[PATCH 20/25] perf hists browser: Fix potential NULL pointer dereference found by the smatch tool

From: Arnaldo Carvalho de Melo
Date: Tue Jul 09 2019 - 14:33:21 EST


From: Leo Yan <leo.yan@xxxxxxxxxx>

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

tools/perf/ui/browsers/hists.c:641
hist_browser__run() error: we previously assumed 'hbt' could be
null (see line 625)

tools/perf/ui/browsers/hists.c:3088
perf_evsel__hists_browse() error: we previously assumed
'browser->he_selection' could be null (see line 2902)

tools/perf/ui/browsers/hists.c:3272
perf_evsel_menu__run() error: we previously assumed 'hbt' could be
null (see line 3260)

This patch firstly validating the pointers before access them, so can
fix potential NULL pointer dereference.

Signed-off-by: Leo Yan <leo.yan@xxxxxxxxxx>
Acked-by: Jiri Olsa <jolsa@xxxxxxxxxx>
Cc: Adrian Hunter <adrian.hunter@xxxxxxxxx>
Cc: Alexander Shishkin <alexander.shishkin@xxxxxxxxxxxxxxx>
Cc: Andi Kleen <ak@xxxxxxxxxxxxxxx>
Cc: Mathieu Poirier <mathieu.poirier@xxxxxxxxxx>
Cc: Namhyung Kim <namhyung@xxxxxxxxxx>
Cc: Suzuki Poulouse <suzuki.poulose@xxxxxxx>
Cc: linux-arm-kernel@xxxxxxxxxxxxxxxxxxx
Link: http://lkml.kernel.org/r/20190708143937.7722-2-leo.yan@xxxxxxxxxx
Signed-off-by: Arnaldo Carvalho de Melo <acme@xxxxxxxxxx>
---
tools/perf/ui/browsers/hists.c | 15 +++++++++++----
1 file changed, 11 insertions(+), 4 deletions(-)

diff --git a/tools/perf/ui/browsers/hists.c b/tools/perf/ui/browsers/hists.c
index 85581cfb9112..a94eb0755e8b 100644
--- a/tools/perf/ui/browsers/hists.c
+++ b/tools/perf/ui/browsers/hists.c
@@ -639,7 +639,11 @@ int hist_browser__run(struct hist_browser *browser, const char *help,
switch (key) {
case K_TIMER: {
u64 nr_entries;
- hbt->timer(hbt->arg);
+
+ WARN_ON_ONCE(!hbt);
+
+ if (hbt)
+ hbt->timer(hbt->arg);

if (hist_browser__has_filter(browser) ||
symbol_conf.report_hierarchy)
@@ -2821,7 +2825,7 @@ static int perf_evsel__hists_browse(struct perf_evsel *evsel, int nr_events,
{
struct hists *hists = evsel__hists(evsel);
struct hist_browser *browser = perf_evsel_browser__new(evsel, hbt, env, annotation_opts);
- struct branch_info *bi;
+ struct branch_info *bi = NULL;
#define MAX_OPTIONS 16
char *options[MAX_OPTIONS];
struct popup_action actions[MAX_OPTIONS];
@@ -3087,7 +3091,9 @@ static int perf_evsel__hists_browse(struct perf_evsel *evsel, int nr_events,
goto skip_annotation;

if (sort__mode == SORT_MODE__BRANCH) {
- bi = browser->he_selection->branch_info;
+
+ if (browser->he_selection)
+ bi = browser->he_selection->branch_info;

if (bi == NULL)
goto skip_annotation;
@@ -3271,7 +3277,8 @@ static int perf_evsel_menu__run(struct perf_evsel_menu *menu,

switch (key) {
case K_TIMER:
- hbt->timer(hbt->arg);
+ if (hbt)
+ hbt->timer(hbt->arg);

if (!menu->lost_events_warned &&
menu->lost_events &&
--
2.21.0