[PATCH v1 11/11] perf cs-etm: Smatch: Fix potential NULL pointer dereference

Leo Yan
2019-07-02T10:36:14Z

Based on the following report from Smatch, fix the potential
NULL pointer dereference check.

tools/perf/util/cs-etm.c:2545
cs_etm__process_auxtrace_info() error: we previously assumed
'session->itrace_synth_opts' could be null (see line 2541)

tools/perf/util/cs-etm.c
2541 if (session->itrace_synth_opts && session->itrace_synth_opts->set) {
2542 etm->synth_opts = *session->itrace_synth_opts;
2543 } else {
2544 itrace_synth_opts__set_default(&etm->synth_opts,
2545 session->itrace_synth_opts->default_no_sample);
^^^^^^^^^^^^^^^^^^^^^^^^^^
2546 etm->synth_opts.callchain = false;
2547 }

To dismiss the potential NULL pointer dereference, this patch validates
the pointer 'session->itrace_synth_opts' before access its elements.

Signed-off-by: Leo Yan <leo.yan@linaro.org>
---
tools/perf/util/cs-etm.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/tools/perf/util/cs-etm.c b/tools/perf/util/cs-etm.c
index 0c7776b51045..b79df56eb9df 100644
--- a/tools/perf/util/cs-etm.c
+++ b/tools/perf/util/cs-etm.c
@@ -2540,7 +2540,7 @@ int cs_etm__process_auxtrace_info(union perf_event *event,

if (session->itrace_synth_opts && session->itrace_synth_opts->set) {
etm->synth_opts = *session->itrace_synth_opts;
- } else {
+ } else if (session->itrace_synth_opts) {
itrace_synth_opts__set_default(&etm->synth_opts,
session->itrace_synth_opts->default_no_sample);
etm->synth_opts.callchain = false;
--
2.17.1