vhost: fix error path in vhost_net_set_backend

An error could cause vhost_net_set_backend to exit without unlocking
vq->mutex. Fix this.

Signed-off-by: Jeff Dike <jdike@linux.intel.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>

1 files changed, 5 insertions, 3 deletions

diff --git a/drivers/vhost/net.c b/drivers/vhost/net.c
index ad37da2b6cb5..fcafb6b170fb 100644
--- a/drivers/vhost/net.c
+++ b/drivers/vhost/net.c
@@ -508,12 +508,12 @@ static long vhost_net_set_backend(struct vhost_net *n, unsigned index, int fd)
         /* Verify that ring has been setup correctly. */
         if (!vhost_vq_access_ok(vq)) {
                 r = -EFAULT;
-                goto err;
+                goto err_vq;
         }
         sock = get_socket(fd);
         if (IS_ERR(sock)) {
                 r = PTR_ERR(sock);
-                goto err;
+                goto err_vq;
         }
 
         /* start polling new socket */
@@ -524,12 +524,14 @@ static long vhost_net_set_backend(struct vhost_net *n, unsigned index, int fd)
         vhost_net_disable_vq(n, vq);
         rcu_assign_pointer(vq->private_data, sock);
         vhost_net_enable_vq(n, vq);
-        mutex_unlock(&vq->mutex);
 done:
         if (oldsock) {
                 vhost_net_flush_vq(n, index);
                 fput(oldsock->file);
         }
+
+err_vq:
+        mutex_unlock(&vq->mutex);
 err:
         mutex_unlock(&n->dev.mutex);
         return r;