netdev - Re: [PATCH net-next] virtio_net: set link state down when virtqueue is broken

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives
Hash Suite: Windows password security audit tool. GUI, reports in PDF.
[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]
Message-ID: <03c68dd1-a636-9d3b-1dec-5e11c8025ccc@redhat.com>
Date:   Thu, 27 May 2021 12:22:20 +0800
From:   Jason Wang <jasowang@...hat.com>
To:     wangyunjian <wangyunjian@...wei.com>, netdev@...r.kernel.org
Cc:     kuba@...nel.org, davem@...emloft.net, mst@...hat.com,
        virtualization@...ts.linux-foundation.org, dingxiaoxiong@...wei.com
Subject: Re: [PATCH net-next] virtio_net: set link state down when virtqueue
 is broken


在 2021/5/26 下午7:39, wangyunjian 写道:
> From: Yunjian Wang <wangyunjian@...wei.com>
>
> The NIC can't receive/send packets if a rx/tx virtqueue is broken.
> However, the link state of the NIC is still normal. As a result,
> the user cannot detect the NIC exception.


Doesn't we have:

        /* This should not happen! */
         if (unlikely(err)) {
                 dev->stats.tx_fifo_errors++;
                 if (net_ratelimit())
                         dev_warn(&dev->dev,
                                  "Unexpected TXQ (%d) queue failure: %d\n",
                                  qnum, err);
                 dev->stats.tx_dropped++;
                 dev_kfree_skb_any(skb);
                 return NETDEV_TX_OK;
         }

Which should be sufficient?


>
> The driver can set the link state down when the virtqueue is broken.
> If the state is down, the user can switch over to another NIC.


Note that, we probably need the watchdog for virtio-net in order to be a 
complete solution.

Thanks


>
> Signed-off-by: Yunjian Wang <wangyunjian@...wei.com>
> ---
>   drivers/net/virtio_net.c | 36 +++++++++++++++++++++++++++++++++++-
>   1 file changed, 35 insertions(+), 1 deletion(-)
>
> diff --git a/drivers/net/virtio_net.c b/drivers/net/virtio_net.c
> index 073fec4c0df1..05a3cd1c589b 100644
> --- a/drivers/net/virtio_net.c
> +++ b/drivers/net/virtio_net.c
> @@ -237,6 +237,10 @@ struct virtnet_info {
>   
>   	/* failover when STANDBY feature enabled */
>   	struct failover *failover;
> +
> +	/* Work struct for checking vq status, stop NIC if vq is broken. */
> +	struct delayed_work vq_check_work;
> +	bool broken;
>   };
>   
>   struct padded_vnet_hdr {
> @@ -1407,6 +1411,27 @@ static void refill_work(struct work_struct *work)
>   	}
>   }
>   
> +static void virnet_vq_check_work(struct work_struct *work)
> +{
> +	struct virtnet_info *vi =
> +		container_of(work, struct virtnet_info, vq_check_work.work);
> +	struct net_device *netdev = vi->dev;
> +	int i;
> +
> +	if (vi->broken)
> +		return;
> +
> +	/* If virtqueue is broken, set link down and stop all queues */
> +	for (i = 0; i < vi->max_queue_pairs; i++) {
> +		if (virtqueue_is_broken(vi->rq[i].vq) || virtqueue_is_broken(vi->sq[i].vq)) {
> +			netif_carrier_off(netdev);
> +			netif_tx_stop_all_queues(netdev);
> +			vi->broken = true;
> +			break;
> +		}
> +	}
> +}
> +
>   static int virtnet_receive(struct receive_queue *rq, int budget,
>   			   unsigned int *xdp_xmit)
>   {
> @@ -1432,6 +1457,9 @@ static int virtnet_receive(struct receive_queue *rq, int budget,
>   		}
>   	}
>   
> +	if (unlikely(!virtqueue_is_broken(rq->vq)))
> +		schedule_delayed_work(&vi->vq_check_work, HZ);
> +
>   	if (rq->vq->num_free > min((unsigned int)budget, virtqueue_get_vring_size(rq->vq)) / 2) {
>   		if (!try_fill_recv(vi, rq, GFP_ATOMIC))
>   			schedule_delayed_work(&vi->refill, 0);
> @@ -1681,6 +1709,7 @@ static netdev_tx_t start_xmit(struct sk_buff *skb, struct net_device *dev)
>   				 qnum, err);
>   		dev->stats.tx_dropped++;
>   		dev_kfree_skb_any(skb);
> +		schedule_delayed_work(&vi->vq_check_work, HZ);
>   		return NETDEV_TX_OK;
>   	}
>   
> @@ -1905,6 +1934,7 @@ static int virtnet_close(struct net_device *dev)
>   
>   	/* Make sure refill_work doesn't re-enable napi! */
>   	cancel_delayed_work_sync(&vi->refill);
> +	cancel_delayed_work_sync(&vi->vq_check_work);
>   
>   	for (i = 0; i < vi->max_queue_pairs; i++) {
>   		xdp_rxq_info_unreg(&vi->rq[i].xdp_rxq);
> @@ -2381,6 +2411,7 @@ static void virtnet_freeze_down(struct virtio_device *vdev)
>   	netif_device_detach(vi->dev);
>   	netif_tx_unlock_bh(vi->dev);
>   	cancel_delayed_work_sync(&vi->refill);
> +	cancel_delayed_work_sync(&vi->vq_check_work);
>   
>   	if (netif_running(vi->dev)) {
>   		for (i = 0; i < vi->max_queue_pairs; i++) {
> @@ -2662,7 +2693,7 @@ static void virtnet_config_changed_work(struct work_struct *work)
>   
>   	vi->status = v;
>   
> -	if (vi->status & VIRTIO_NET_S_LINK_UP) {
> +	if ((vi->status & VIRTIO_NET_S_LINK_UP) && !vi->broken) {
>   		virtnet_update_settings(vi);
>   		netif_carrier_on(vi->dev);
>   		netif_tx_wake_all_queues(vi->dev);
> @@ -2889,6 +2920,8 @@ static int virtnet_alloc_queues(struct virtnet_info *vi)
>   		goto err_rq;
>   
>   	INIT_DELAYED_WORK(&vi->refill, refill_work);
> +	INIT_DELAYED_WORK(&vi->vq_check_work, virnet_vq_check_work);
> +
>   	for (i = 0; i < vi->max_queue_pairs; i++) {
>   		vi->rq[i].pages = NULL;
>   		netif_napi_add(vi->dev, &vi->rq[i].napi, virtnet_poll,
> @@ -3240,6 +3273,7 @@ static int virtnet_probe(struct virtio_device *vdev)
>   	net_failover_destroy(vi->failover);
>   free_vqs:
>   	cancel_delayed_work_sync(&vi->refill);
> +	cancel_delayed_work_sync(&vi->vq_check_work);
>   	free_receive_page_frags(vi);
>   	virtnet_del_vqs(vi);
>   free: