perf evlist: Check 'base' pointer before checking refcnt when put a mmap

[cascardo/linux.git] / tools / perf / util / evlist.c

diff --git a/tools/perf/util/evlist.c b/tools/perf/util/evlist.c
index 50d7b80..58ede32 100644 (file)
--- a/tools/perf/util/evlist.c
+++ b/tools/perf/util/evlist.c
@@ -856,9 +856,11 @@ static void perf_evlist__mmap_get(struct perf_evlist *evlist, int idx)
 
 static void perf_evlist__mmap_put(struct perf_evlist *evlist, int idx)
 {
-       BUG_ON(atomic_read(&evlist->mmap[idx].refcnt) == 0);
+       struct perf_mmap *md = &evlist->mmap[idx];
+
+       BUG_ON(md->base && atomic_read(&md->refcnt) == 0);
 
-       if (atomic_dec_and_test(&evlist->mmap[idx].refcnt))
+       if (atomic_dec_and_test(&md->refcnt))
                __perf_evlist__munmap(evlist, idx);
 }