Received-SPF: pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 2620:137:e000::1:20 as permitted sender) client-ip=2620:137:e000::1:20;
From:   James Clark <james.clark@arm.com>
To:     linux-perf-users@vger.kernel.org
Cc:     James Clark <james.clark@arm.com>,
        Peter Zijlstra <peterz@infradead.org>,
        Ingo Molnar <mingo@redhat.com>,
        Arnaldo Carvalho de Melo <acme@kernel.org>,
        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>,
        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>, linux-kernel@vger.kernel.org,
        coresight@lists.linaro.org, linux-arm-kernel@lists.infradead.org
Subject: [PATCH 2/2] perf report: Don't add to histogram when there is no thread found
Date:   Mon, 26 Jun 2023 17:10:58 +0100
Message-Id: <20230626161059.324046-3-james.clark@arm.com>
In-Reply-To: <20230626161059.324046-1-james.clark@arm.com>
References: <20230626161059.324046-1-james.clark@arm.com>
MIME-Version: 1.0
Content-Transfer-Encoding: 8bit
Precedence: bulk

thread__find_map() chooses to exit without assigning a thread to the
addr_location in some scenarios, for example when there are samples from
a guest and perf_guest == false. This results in a segfault when adding
to the histogram because it uses unguarded accesses to the thread member
of the addr_location.

Fix it by exiting early if no thread is set. This fixes the referenced
commit when using perf report with Coresight but probably isn't
exclusive to that case.

Fixes: 8d3031d39fe8 ("perf cs-etm: Track exception level")
Signed-off-by: James Clark <james.clark@arm.com>
---
 tools/perf/builtin-report.c | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/tools/perf/builtin-report.c b/tools/perf/builtin-report.c
index dcedfe00f04d..1a2caa4ce5c3 100644
--- a/tools/perf/builtin-report.c
+++ b/tools/perf/builtin-report.c
@@ -293,6 +293,9 @@ static int process_sample_event(struct perf_tool *tool,
 		goto out_put;
 	}
 
+	if (!al.thread)
+		goto out_put;
+
 	if (rep->stitch_lbr)
 		thread__set_lbr_stitch_enable(al.thread, true);
 
-- 
2.34.1