tracing/ftrace: add missing unlock in register_stat_tracer()

We should unlock all_stat_sessions_mutex before returning failure.

Signed-off-by: Li Zefan <lizf@cn.fujitsu.com>
Signed-off-by: Steven Rostedt <srostedt@redhat.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>

1 files changed, 3 insertions, 1 deletions

diff --git a/kernel/trace/trace_stat.c b/kernel/trace/trace_stat.c
index cb29282b9485..2110cea2ece3 100644
--- a/kernel/trace/trace_stat.c
+++ b/kernel/trace/trace_stat.c
@@ -73,8 +73,10 @@ int register_stat_tracer(struct tracer_stat *trace)
         /* Already registered? */
         mutex_lock(&all_stat_sessions_mutex);
         list_for_each_entry_safe(node, tmp, &all_stat_sessions, session_list) {
-                if (node->ts == trace)
+                if (node->ts == trace) {
+                        mutex_unlock(&all_stat_sessions_mutex);
                         return -EINVAL;
+                }
         }
         mutex_unlock(&all_stat_sessions_mutex);