selftests: tracing: Fix to unmount tracefs for recovering environment

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>
Reviewed-by: Steven Rostedt (Google) <rostedt@goodmis.org>
Reviewed-by: Mark Brown <broonie@kernel.org>
Signed-off-by: Shuah Khan <skhan@linuxfoundation.org>

diff --git a/tools/testing/selftests/ftrace/ftracetest b/tools/testing/selftests/ftrace/ftracetest
index 7df8baa..c778d4d 100755 (executable)
--- 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 > $sched_rt_runtime
+  if [ -n "${UMOUNT_DIR}" ]; then
+    umount ${UMOUNT_DIR} ||:
+  fi
 }
 
 errexit() { # message
@@ -161,11 +167,13 @@ 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"