aboutsummaryrefslogtreecommitdiff
path: root/tools/perf
diff options
context:
space:
mode:
authorWang Nan <wangnan0@huawei.com>2016-05-25 13:44:49 +0000
committerArnaldo Carvalho de Melo <acme@redhat.com>2016-05-25 17:26:35 -0300
commit812c29afed7d2378802c3c95b8d924e2eae220ee (patch)
treeb4a0bfc6d1a940926fe83bb04a39e66f931cf85a /tools/perf
parentbfbd58ff400326ac82d3a0cf4d0b4a223f30abeb (diff)
perf evlist: Check 'base' pointer before checking refcnt when put a mmap
evlist->mmap[i]->refcnt could be 0 if an evlist has no evsel or if all evsels don't match the evlist during mmap. For example, when all evsels are overwritable but the evlist itself is normal. To avoid crashing, perf should check 'base' pointer before checking refcnt, and raise bug only when base is not NULL. Signed-off-by: Wang Nan <wangnan0@huawei.com> Cc: He Kuang <hekuang@huawei.com> Cc: Jiri Olsa <jolsa@kernel.org> Cc: Masami Hiramatsu <mhiramat@kernel.org> Cc: Namhyung Kim <namhyung@kernel.org> Cc: Zefan Li <lizefan@huawei.com> Cc: pi3orama@163.com Link: http://lkml.kernel.org/r/1464183898-174512-2-git-send-email-wangnan0@huawei.com [ Renamed 'mmap' variable, it is reserved in old distros such as Ubuntu 12.04, breaking the build ] Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Diffstat (limited to 'tools/perf')
-rw-r--r--tools/perf/util/evlist.c6
1 files changed, 4 insertions, 2 deletions
diff --git a/tools/perf/util/evlist.c b/tools/perf/util/evlist.c
index 50d7b80987c0..58ede3257c61 100644
--- 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);
}