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authorKan Liang <kan.liang@linux.intel.com>2018-03-26 09:42:09 -0400
committerArnaldo Carvalho de Melo <acme@redhat.com>2018-03-27 13:13:38 -0300
commitf58385f629c87a9e210108b39c1f4950d0363ad2 (patch)
tree532b5e34e645af4984155e187d2737e38a57f2fc /tools
parentb4c786e5aa69c5a75ac3932f81fdf8e8c120c03b (diff)
perf mmap: Fix accessing unmapped mmap in perf_mmap__read_done()
There is a 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(). Reported-by: Arnaldo Carvalho de Melo <acme@redhat.com> Signed-off-by: Kan Liang <kan.liang@linux.intel.com> Cc: Jiri Olsa <jolsa@kernel.org> Cc: Namhyung Kim <namhyung@kernel.org> Cc: Wang Nan <wangnan0@huawei.com> Fixes: ee023de05f35 ("perf mmap: Introduce perf_mmap__read_done()") Link: http://lkml.kernel.org/r/1522071729-16776-1-git-send-email-kan.liang@linux.intel.com Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Diffstat (limited to 'tools')
-rw-r--r--tools/perf/util/mmap.c6
1 files changed, 6 insertions, 0 deletions
diff --git a/tools/perf/util/mmap.c b/tools/perf/util/mmap.c
index 38ca3ffb9d61..f6cfc52ff1fe 100644
--- a/tools/perf/util/mmap.c
+++ b/tools/perf/util/mmap.c
@@ -317,5 +317,11 @@ out:
*/
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);
}