[PATCH 4.9 30/59] perf evsel: Fix potential null pointer dereference in perf_evsel__new_idx()

Greg Kroah-Hartman
2018-10-08T18:39:20Z

From: Hisao Tanabe <xtanabe@gmail.com>

[ Upstream commit fd8d2702791a970c751f8b526a17d8e725a05b46 ]

If evsel is NULL, we should return NULL to avoid a NULL pointer
dereference a bit later in the code.

Signed-off-by: Hisao Tanabe <xtanabe@gmail.com>
Acked-by: Namhyung Kim <namhyung@kernel.org>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Wang Nan <wangnan0@huawei.com>
Fixes: 03e0a7df3efd ("perf tools: Introduce bpf-output event")
LPU-Reference: 20180824154556.23428-1-xtanabe@gmail.com
Link: https://lkml.kernel.org/n/tip-e5plzjhx6595a5yjaf22jss3@git.kernel.org
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Signed-off-by: Sasha Levin <alexander.levin@microsoft.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
tools/perf/util/evsel.c | 5 +++--
1 file changed, 3 insertions(+), 2 deletions(-)

--- a/tools/perf/util/evsel.c
+++ b/tools/perf/util/evsel.c
@@ -241,8 +241,9 @@ struct perf_evsel *perf_evsel__new_idx(s
{
struct perf_evsel *evsel = zalloc(perf_evsel__object.size);

- if (evsel != NULL)
- perf_evsel__init(evsel, attr, idx);
+ if (!evsel)
+ return NULL;
+ perf_evsel__init(evsel, attr, idx);

if (perf_evsel__is_bpf_output(evsel)) {
evsel->attr.sample_type |= (PERF_SAMPLE_RAW | PERF_SAMPLE_TIME |