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

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Message-Id: <20190709183126.30257-7-acme@kernel.org>
Date:   Tue,  9 Jul 2019 15:31:07 -0300
From:   Arnaldo Carvalho de Melo <acme@...nel.org>
To:     Ingo Molnar <mingo@...nel.org>,
        Thomas Gleixner <tglx@...utronix.de>
Cc:     Jiri Olsa <jolsa@...nel.org>, Namhyung Kim <namhyung@...nel.org>,
        Clark Williams <williams@...hat.com>,
        linux-kernel@...r.kernel.org, linux-perf-users@...r.kernel.org,
        Leo Yan <leo.yan@...aro.org>,
        Adrian Hunter <adrian.hunter@...el.com>,
        Alexander Shishkin <alexander.shishkin@...ux.intel.com>,
        Alexey Budankov <alexey.budankov@...ux.intel.com>,
        Alexios Zavras <alexios.zavras@...el.com>,
        Andi Kleen <ak@...ux.intel.com>,
        Changbin Du <changbin.du@...el.com>,
        "David S . Miller" <davem@...emloft.net>,
        Davidlohr Bueso <dave@...olabs.net>,
        Eric Saint-Etienne <eric.saint.etienne@...cle.com>,
        Jin Yao <yao.jin@...ux.intel.com>,
        Konstantin Khlebnikov <khlebnikov@...dex-team.ru>,
        Mathieu Poirier <mathieu.poirier@...aro.org>,
        Peter Zijlstra <peterz@...radead.org>,
        Rasmus Villemoes <linux@...musvillemoes.dk>,
        Song Liu <songliubraving@...com>,
        Suzuki Poulouse <suzuki.poulose@....com>,
        Thomas Richter <tmricht@...ux.ibm.com>,
        linux-arm-kernel@...ts.infradead.org,
        Arnaldo Carvalho de Melo <acme@...hat.com>
Subject: [PATCH 06/25] perf map: Fix potential NULL pointer dereference found by smatch tool

From: Leo Yan <leo.yan@...aro.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@...aro.org>
Acked-by: Jiri Olsa <jolsa@...nel.org>
Cc: Adrian Hunter <adrian.hunter@...el.com>
Cc: Alexander Shishkin <alexander.shishkin@...ux.intel.com>
Cc: Alexey Budankov <alexey.budankov@...ux.intel.com>
Cc: Alexios Zavras <alexios.zavras@...el.com>
Cc: Andi Kleen <ak@...ux.intel.com>
Cc: Changbin Du <changbin.du@...el.com>
Cc: David S. Miller <davem@...emloft.net>
Cc: Davidlohr Bueso <dave@...olabs.net>
Cc: Eric Saint-Etienne <eric.saint.etienne@...cle.com>
Cc: Jin Yao <yao.jin@...ux.intel.com>
Cc: Konstantin Khlebnikov <khlebnikov@...dex-team.ru>
Cc: Mathieu Poirier <mathieu.poirier@...aro.org>
Cc: Namhyung Kim <namhyung@...nel.org>
Cc: Peter Zijlstra <peterz@...radead.org>
Cc: Rasmus Villemoes <linux@...musvillemoes.dk>
Cc: Song Liu <songliubraving@...com>
Cc: Suzuki Poulouse <suzuki.poulose@....com>
Cc: Thomas Gleixner <tglx@...utronix.de>
Cc: Thomas Richter <tmricht@...ux.ibm.com>
Cc: linux-arm-kernel@...ts.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@...hat.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