[PATCH 24/25] perf intel-bts: Fix potential NULL pointer dereference found by the smatch tool

Arnaldo Carvalho de Melo
2019-07-09T18:33:27Z

From: Leo Yan <leo.yan@linaro.org>

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

tools/perf/util/intel-bts.c:898
intel_bts_process_auxtrace_info() error: we previously assumed
'session->itrace_synth_opts' could be null (see line 894)

tools/perf/util/intel-bts.c:899
intel_bts_process_auxtrace_info() warn: variable dereferenced before
check 'session->itrace_synth_opts' (see line 898)

tools/perf/util/intel-bts.c
894 if (session->itrace_synth_opts && session->itrace_synth_opts->set) {
895 bts->synth_opts = *session->itrace_synth_opts;
896 } else {
897 itrace_synth_opts__set_default(&bts->synth_opts,
898 session->itrace_synth_opts->default_no_sample);
^^^^^^^^^^^^^^^^^^^^^^^^^^
899 if (session->itrace_synth_opts)
^^^^^^^^^^^^^^^^^^^^^^^^^^
900 bts->synth_opts.thread_stack =
901 session->itrace_synth_opts->thread_stack;
902 }

'session->itrace_synth_opts' is impossible to be a NULL pointer in
intel_bts_process_auxtrace_info(), thus this patch removes the NULL test
for 'session->itrace_synth_opts'.

Signed-off-by: Leo Yan <leo.yan@linaro.org>
Acked-by: Adrian Hunter <adrian.hunter@intel.com>
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: Andi Kleen <ak@linux.intel.com>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Mathieu Poirier <mathieu.poirier@linaro.org>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Suzuki Poulouse <suzuki.poulose@arm.com>
Cc: linux-arm-kernel@lists.infradead.org
Link: http://lkml.kernel.org/r/20190708143937.7722-3-leo.yan@linaro.org
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
---
tools/perf/util/intel-bts.c | 5 ++---
1 file changed, 2 insertions(+), 3 deletions(-)

diff --git a/tools/perf/util/intel-bts.c b/tools/perf/util/intel-bts.c
index 5a21bcdb8ef7..5560e95afdda 100644
--- a/tools/perf/util/intel-bts.c
+++ b/tools/perf/util/intel-bts.c
@@ -891,13 +891,12 @@ int intel_bts_process_auxtrace_info(union perf_event *event,
if (dump_trace)
return 0;

- if (session->itrace_synth_opts && session->itrace_synth_opts->set) {
+ if (session->itrace_synth_opts->set) {
bts->synth_opts = *session->itrace_synth_opts;
} else {
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 =
+ bts->synth_opts.thread_stack =
session->itrace_synth_opts->thread_stack;
}

--
2.21.0