vhost-net: update used ring on backend change

On backend change, we flushed out outstanding skbs but forgot to update the used ring, so that done entries were left in the ubuf_info ring. As a result we lose heads or complete incorrect ones, crashing the guest or leaking memory. Fix by updating the used ring. Signed-off-by: Michael S. Tsirkin <[email protected]>
chewitt · Jul 21, 2011 · c047e5f · c047e5f
1 parent b834226
commit c047e5f
Showing 1 changed file with 5 additions and 1 deletion.
diff --git a/drivers/vhost/net.c b/drivers/vhost/net.c
@@ -711,8 +711,12 @@ static long vhost_net_set_backend(struct vhost_net *n, unsigned index, int fd)
 
 	mutex_unlock(&vq->mutex);
 
-	if (oldubufs)
+	if (oldubufs) {
 		vhost_ubuf_put_and_wait(oldubufs);
+		mutex_lock(&vq->mutex);
+		vhost_zerocopy_signal_used(vq);
+		mutex_unlock(&vq->mutex);
+	}
 
 	if (oldsock) {
 		vhost_net_flush_vq(n, index);