Patch "vhost_net: add missing lock nesting notation" has been added to the 4.9-stable tree

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

vhost_net: add missing lock nesting notation

to the 4.9-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_net-add-missing-lock-nesting-notation.patch
and it can be found in the queue-4.9 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: Mon, 26 Mar 2018 16:10:23 +0800
Subject: vhost_net: add missing lock nesting notation

From: Jason Wang <[email protected]>

[ Upstream commit aaa3149bbee9ba9b4e6f0bd6e3e7d191edeae942 ]

We try to hold TX virtqueue mutex in vhost_net_rx_peek_head_len() after RX virtqueue mutex is held in handle_rx(). This requires an appropriate lock nesting notation to calm down deadlock detector.

---
 drivers/vhost/net.c |    4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

@@ -524,7 +524,7 @@ static int vhost_net_rx_peek_head_len(st
 
 	if (!len && vq->busyloop_timeout) {
 		/* Both tx vq and rx socket were polled here */
-		mutex_lock(&vq->mutex);
+		mutex_lock_nested(&vq->mutex, 1);
 		vhost_disable_notify(&net->dev, vq);
 
 		preempt_disable();

@@ -657,7 +657,7 @@ static void handle_rx(struct vhost_net *
 	struct iov_iter fixup;
 	__virtio16 num_buffers;
 
-	mutex_lock(&vq->mutex);
+	mutex_lock_nested(&vq->mutex, 0);
 	sock = vq->private_data;
 	if (!sock)
 		goto out;

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

queue-4.9/skbuff-return-emsgsize-in-skb_to_sgvec-to-prevent-overflow.patch queue-4.9/virtio_net-check-return-value-of-skb_to_sgvec-always.patch queue-4.9/vhost-validate-log-when-iotlb-is-enabled.patch queue-4.9/vhost_net-add-missing-lock-nesting-notation.patch queue-4.9/vhost-correctly-remove-wait-queue-during-poll-failure.patch queue-4.9/virtio_net-check-return-value-of-skb_to_sgvec-in-one-more-location.patch