Subject: futex: Use pi_state_update_owner() in put_pi_state()
From: Thomas Gleixner <tglx@linutronix.de>
Date: Wed Jan 20 11:35:19 2021 +0100
Git-commit: 6ccc84f917d33312eb2846bd7b567639f585ad6d
Patch-mainline: v5.11-rc6
References: bsc#1181349 bsc#1149032 CVE-2021-3347

No point in open coding it. This way it gains the extra sanity checks.

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: stable@vger.kernel.org
Signed-off-by: Davidlohr Bueso <dbueso@suse.de>

---
 kernel/futex.c |    8 +-------
 1 file changed, 1 insertion(+), 7 deletions(-)

--- a/kernel/futex.c
+++ b/kernel/futex.c
@@ -884,16 +884,10 @@ static void put_pi_state(struct futex_pi
 	 * and has cleaned up the pi_state already
 	 */
 	if (pi_state->owner) {
-		struct task_struct *owner;
 		unsigned long flags;
 
 		raw_spin_lock_irqsave(&pi_state->pi_mutex.wait_lock, flags);
-		owner = pi_state->owner;
-		if (owner) {
-			raw_spin_lock(&owner->pi_lock);
-			list_del_init(&pi_state->list);
-			raw_spin_unlock(&owner->pi_lock);
-		}
+		pi_state_update_owner(pi_state, NULL);
 		rt_mutex_proxy_unlock(&pi_state->pi_mutex);
 		raw_spin_unlock_irqrestore(&pi_state->pi_mutex.wait_lock, flags);
 	}