Patch "vhost: use mutex_lock_nested() in vhost_dev_lock_vqs()" has been added to the 4.14-stable tree

This is a note to let you know that I've just added the patch titled

vhost: use mutex_lock_nested() in vhost_dev_lock_vqs()

to the 4.14-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary

The filename of the patch is:
vhost-use-mutex_lock_nested-in-vhost_dev_lock_vqs.patch
and it can be found in the queue-4.14 subdirectory.

If you, or anyone else, feels it should not be added to the stable tree, please let <[email protected]> know about it.

From: Jason Wang <[email protected]>
Date: Tue, 23 Jan 2018 17:27:25 +0800
Subject: vhost: use mutex_lock_nested() in vhost_dev_lock_vqs()

From: Jason Wang <[email protected]>

commit e9cb4239134c860e5f92c75bf5321bd377bb505b upstream.

We used to call mutex_lock() in vhost_dev_lock_vqs() which tries to hold mutexes of all virtqueues. This may confuse lockdep to report a possible deadlock because of trying to hold locks belong to same class. Switch to use mutex_lock_nested() to avoid false positive.

---
 drivers/vhost/vhost.c |    2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

@@ -904,7 +904,7 @@ static void vhost_dev_lock_vqs(struct vh
 {
 	int i = 0;
 	for (i = 0; i < d->nvqs; ++i)
-		mutex_lock(&d->vqs[i]->mutex);
+		mutex_lock_nested(&d->vqs[i]->mutex, i);
 }
 
 static void vhost_dev_unlock_vqs(struct vhost_dev *d)

Patches currently in stable-queue which might be from [email protected] are

queue-4.14/ptr_ring-try-vmalloc-when-kmalloc-fails.patch queue-4.14/vhost-use-mutex_lock_nested-in-vhost_dev_lock_vqs.patch queue-4.14/ptr_ring-fail-early-if-queue-occupies-more-than-kmalloc_max_size.patch