[FIX PATCH] selftests: tracing: Fix to unmount tracefs for recovering environment

Masami Hiramatsu (Google)
2023-09-09T09:36:46Z

From: Masami Hiramatsu (Google) <mhiramat@kernel.org>

Fix to unmount the tracefs if the ftracetest mounted it for recovering
system environment. If the tracefs is already mounted, this does nothing.

Suggested-by: Mark Brown <broonie@kernel.org>
Link: https://lore.kernel.org/all/29fce076-746c-4650-8358-b4e0fa215cf7@sirena.org.uk/
Fixes: cbd965bde74c ("ftrace/selftests: Return the skip code when tracing directory not configured in kernel")
Signed-off-by: Masami Hiramatsu (Google) <mhiramat@kernel.org>
---
tools/testing/selftests/ftrace/ftracetest | 8 ++++++++
1 file changed, 8 insertions(+)

diff --git a/tools/testing/selftests/ftrace/ftracetest b/tools/testing/selftests/ftrace/ftracetest
index cb5f18c06593..89c212d82256 100755
--- a/tools/testing/selftests/ftrace/ftracetest
+++ b/tools/testing/selftests/ftrace/ftracetest
@@ -31,6 +31,9 @@ err_ret=1
# kselftest skip code is 4
err_skip=4

+# umount required
+UMOUNT_DIR=""
+
# cgroup RT scheduling prevents chrt commands from succeeding, which
# induces failures in test wakeup tests. Disable for the duration of
# the tests.
@@ -45,6 +48,9 @@ setup() {

cleanup() {
echo $sched_rt_runtime_orig > $sched_rt_runtime
+ if [ "${UMOUNT_DIR}" ]; then
+ umount ${UMOUNT_DIR} ||:
+ fi
}

errexit() { # message
@@ -160,11 +166,13 @@ if [ -z "$TRACING_DIR" ]; then
mount -t tracefs nodev /sys/kernel/tracing ||
errexit "Failed to mount /sys/kernel/tracing"
TRACING_DIR="/sys/kernel/tracing"
+ UMOUNT_DIR=${TRACING_DIR}
# If debugfs exists, then so does /sys/kernel/debug
elif [ -d "/sys/kernel/debug" ]; then
mount -t debugfs nodev /sys/kernel/debug ||
errexit "Failed to mount /sys/kernel/debug"
TRACING_DIR="/sys/kernel/debug/tracing"
+ UMOUNT_DIR=${TRACING_DIR}
else
err_ret=$err_skip
errexit "debugfs and tracefs are not configured in this kernel"