[PATCH 2/2] perf report: Don't add to histogram when there is no thread found

[James Clark]

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 at 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