[PATCH RT 12/32] posix-timers: Unlock expiry lock in the early return

[Steven Rostedt]

4.19.94-rt39-rc1 stable review patch.
If anyone has any objections, please let me know.

------------------

From: Sebastian Andrzej Siewior <bigeasy@xxxxxxxxxxxxx>

[ Upstream commit 356a2781375ec58521a9bc3f500488745990c242 ]

Patch ("posix-timers: Add expiry lock") acquired a lock in
run_posix_cpu_timers() but didn't drop the lock in the early return.

Unlock the lock in the early return path.

Reported-by: kbuild test robot <lkp@xxxxxxxxx>
Reported-by: Dan Carpenter <dan.carpenter@xxxxxxxxxx>
Reviewed-by: Thomas Gleixner <tglx@xxxxxxxxxxxxx>
Signed-off-by: Sebastian Andrzej Siewior <bigeasy@xxxxxxxxxxxxx>
Signed-off-by: Steven Rostedt (VMware) <rostedt@xxxxxxxxxxx>
---
 kernel/time/posix-cpu-timers.c | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/kernel/time/posix-cpu-timers.c b/kernel/time/posix-cpu-timers.c
index 765e700962ab..c9964dc3276b 100644
--- a/kernel/time/posix-cpu-timers.c
+++ b/kernel/time/posix-cpu-timers.c
@@ -1175,8 +1175,10 @@ static void __run_posix_cpu_timers(struct task_struct *tsk)
 	expiry_lock = this_cpu_ptr(&cpu_timer_expiry_lock);
 	spin_lock(expiry_lock);
 
-	if (!lock_task_sighand(tsk, &flags))
+	if (!lock_task_sighand(tsk, &flags)) {
+		spin_unlock(expiry_lock);
 		return;
+	}
 	/*
 	 * Here we take off tsk->signal->cpu_timers[N] and
 	 * tsk->cpu_timers[N] all the timers that are firing, and
-- 
2.24.1