[PATCH v1 03/11] perf top: Smatch: Fix potential NULL pointer dereference

Leo Yan
2019-07-02T10:36:05Z

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

tools/perf/builtin-top.c:109
perf_top__parse_source() warn: variable dereferenced before check 'he'
(see line 103)

tools/perf/builtin-top.c:233
perf_top__show_details() warn: variable dereferenced before check 'he'
(see line 228)

tools/perf/builtin-top.c
101 static int perf_top__parse_source(struct perf_top *top, struct hist_entry *he)
102 {
103 struct perf_evsel *evsel = hists_to_evsel(he->hists);
^^^^
104 struct symbol *sym;
105 struct annotation *notes;
106 struct map *map;
107 int err = -1;
108
109 if (!he || !he->ms.sym)
110 return -1;

This patch moves the values assignment after validating pointer 'he'.

Signed-off-by: Leo Yan <leo.yan@linaro.org>
---
tools/perf/builtin-top.c | 8 ++++++--
1 file changed, 6 insertions(+), 2 deletions(-)

diff --git a/tools/perf/builtin-top.c b/tools/perf/builtin-top.c
index 12b6b15a9675..13234c322981 100644
--- a/tools/perf/builtin-top.c
+++ b/tools/perf/builtin-top.c
@@ -100,7 +100,7 @@ static void perf_top__resize(struct perf_top *top)

static int perf_top__parse_source(struct perf_top *top, struct hist_entry *he)
{
- struct perf_evsel *evsel = hists_to_evsel(he->hists);
+ struct perf_evsel *evsel;
struct symbol *sym;
struct annotation *notes;
struct map *map;
@@ -109,6 +109,8 @@ static int perf_top__parse_source(struct perf_top *top, struct hist_entry *he)
if (!he || !he->ms.sym)
return -1;

+ evsel = hists_to_evsel(he->hists);
+
sym = he->ms.sym;
map = he->ms.map;

@@ -225,7 +227,7 @@ static void perf_top__record_precise_ip(struct perf_top *top,
static void perf_top__show_details(struct perf_top *top)
{
struct hist_entry *he = top->sym_filter_entry;
- struct perf_evsel *evsel = hists_to_evsel(he->hists);
+ struct perf_evsel *evsel;
struct annotation *notes;
struct symbol *symbol;
int more;
@@ -233,6 +235,8 @@ static void perf_top__show_details(struct perf_top *top)
if (!he)
return;

+ evsel = hists_to_evsel(he->hists);
+
symbol = he->ms.sym;
notes = symbol__annotation(symbol);

--
2.17.1