4.20-stable review patch. If anyone has any objections, please let me know. ------------------ [ Upstream commit 99d86c8b88393e29cf07c020585f2c8afbcdd97d ] Song Liu reported crash in 'perf record': > #0 0x0000000000500055 in ordered_events(float, long double,...)(...) () > #1 0x0000000000500196 in ordered_events.reinit () > #2 0x00000000004fe413 in perf_session.process_events () > #3 0x0000000000440431 in cmd_record () > #4 0x00000000004a439f in run_builtin () > #5 0x000000000042b3e5 in main ()" This can happen when we get out of buffers during event processing. The subsequent ordered_events__free() call assumes oe->buffer != NULL and crashes. Add a check to prevent that. Reported-by: Song Liu <liu.song.a23@xxxxxxxxx> Signed-off-by: Jiri Olsa <jolsa@xxxxxxxxxx> Reviewed-by: Song Liu <liu.song.a23@xxxxxxxxx> Tested-by: Song Liu <liu.song.a23@xxxxxxxxx> Cc: Alexander Shishkin <alexander.shishkin@xxxxxxxxxxxxxxx> Cc: Namhyung Kim <namhyung@xxxxxxxxxx> Cc: Peter Zijlstra <peterz@xxxxxxxxxxxxx> Cc: Stephane Eranian <eranian@xxxxxxxxxx> Link: http://lkml.kernel.org/r/20190117113017.12977-1-jolsa@xxxxxxxxxx Fixes: d5ceb62b3654 ("perf ordered_events: Add 'struct ordered_events_buffer' layer") Signed-off-by: Arnaldo Carvalho de Melo <acme@xxxxxxxxxx> Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx> --- tools/perf/util/ordered-events.c | 6 ++++-- 1 file changed, 4 insertions(+), 2 deletions(-) diff --git a/tools/perf/util/ordered-events.c b/tools/perf/util/ordered-events.c index 1904e7f6ec84..77126a5fa9b6 100644 --- a/tools/perf/util/ordered-events.c +++ b/tools/perf/util/ordered-events.c @@ -359,8 +359,10 @@ void ordered_events__free(struct ordered_events *oe) * Current buffer might not have all the events allocated * yet, we need to free only allocated ones ... */ - list_del(&oe->buffer->list); - ordered_events_buffer__free(oe->buffer, oe->buffer_idx, oe); + if (oe->buffer) { + list_del(&oe->buffer->list); + ordered_events_buffer__free(oe->buffer, oe->buffer_idx, oe); + } /* ... and continue with the rest */ list_for_each_entry_safe(buffer, tmp, &oe->to_free, list) { -- 2.19.1
