virtio_net: fix virtnet_open and virtnet_probe competing for try_fill_recv

In function virtnet_open() and virtnet_probe(), func try_fill_recv() may
be executed at the same time. VQ in virtqueue_add() has not been protected
well and BUG_ON will be triggered when virito_net.ko being removed.

Signed-off-by: Yunjian Wang <wangyunjian@huawei.com>
Acked-by: Jason Wang <jasowang@redhat.com>
Acked-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

diff --git a/drivers/net/virtio_net.c b/drivers/net/virtio_net.c
index 49d84e5..e0638e5 100644 (file)
--- a/drivers/net/virtio_net.c
+++ b/drivers/net/virtio_net.c
@@ -1925,24 +1925,11 @@ static int virtnet_probe(struct virtio_device *vdev)
 
        virtio_device_ready(vdev);
 
-       /* Last of all, set up some receive buffers. */
-       for (i = 0; i < vi->curr_queue_pairs; i++) {
-               try_fill_recv(vi, &vi->rq[i], GFP_KERNEL);
-
-               /* If we didn't even get one input buffer, we're useless. */
-               if (vi->rq[i].vq->num_free ==
-                   virtqueue_get_vring_size(vi->rq[i].vq)) {
-                       free_unused_bufs(vi);
-                       err = -ENOMEM;
-                       goto free_recv_bufs;
-               }
-       }
-
        vi->nb.notifier_call = &virtnet_cpu_callback;
        err = register_hotcpu_notifier(&vi->nb);
        if (err) {
                pr_debug("virtio_net: registering cpu notifier failed\n");
-               goto free_recv_bufs;
+               goto free_unregister_netdev;
        }
 
        /* Assume link up if device can't report link status,
@@ -1960,10 +1947,9 @@ static int virtnet_probe(struct virtio_device *vdev)
 
        return 0;
 
-free_recv_bufs:
+free_unregister_netdev:
        vi->vdev->config->reset(vdev);
 
-       free_receive_bufs(vi);
        unregister_netdev(dev);
 free_vqs:
        cancel_delayed_work_sync(&vi->refill);