Commit 7736627b865d ("perf stat: Use affinity for closing file
descriptors") will use FD(evsel, cpu, thread) to read and write
file descriptors xyarray. For a kernel PMU event, this leads to
serious memory corruption and perf crash.
I have seen evlist->core.cpus->nr is 1 while evsel has cpus->nr
with the total number of CPUs. so xyarray which is allocated by
evlist->core.cpus->nr will get overflow. This leads to various
segmentation faults in perf tool for kernel PMU events, eg:
./perf stat -e bus_cycles sleep 1
*** Error in `./perf': free(): invalid next size (fast): 0x00000000401e6370 ***
Aborted (core dumped)
Fixes: 7736627b865d ("perf stat: Use affinity for closing file descriptors")
Cc: Andi Kleen <[email protected]>
Cc: Peter Zijlstra <[email protected]>
Cc: Ingo Molnar <[email protected]>
Cc: Arnaldo Carvalho de Melo <[email protected]>
Cc: Mark Rutland <[email protected]>
Cc: Alexander Shishkin <[email protected]>
Cc: Jiri Olsa <[email protected]>
Cc: Namhyung Kim <[email protected]>
Cc: Adrian Hunter <[email protected]>
Cc: Alexey Budankov <[email protected]>
Signed-off-by: Barry Song <[email protected]>
---
tools/perf/util/evlist.c | 8 ++++++--
1 file changed, 6 insertions(+), 2 deletions(-)
diff --git a/tools/perf/util/evlist.c b/tools/perf/util/evlist.c
index c0768c6..3022152 100644
--- a/tools/perf/util/evlist.c
+++ b/tools/perf/util/evlist.c
@@ -1226,10 +1226,14 @@ void evlist__close(struct evlist *evlist)
int cpu, i;
/*
- * With perf record core.cpus is usually NULL.
+ * With perf record core.cpus is usually NULL;
+ * For Kernel PMU event x, "perf stat -e x" will set
evlist->core.cpus->nr to
+ * 1 while evsel has cpus->nr which contains all CPUs.
evsel__cpu_iter_skip()
+ * will be false, memory corruption will happen if we use affinity to
close
+ * file descriptors;
* Use the old method to handle this for now.
*/
- if (!evlist->core.cpus) {
+ if (!evlist->core.cpus || evlist->core.cpus->nr == 1) {
evlist__for_each_entry_reverse(evlist, evsel)
evsel__close(evsel);
return;
--
2.7.4
