From: Kan Liang <[email protected]>
There is segmentation fault when running perf trace. For example,
[root@jouet e]# perf trace -e *chdir -o /tmp/bla perf report
--ignore-vmlinux -i ../perf.data
The perf_mmap__consume() could unmap the mmap. It needs to check the
refcnt in perf_mmap__read_done().
Fixes: ee023de05f35 ("perf mmap: Introduce perf_mmap__read_done()")
Reported-by: Arnaldo Carvalho de Melo <[email protected]>
Signed-off-by: Kan Liang <[email protected]>
---
tools/perf/util/mmap.c | 6 ++++++
1 file changed, 6 insertions(+)
diff --git a/tools/perf/util/mmap.c b/tools/perf/util/mmap.c
index 38ca3ff..f6cfc52 100644
--- a/tools/perf/util/mmap.c
+++ b/tools/perf/util/mmap.c
@@ -317,5 +317,11 @@ int perf_mmap__push(struct perf_mmap *md, void *to,
*/
void perf_mmap__read_done(struct perf_mmap *map)
{
+ /*
+ * Check if event was unmapped due to a POLLHUP/POLLERR.
+ */
+ if (!refcount_read(&map->refcnt))
+ return;
+
map->prev = perf_mmap__read_head(map);
}
--
2.4.11
