Subject: Re: [PATCH net v2] virtio_net: fix virtnet_open and virtnet_probe competing for try_fill_recv

From: Jason Wang <[email-masked]>
Date: Thu, 26 May 2016 17:33:17 +0800

On 2016年05月26日 14:27, wangyunjian wrote:
> In function virtnet_open() and virtnet_probe(), func try_fill_recv()
> will be executed at the same time. VQ in virtqueue_add() is not protected
> well and BUG_ON will be triggered when virito_net.ko being removed.
>
> Signed-off-by: Yunjian Wang <[email-masked]>
> ---
>   drivers/net/virtio_net.c | 18 ++----------------
>   1 file changed, 2 insertions(+), 16 deletions(-)

The patch is needed for stable.

Acked-by: Jason Wang <[email-masked]>

>
> diff --git a/drivers/net/virtio_net.c b/drivers/net/virtio_net.c
> index 49d84e5..e0638e5 100644
> --- 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);
> --
> 1.7.12.4
>
>