[PATCH 06/25] perf map: Fix potential NULL pointer dereference found by smatch tool

Arnaldo Carvalho de Melo
2019-07-09T18:32:24Z

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

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>
Acked-by: Jiri Olsa <jolsa@kernel.org>
Cc: Adrian Hunter <adrian.hunter@intel.com>
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: Alexey Budankov <alexey.budankov@linux.intel.com>
Cc: Alexios Zavras <alexios.zavras@intel.com>
Cc: Andi Kleen <ak@linux.intel.com>
Cc: Changbin Du <changbin.du@intel.com>
Cc: David S. Miller <davem@davemloft.net>
Cc: Davidlohr Bueso <dave@stgolabs.net>
Cc: Eric Saint-Etienne <eric.saint.etienne@oracle.com>
Cc: Jin Yao <yao.jin@linux.intel.com>
Cc: Konstantin Khlebnikov <khlebnikov@yandex-team.ru>
Cc: Mathieu Poirier <mathieu.poirier@linaro.org>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Rasmus Villemoes <linux@rasmusvillemoes.dk>
Cc: Song Liu <songliubraving@fb.com>
Cc: Suzuki Poulouse <suzuki.poulose@arm.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Thomas Richter <tmricht@linux.ibm.com>
Cc: linux-arm-kernel@lists.infradead.org
Fixes: dd2e18e9ac20 ("perf tools: Support 'srccode' output")
Link: http://lkml.kernel.org/r/20190702103420.27540-8-leo.yan@linaro.org
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
---
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:
--
2.21.0