In test_record_concurrent, as stderr is sent to /dev/null, error
messages are hidden. Change this to gather the error messages and dump
them on failure.

Some minor sh->bash changes to add some more diagnostics in
trap_cleanup.

Signed-off-by: Ian Rogers <irogers@google.com>
---
 tools/perf/tests/shell/lock_contention.sh | 9 +++++++--
 1 file changed, 7 insertions(+), 2 deletions(-)

diff --git a/tools/perf/tests/shell/lock_contention.sh b/tools/perf/tests/shell/lock_contention.sh
index c1ec5762215b..43c2438f6153 100755
--- a/tools/perf/tests/shell/lock_contention.sh
+++ b/tools/perf/tests/shell/lock_contention.sh
@@ -1,4 +1,4 @@
-#!/bin/sh
+#!/bin/bash
 # kernel lock contention analysis test
 # SPDX-License-Identifier: GPL-2.0
 
@@ -7,14 +7,17 @@ set -e
 err=0
 perfdata=$(mktemp /tmp/__perf_test.perf.data.XXXXX)
 result=$(mktemp /tmp/__perf_test.result.XXXXX)
+errout=$(mktemp /tmp/__perf_test.errout.XXXXX)
 
 cleanup() {
 	rm -f ${perfdata}
 	rm -f ${result}
+	rm -f ${errout}
 	trap - EXIT TERM INT
 }
 
 trap_cleanup() {
+	echo "Unexpected signal in ${FUNCNAME[1]}"
 	cleanup
 	exit ${err}
 }
@@ -75,10 +78,12 @@ test_bpf()
 test_record_concurrent()
 {
 	echo "Testing perf lock record and perf lock contention at the same time"
-	perf lock record -o- -- perf bench sched messaging 2> /dev/null | \
+	perf lock record -o- -- perf bench sched messaging 2> ${errout} | \
 	perf lock contention -i- -E 1 -q 2> ${result}
 	if [ "$(cat "${result}" | wc -l)" != "1" ]; then
 		echo "[Fail] Recorded result count is not 1:" "$(cat "${result}" | wc -l)"
+		cat ${errout}
+		cat ${result}
 		err=1
 		exit
 	fi
-- 
2.47.1.613.gc27f4b7a9f-goog