[PATCH] locking/mutex: clear MUTEX_FLAGS if wait_list is empty due to signal

From: qiang.zhang@windriver.com
To: peterz@infradead.org, mingo@redhat.com, will@kernel.org,
	longman@redhat.com, boqun.feng@gmail.com
Cc: linux-kernel@vger.kernel.org
Subject: [PATCH] locking/mutex: clear MUTEX_FLAGS if wait_list is empty due to signal
Date: Sat, 15 May 2021 10:30:10 +0800	[thread overview]
Message-ID: <20210515023010.102985-1-qiang.zhang@windriver.com> (raw)

From: Zqiang <qiang.zhang@windriver.com>

Clear MUTEX_FLAGS when call mutex_lock_interruptible()
interrupted by a signal and the lock->wait_list is empty.

Signed-off-by: Zqiang <qiang.zhang@windriver.com>
---
 kernel/locking/mutex.c | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/kernel/locking/mutex.c b/kernel/locking/mutex.c
index cb6b112ce155..4ac354ca092b 100644
--- a/kernel/locking/mutex.c
+++ b/kernel/locking/mutex.c
@@ -1081,6 +1081,8 @@ __mutex_lock_common(struct mutex *lock, long state, unsigned int subclass,
 err:
 	__set_current_state(TASK_RUNNING);
 	mutex_remove_waiter(lock, &waiter, current);
+	if (likely(list_empty(&lock->wait_list)))
+		__mutex_clear_flag(lock, MUTEX_FLAGS);
 err_early_kill:
 	spin_unlock(&lock->wait_lock);
 	debug_mutex_free_waiter(&waiter);
-- 
2.25.1

