[PATCH v1 07/11] perf map: Smatch: Fix potential NULL pointer dereference

Leo Yan
2019-07-02T10:37:29Z

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

tools/perf/util/map.c:479
map__fprintf_srccode() error: we previously assumed 'state' could be
null (see line 466)

tools/perf/util/map.c
465 /* Avoid redundant printing */
466 if (state &&
467 state->srcfile &&
468 !strcmp(state->srcfile, srcfile) &&
469 state->line == line) {
470 free(srcfile);
471 return 0;
472 }
473
474 srccode = find_sourceline(srcfile, line, &len);
475 if (!srccode)
476 goto out_free_line;
477
478 ret = fprintf(fp, "|%-8d %.*s", line, len, srccode);
479 state->srcfile = srcfile;
^^^^^^^
480 state->line = line;
^^^^^^^

This patch validates 'state' pointer before access its elements.

Signed-off-by: Leo Yan <leo.yan@linaro.org>
---
tools/perf/util/map.c | 7 +++++--
1 file changed, 5 insertions(+), 2 deletions(-)

diff --git a/tools/perf/util/map.c b/tools/perf/util/map.c
index 6fce983c6115..5f87975d2562 100644
--- a/tools/perf/util/map.c
+++ b/tools/perf/util/map.c
@@ -476,8 +476,11 @@ int map__fprintf_srccode(struct map *map, u64 addr,
goto out_free_line;

ret = fprintf(fp, "|%-8d %.*s", line, len, srccode);
- state->srcfile = srcfile;
- state->line = line;
+
+ if (state) {
+ state->srcfile = srcfile;
+ state->line = line;
+ }
return ret;

out_free_line:
--
2.17.1