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perf stat: Fix segfault for event group in repeat mode 

Numfor Mbiziwo-Tiapo reported segfault on stat of event group in repeat
mode:

  # perf stat -e '{cycles,instructions}' -r 10 ls

It's caused by memory corruption due to not cleaned evsel's id array and
index, which needs to be rebuilt in every stat iteration. Currently the
ids index grows, while the array (which is also not freed) has the same
size.

Fixing this by releasing id array and zeroing ids index in
perf_evsel__close function.

We also need to keep the evsel_list alive for stat record (which is
disabled in repeat mode).

Reported-by: Numfor Mbiziwo-Tiapo <nums@google.com>
Signed-off-by: Jiri Olsa <jolsa@kernel.org>
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: Ian Rogers <irogers@google.com>
Cc: Mark Drayton <mbd@fb.com>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Song Liu <songliubraving@fb.com>
Cc: Stephane Eranian <eranian@google.com>
Link: http://lkml.kernel.org/r/20190715142121.GC6032@krava
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
This commit is contained in:
Jiri Olsa 2019-07-15 16:21:21 +02:00 committed by Arnaldo Carvalho de Melo
parent 79b2fe5e75
commit 08ef3af157
2 changed files with 10 additions and 1 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

9
tools/perf/builtin-stat.c
View File

@ -607,7 +607,13 @@ static int __run_perf_stat(int argc, const char **argv, int run_idx)
* group leaders.
*/
read_counters(&(struct timespec) { .tv_nsec = t1-t0 });
perf_evlist__close(evsel_list);
/*
* We need to keep evsel_list alive, because it's processed
* later the evsel_list will be closed after.
*/
if (!STAT_RECORD)
perf_evlist__close(evsel_list);
return WEXITSTATUS(status);
}
@ -1997,6 +2003,7 @@ int cmd_stat(int argc, const char **argv)
perf_session__write_header(perf_stat.session, evsel_list, fd, true);
}
perf_evlist__close(evsel_list);
perf_session__delete(perf_stat.session);
}

2
tools/perf/util/evsel.c
View File

@ -1291,6 +1291,7 @@ static void perf_evsel__free_id(struct perf_evsel *evsel)
xyarray__delete(evsel->sample_id);
evsel->sample_id = NULL;
zfree(&evsel->id);
evsel->ids = 0;
}
static void perf_evsel__free_config_terms(struct perf_evsel *evsel)
@ -2077,6 +2078,7 @@ void perf_evsel__close(struct perf_evsel *evsel)
perf_evsel__close_fd(evsel);
perf_evsel__free_fd(evsel);
perf_evsel__free_id(evsel);
}
int perf_evsel__open_per_cpu(struct perf_evsel *evsel,