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SubjectRe: [PATCH 1/1] perf,tools: fix core dump caused by per-socket/core system-wide stat
On Fri, Oct 09, 2015 at 06:59:23AM -0400, kan.liang@intel.com wrote:
> From: Kan Liang <kan.liang@intel.com>
>
> Perf will core dump if --per-socket/core -a are applied for perf stat.
>
> The root cause is that cpu_map__build_map set refcnt of evlist's cpu_map
> to 1.
> It should set refcnt for the newly created cpu_map, not evlist's
> cpu_map.
>
> Here is the example:
>
> perf stat -e cycles --per-socket -a sleep 1
>
> Performance counter stats for 'system wide':
>
> S0 36 30,196,257 cycles
> S1 28 15,823,536 cycles
>
> 1.001126828 seconds time elapsed
>
> *** Error in `./perf': corrupted double-linked list: 0x00000000021f9090
> ***
> ======= Backtrace: =========
> /lib64/libc.so.6[0x3002e7bbe7]
> /lib64/libc.so.6[0x3002e7d2b5]
> ./perf(perf_evsel__delete+0x28)[0x485bdd]
> ./perf[0x4800e8]
> ./perf(perf_evlist__delete+0x5e)[0x482cd5]
> ./perf(cmd_stat+0xf25)[0x432328]
> ./perf[0x4768e0]
> ./perf[0x476ad6]
> ./perf[0x476b41]
> ./perf(main+0x1d0)[0x476db2]
> /lib64/libc.so.6(__libc_start_main+0xf5)[0x3002e21b45]
> ./perf[0x4202c5]
>
> Signed-off-by: Kan Liang <kan.liang@intel.com>
> ---
> tools/perf/util/cpumap.c | 2 +-
> 1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/tools/perf/util/cpumap.c b/tools/perf/util/cpumap.c
> index c51c29f..dfc1f0b 100644
> --- a/tools/perf/util/cpumap.c
> +++ b/tools/perf/util/cpumap.c
> @@ -284,7 +284,7 @@ static int cpu_map__build_map(struct cpu_map *cpus, struct cpu_map **res,
> /* ensure we process id in increasing order */
> qsort(c->map, c->nr, sizeof(int), cmp_ids);
>
> - atomic_set(&cpus->refcnt, 1);
> + atomic_set(&c->refcnt, 1);

ouch ;-)

Acked-by: Jiri Olsa <jolsa@kernel.org>

thanks,
jirka


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