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From:   James Clark <james.clark@arm.com>
To:     linux-perf-users@vger.kernel.org, acme@kernel.org
Cc:     James Clark <james.clark@arm.com>,
        Mathieu Poirier <mathieu.poirier@linaro.org>,
        Suzuki K Poulose <suzuki.poulose@arm.com>,
        Mike Leach <mike.leach@linaro.org>,
        Leo Yan <leo.yan@linaro.org>,
        John Garry <john.g.garry@oracle.com>,
        Will Deacon <will@kernel.org>,
        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@kernel.org>,
        Namhyung Kim <namhyung@kernel.org>,
        Ian Rogers <irogers@google.com>,
        Adrian Hunter <adrian.hunter@intel.com>,
        coresight@lists.linaro.org, linux-arm-kernel@lists.infradead.org,
        linux-kernel@vger.kernel.org
Subject: [PATCH] perf: cs-etm: Fix segfault in dso lookup
Date:   Tue, 18 Apr 2023 15:12:03 +0100
Message-Id: <20230418141203.673465-1-james.clark@arm.com>
MIME-Version: 1.0
Content-Transfer-Encoding: 8bit
Precedence: bulk

map__dso() is called before thread__find_map() which always results in a
null pointer dereference. Fix it by finding first, then checking if it
exists.

Fixes: 63df0e4bc368 ("perf map: Add accessor for dso")
Signed-off-by: James Clark <james.clark@arm.com>
---
 tools/perf/util/cs-etm.c | 6 ++++--
 1 file changed, 4 insertions(+), 2 deletions(-)

diff --git a/tools/perf/util/cs-etm.c b/tools/perf/util/cs-etm.c
index 103865968700..8dd81ddd9e4e 100644
--- a/tools/perf/util/cs-etm.c
+++ b/tools/perf/util/cs-etm.c
@@ -885,9 +885,11 @@ static u32 cs_etm__mem_access(struct cs_etm_queue *etmq, u8 trace_chan_id,
 		thread = etmq->etm->unknown_thread;
 	}
 
-	dso = map__dso(al.map);
+	if (!thread__find_map(thread, cpumode, address, &al))
+		return 0;
 
-	if (!thread__find_map(thread, cpumode, address, &al) || !dso)
+	dso = map__dso(al.map);
+	if (!dso)
 		return 0;
 
 	if (dso->data.status == DSO_DATA_STATUS_ERROR &&
-- 
2.34.1