[PATCH 3.16 176/410] vhost_net: stop device during reset owner

[Ben Hutchings]

3.16.57-rc1 review patch.  If anyone has any objections, please let me know.

------------------

From: Jason Wang <jasowang@xxxxxxxxxx>

commit 4cd879515d686849eec5f718aeac62a70b067d82 upstream.

We don't stop device before reset owner, this means we could try to
serve any virtqueue kick before reset dev->worker. This will result a
warn since the work was pending at llist during owner resetting. Fix
this by stopping device during owner reset.

Reported-by: syzbot+eb17c6162478cc50632c@xxxxxxxxxxxxxxxxxxxxxxxxx
Fixes: 3a4d5c94e9593 ("vhost_net: a kernel-level virtio server")
Signed-off-by: Jason Wang <jasowang@xxxxxxxxxx>
Signed-off-by: David S. Miller <davem@xxxxxxxxxxxxx>
[bwh: Backported to 3.16: adjust context]
Signed-off-by: Ben Hutchings <ben@xxxxxxxxxxxxxxx>
---
 drivers/vhost/net.c | 1 +
 1 file changed, 1 insertion(+)

--- a/drivers/vhost/net.c
+++ b/drivers/vhost/net.c
@@ -1009,6 +1009,7 @@ static long vhost_net_reset_owner(struct
 	}
 	vhost_net_stop(n, &tx_sock, &rx_sock);
 	vhost_net_flush(n);
+	vhost_dev_stop(&n->dev);
 	vhost_dev_reset_owner(&n->dev, memory);
 	vhost_net_vq_reset(n);
 done: