diff options
| author | Shuai Xue <xueshuai@linux.alibaba.com> | 2025-10-23 09:50:43 +0800 |
|---|---|---|
| committer | Namhyung Kim <namhyung@kernel.org> | 2025-10-31 12:01:02 -0700 |
| commit | 163e5f2b96632b7fb2eaa965562aca0dbdf9f996 (patch) | |
| tree | 2125fe32e935feaa40acf55afa59814646e1114a /tools | |
| parent | 553d18c98a896094b99a01765b9698b204183d49 (diff) | |
perf record: skip synthesize event when open evsel failed
When using perf record with the `--overwrite` option, a segmentation fault
occurs if an event fails to open. For example:
perf record -e cycles-ct -F 1000 -a --overwrite
Error:
cycles-ct:H: PMU Hardware doesn't support sampling/overflow-interrupts. Try 'perf stat'
perf: Segmentation fault
#0 0x6466b6 in dump_stack debug.c:366
#1 0x646729 in sighandler_dump_stack debug.c:378
#2 0x453fd1 in sigsegv_handler builtin-record.c:722
#3 0x7f8454e65090 in __restore_rt libc-2.32.so[54090]
#4 0x6c5671 in __perf_event__synthesize_id_index synthetic-events.c:1862
#5 0x6c5ac0 in perf_event__synthesize_id_index synthetic-events.c:1943
#6 0x458090 in record__synthesize builtin-record.c:2075
#7 0x45a85a in __cmd_record builtin-record.c:2888
#8 0x45deb6 in cmd_record builtin-record.c:4374
#9 0x4e5e33 in run_builtin perf.c:349
#10 0x4e60bf in handle_internal_command perf.c:401
#11 0x4e6215 in run_argv perf.c:448
#12 0x4e653a in main perf.c:555
#13 0x7f8454e4fa72 in __libc_start_main libc-2.32.so[3ea72]
#14 0x43a3ee in _start ??:0
The --overwrite option implies --tail-synthesize, which collects non-sample
events reflecting the system status when recording finishes. However, when
evsel opening fails (e.g., unsupported event 'cycles-ct'), session->evlist
is not initialized and remains NULL. The code unconditionally calls
record__synthesize() in the error path, which iterates through the NULL
evlist pointer and causes a segfault.
To fix it, move the record__synthesize() call inside the error check block, so
it's only called when there was no error during recording, ensuring that evlist
is properly initialized.
Fixes: 4ea648aec019 ("perf record: Add --tail-synthesize option")
Signed-off-by: Shuai Xue <xueshuai@linux.alibaba.com>
Signed-off-by: Namhyung Kim <namhyung@kernel.org>
Diffstat (limited to 'tools')
| -rw-r--r-- | tools/perf/builtin-record.c | 2 |
1 files changed, 1 insertions, 1 deletions
diff --git a/tools/perf/builtin-record.c b/tools/perf/builtin-record.c index cb52aea9607d..ffb94a8339b0 100644 --- a/tools/perf/builtin-record.c +++ b/tools/perf/builtin-record.c @@ -2958,11 +2958,11 @@ out_free_threads: rec->bytes_written += off_cpu_write(rec->session); record__read_lost_samples(rec); - record__synthesize(rec, true); /* this will be recalculated during process_buildids() */ rec->samples = 0; if (!err) { + record__synthesize(rec, true); if (!rec->timestamp_filename) { record__finish_output(rec); } else { |