Cc: Alice Rogers 
Cc: Dapeng Mi 
Cc: Ingo Molnar 
Cc: James Clark 
Cc: Leo Yan 
Cc: Namhyung Kim 
Cc: Peter Zijlstra 
Cc: Thomas Richter 
Signed-off-by: Arnaldo Carvalho de Melo 
Signed-off-by: Namhyung Kim

perf target: Remove uid from target

2025-06-09T18:18:18+00:00

Gathering threads with a uid by scanning /proc is inherently racy
leading to perf_event_open failures that quit perf. All users of the
functionality now use BPF filters, so remove uid and uid_str from
target.

Signed-off-by: Ian Rogers 
Link: https://lore.kernel.org/r/20250604174545.2853620-10-irogers@google.com
Signed-off-by: Namhyung Kim

perf test: Rename struct test to test_suite

2021-11-13T13:32:22+00:00

This is to align with kunit's terminology.

Signed-off-by: Ian Rogers 
Tested-by: Sohaib Mohamed 
Acked-by: Jiri Olsa 
Cc: Alexander Shishkin 
Cc: Brendan Higgins 
Cc: Daniel Latypov 
Cc: David Gow 
Cc: Ingo Molnar 
Cc: Jin Yao 
Cc: John Garry 
Cc: Mark Rutland 
Cc: Namhyung Kim 
Cc: Paul Clarke 
Cc: Peter Zijlstra 
Cc: Stephane Eranian 
Link: https://lore.kernel.org/r/20211104064208.3156807-6-irogers@google.com
Signed-off-by: Arnaldo Carvalho de Melo

perf test: Move each test suite struct to its test

2021-11-13T13:30:58+00:00

Rather than export test functions, export the test struct. Rename with a
suite__ prefix to avoid name collisions.

Committer notes:

Its '&suite__vectors_page', not '&suite__vectors_pages', noticed when
cross building to arm (32-bit).

Signed-off-by: Ian Rogers 
Tested-by: Sohaib Mohamed 
Acked-by: Jiri Olsa 
Cc: Alexander Shishkin 
Cc: Brendan Higgins 
Cc: Daniel Latypov 
Cc: David Gow 
Cc: Ingo Molnar 
Cc: Jin Yao 
Cc: John Garry 
Cc: Mark Rutland 
Cc: Namhyung Kim 
Cc: Paul Clarke 
Cc: Peter Zijlstra 
Cc: Stephane Eranian 
Link: https://lore.kernel.org/r/20211104064208.3156807-5-irogers@google.com
Signed-off-by: Arnaldo Carvalho de Melo

perf parse-event: Add init and exit to parse_event_error

2021-11-07T18:39:25+00:00

parse_events() may succeed but leave string memory allocations reachable
in the error.

Add an init/exit that must be called to initialize and clean up the
error. This fixes a leak in metricgroup parse_ids.

Signed-off-by: Ian Rogers 
Cc: Alexander Shishkin 
Cc: Jiri Olsa 
Cc: John Garry 
Cc: Mark Rutland 
Cc: Namhyung Kim 
Cc: Peter Zijlstra 
Cc: Stephane Eranian 
Link: http://lore.kernel.org/lkml/20211107090002.3784612-2-irogers@google.com
Signed-off-by: Arnaldo Carvalho de Melo

perf evlist: Use the right prefix for 'struct evlist' event attribute config methods

2020-11-30T18:15:27+00:00

perf_evlist__ is for 'struct perf_evlist' methods, in tools/lib/perf/,
go on completing this split.

Cc: Adrian Hunter 
Cc: Ian Rogers 
Cc: Jiri Olsa 
Cc: Namhyung Kim 
Signed-off-by: Arnaldo Carvalho de Melo

perf evlist: Use the right prefix for 'struct evlist' create maps methods

2020-11-30T17:56:52+00:00

perf_evlist__ is for 'struct perf_evlist' methods, in tools/lib/perf/,
go on completing this split.

Cc: Adrian Hunter 
Cc: Ian Rogers 
Cc: Jiri Olsa 
Cc: Namhyung Kim 
Signed-off-by: Arnaldo Carvalho de Melo

perf tests: Fix out of bounds memory access

2019-11-07T12:04:22+00:00

The test case 'Read backward ring buffer' failed on 32-bit architectures
which were found by LKFT perf testing.  The test failed on arm32 x15
device, qemu_arm32, qemu_i386, and found intermittent failure on i386;
the failure log is as below:

  50: Read backward ring buffer                  :
  --- start ---
  test child forked, pid 510
  Using CPUID GenuineIntel-6-9E-9
  mmap size 1052672B
  mmap size 8192B
  Finished reading overwrite ring buffer: rewind
  free(): invalid next size (fast)
  test child interrupted
  ---- end ----
  Read backward ring buffer: FAILED!

The log hints there have issue for memory usage, thus free() reports
error 'invalid next size' and directly exit for the case.  Finally, this
issue is root caused as out of bounds memory access for the data array
'evsel->id'.

The backward ring buffer test invokes do_test() twice.  'evsel->id' is
allocated at the first call with the flow:

  test__backward_ring_buffer()
    `-> do_test()
	  `-> evlist__mmap()
	        `-> evlist__mmap_ex()
	              `-> perf_evsel__alloc_id()

So 'evsel->id' is allocated with one item, and it will be used in
function perf_evlist__id_add():

   evsel->id[0] = id
   evsel->ids   = 1

At the second call for do_test(), it skips to initialize 'evsel->id'
and reuses the array which is allocated in the first call.  But
'evsel->ids' contains the stale value.  Thus:

   evsel->id[1] = id    -> out of bound access
   evsel->ids   = 2

To fix this issue, we will use evlist__open() and evlist__close() pair
functions to prepare and cleanup context for evlist; so 'evsel->id' and
'evsel->ids' can be initialized properly when invoke do_test() and avoid
the out of bounds memory access.

Fixes: ee74701ed8ad ("perf tests: Add test to check backward ring buffer")
Signed-off-by: Leo Yan 
Reviewed-by: Jiri Olsa 
Cc: Alexander Shishkin 
Cc: Mark Rutland 
Cc: Namhyung Kim 
Cc: Naresh Kamboju 
Cc: Peter Zijlstra 
Cc: Wang Nan 
Cc: stable@vger.kernel.org # v4.10+
Link: http://lore.kernel.org/lkml/20191107020244.2427-1-leo.yan@linaro.org
Signed-off-by: Arnaldo Carvalho de Melo

libperf: Adopt perf_mmap__read_event() from tools/perf

2019-10-10T14:49:46+00:00

Move perf_mmap__read_event() from tools/perf to libperf and export it in
the perf/mmap.h header.

Signed-off-by: Jiri Olsa 
Cc: Alexander Shishkin 
Cc: Michael Petlan 
Cc: Namhyung Kim 
Cc: Peter Zijlstra 
Link: http://lore.kernel.org/lkml/20191007125344.14268-13-jolsa@kernel.org
Signed-off-by: Arnaldo Carvalho de Melo