linux-kernel - [PATCH AUTOSEL 6.14 15/30] ksmbd: fix WARNING "do not call blocking ops when !TASK

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Message-Id: <20250422021550.1940809-15-sashal@kernel.org>
Date: Mon, 21 Apr 2025 22:15:35 -0400
From: Sasha Levin <sashal@...nel.org>
To: linux-kernel@...r.kernel.org,
	stable@...r.kernel.org
Cc: Namjae Jeon <linkinjeon@...nel.org>,
	Steve French <stfrench@...rosoft.com>,
	Sasha Levin <sashal@...nel.org>,
	smfrench@...il.com,
	linux-cifs@...r.kernel.org
Subject: [PATCH AUTOSEL 6.14 15/30] ksmbd: fix WARNING "do not call blocking ops when !TASK_RUNNING"

From: Namjae Jeon <linkinjeon@...nel.org>

[ Upstream commit 1df0d4c616138784e033ad337961b6e1a6bcd999 ]

wait_event_timeout() will set the state of the current
task to TASK_UNINTERRUPTIBLE, before doing the condition check. This
means that ksmbd_durable_scavenger_alive() will try to acquire the mutex
while already in a sleeping state. The scheduler warns us by giving
the following warning:

do not call blocking ops when !TASK_RUNNING; state=2 set at
 [<0000000061515a6f>] prepare_to_wait_event+0x9f/0x6c0
WARNING: CPU: 2 PID: 4147 at kernel/sched/core.c:10099 __might_sleep+0x12f/0x160

mutex lock is not needed in ksmbd_durable_scavenger_alive().

Signed-off-by: Namjae Jeon <linkinjeon@...nel.org>
Signed-off-by: Steve French <stfrench@...rosoft.com>
Signed-off-by: Sasha Levin <sashal@...nel.org>
---
 fs/smb/server/vfs_cache.c | 8 +-------
 1 file changed, 1 insertion(+), 7 deletions(-)

diff --git a/fs/smb/server/vfs_cache.c b/fs/smb/server/vfs_cache.c
index 8d1f30dcba7e8..1f8fa3468173a 100644
--- a/fs/smb/server/vfs_cache.c
+++ b/fs/smb/server/vfs_cache.c
@@ -713,12 +713,8 @@ static bool tree_conn_fd_check(struct ksmbd_tree_connect *tcon,
 
 static bool ksmbd_durable_scavenger_alive(void)
 {
-	mutex_lock(&durable_scavenger_lock);
-	if (!durable_scavenger_running) {
-		mutex_unlock(&durable_scavenger_lock);
+	if (!durable_scavenger_running)
 		return false;
-	}
-	mutex_unlock(&durable_scavenger_lock);
 
 	if (kthread_should_stop())
 		return false;
@@ -799,9 +795,7 @@ static int ksmbd_durable_scavenger(void *dummy)
 			break;
 	}
 
-	mutex_lock(&durable_scavenger_lock);
 	durable_scavenger_running = false;
-	mutex_unlock(&durable_scavenger_lock);
 
 	module_put(THIS_MODULE);
 
-- 
2.39.5