[PATCH] perf script: Fix segfault using --show-mmap-events

From: Adrian Hunter
Date: Thu Aug 20 2015 - 04:29:56 EST


Patch "perf script: Don't assume evsel position of tracking events"
changed 'perf script' to use 'perf_evlist__id2evsel()'. That results
in a segfault if there is more than 1 event and there are
synthesized mmap events e.g.

$ perf record -e cycles,instructions -p$$ sleep 1
$ perf script --show-mmap-events
Segmentation fault (core dumped)

That happens because these synthesized events have an 'id' of zero
which does not match any 'evsel'.

Currently, these synthesized events use the sample type of the first
evsel.

Change 'perf_evlist__id2evsel()' to reflect that which also makes
it consistent with 'perf_evlist__event2evsel()'.

Signed-off-by: Adrian Hunter <adrian.hunter@xxxxxxxxx>
---
tools/perf/util/evlist.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/tools/perf/util/evlist.c b/tools/perf/util/evlist.c
index 373f65b02545..e9a5d432902c 100644
--- a/tools/perf/util/evlist.c
+++ b/tools/perf/util/evlist.c
@@ -573,7 +573,7 @@ struct perf_evsel *perf_evlist__id2evsel(struct perf_evlist *evlist, u64 id)
{
struct perf_sample_id *sid;

- if (evlist->nr_entries == 1)
+ if (evlist->nr_entries == 1 || !id)
return perf_evlist__first(evlist);

sid = perf_evlist__id2sid(evlist, id);
--
1.9.1

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