[PATCH 4.18 090/168] perf evsel: Fix potential null pointer dereference in perf_evsel__new_idx()

[Greg Kroah-Hartman]

4.18-stable review patch.  If anyone has any objections, please let me know.

------------------

From: Hisao Tanabe <xtanabe@xxxxxxxxx>

[ 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@xxxxxxxxx>
Acked-by: Namhyung Kim <namhyung@xxxxxxxxxx>
Cc: Jiri Olsa <jolsa@xxxxxxxxxx>
Cc: Wang Nan <wangnan0@xxxxxxxxxx>
Fixes: 03e0a7df3efd ("perf tools: Introduce bpf-output event")
LPU-Reference: 20180824154556.23428-1-xtanabe@xxxxxxxxx
Link: https://lkml.kernel.org/n/tip-e5plzjhx6595a5yjaf22jss3@xxxxxxxxxxxxxx
Signed-off-by: Arnaldo Carvalho de Melo <acme@xxxxxxxxxx>
Signed-off-by: Sasha Levin <alexander.levin@xxxxxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
 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
@@ -251,8 +251,9 @@ 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 |