[PATCH 4/4] perf intel-pt/bts: fix potential NULL pointer dereference in intel_bts_process_auxtrace_info

[Wen Yang]

This patch fixes a possible null pointer dereference in
intel_bts_process_auxtrace_info, detected by the semantic patch
deref_null.cocci, with the following warning:

./tools/perf/util/intel-bts.c:921:32-49: ERROR: session -> itrace_synth_opts is NULL but dereferenced.

Signed-off-by: Wen Yang <wen.yang99@xxxxxxxxxx>
Reviewed-by: Tan Hu <tan.hu@xxxxxxxxxx>
CC: Julia Lawall <julia.lawall@xxxxxxx>
---
 tools/perf/util/intel-bts.c | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/tools/perf/util/intel-bts.c b/tools/perf/util/intel-bts.c
index 7b27d77..b0258f4 100644
--- a/tools/perf/util/intel-bts.c
+++ b/tools/perf/util/intel-bts.c
@@ -917,7 +917,8 @@ int intel_bts_process_auxtrace_info(union perf_event *event,
 	if (session->itrace_synth_opts && session->itrace_synth_opts->set) {
 		bts->synth_opts = *session->itrace_synth_opts;
 	} else {
-		itrace_synth_opts__set_default(&bts->synth_opts,
+		if (session->itrace_synth_opts)
+			itrace_synth_opts__set_default(&bts->synth_opts,
 				session->itrace_synth_opts->default_no_sample);
 		if (session->itrace_synth_opts)
 			bts->synth_opts.thread_stack =
-- 
2.9.5