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From:   Leo Yan <leo.yan@linaro.org>
To:     Arnaldo Carvalho de Melo <acme@kernel.org>,
        Adrian Hunter <adrian.hunter@intel.com>,
        Peter Zijlstra <peterz@infradead.org>,
        Ingo Molnar <mingo@redhat.com>,
        Mark Rutland <mark.rutland@arm.com>,
        Alexander Shishkin <alexander.shishkin@linux.intel.com>,
        Jiri Olsa <jolsa@redhat.com>,
        Namhyung Kim <namhyung@kernel.org>,
        Andi Kleen <ak@linux.intel.com>,
        Tiezhu Yang <yangtiezhu@loongson.cn>,
        linux-kernel@vger.kernel.org
Cc:     Leo Yan <leo.yan@linaro.org>
Subject: [PATCH] perf auxtrace: Fix potential null pointer dereference
Date:   Tue, 20 Apr 2021 23:15:53 +0800
Message-Id: <20210420151554.2031768-1-leo.yan@linaro.org>
MIME-Version: 1.0
Content-Transfer-Encoding: 8bit
Precedence: bulk

In the function auxtrace_parse_snapshot_options(), the callback pointer
"itr->parse_snapshot_options" can be NULL if it has not been set during
the AUX record initialization.  This can cause tool crashing if the
callback pointer "itr->parse_snapshot_options" is dereferenced without
performing NULL check.

Add a NULL check for the pointer "itr->parse_snapshot_options" before
invoke the callback.

Fixes: d20031bb63dd ("perf tools: Add AUX area tracing Snapshot Mode")
Signed-off-by: Leo Yan <leo.yan@linaro.org>
---
 tools/perf/util/auxtrace.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/tools/perf/util/auxtrace.c b/tools/perf/util/auxtrace.c
index 953f4afacd3b..320b47f133d3 100644
--- a/tools/perf/util/auxtrace.c
+++ b/tools/perf/util/auxtrace.c
@@ -638,7 +638,7 @@ int auxtrace_parse_snapshot_options(struct auxtrace_record *itr,
 		break;
 	}
 
-	if (itr)
+	if (itr && itr->parse_snapshot_options)
 		return itr->parse_snapshot_options(itr, opts, str);
 
 	pr_err("No AUX area tracing to snapshot\n");
-- 
2.25.1