[tip:smp/hotplug] perf/core: Don't release cred_guard_mutex if not taken

[tip-bot for Alexander Levin]

Commit-ID:  e5aeee51f6b4fb22e851105ee6d8ad211c40a214
Gitweb:     http://git.kernel.org/tip/e5aeee51f6b4fb22e851105ee6d8ad211c40a214
Author:     Alexander Levin <alexander.levin@xxxxxxxxxxx>
AuthorDate: Sat, 3 Jun 2017 03:39:13 +0000
Committer:  Thomas Gleixner <tglx@xxxxxxxxxxxxx>
CommitDate: Sat, 3 Jun 2017 09:28:45 +0200

perf/core: Don't release cred_guard_mutex if not taken

If we failed to acquire task's cred_guard_mutex we shouldn't proceed
to release it in the error path.

Fixes: a63fbed776c ("perf/tracing/cpuhotplug: Fix locking order")
Signed-off-by: Alexander Levin <alexander.levin@xxxxxxxxxxx>
Cc: peterz@xxxxxxxxxxxxx
Cc: rostedt@xxxxxxxxxxx
Cc: mathieu.desnoyers@xxxxxxxxxxxx
Cc: mhiramat@xxxxxxxxxx
Cc: paulmck@xxxxxxxxxxxxxxxxxx
Cc: bigeasy@xxxxxxxxxxxxx
Link: http://lkml.kernel.org/r/20170603033903.12056-1-alexander.levin@xxxxxxxxxxx
Signed-off-by: Thomas Gleixner <tglx@xxxxxxxxxxxxx>

---
 kernel/events/core.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/kernel/events/core.c b/kernel/events/core.c
index b97cda4..1f1b8cd 100644
--- a/kernel/events/core.c
+++ b/kernel/events/core.c
@@ -9878,7 +9878,7 @@ SYSCALL_DEFINE5(perf_event_open,
 	if (task) {
 		err = mutex_lock_interruptible(&task->signal->cred_guard_mutex);
 		if (err)
-			goto err_cred;
+			goto err_task;
 
 		/*
 		 * Reuse ptrace permission checks for now.