Re: [PATCH] virtio_net: Remove BUG() to aviod machine dead

Xianting Tian
2021-05-19T14:18:55Z

thanks, I submit the patch as commented by Andrew
https://lkml.org/lkml/2021/5/18/256

Actually, if xmit_skb() returns error, below code will give a warning
with error code.

/* Try to transmit */
err = xmit_skb(sq, skb);

/* 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;
}

在 2021/5/18 下午5:54, Michael S. Tsirkin 写道:
> typo in subject
>
> On Tue, May 18, 2021 at 05:46:56PM +0800, Xianting Tian wrote:
>> When met error, we output a print to avoid a BUG().
>>
>> Signed-off-by: Xianting Tian <xianting.tian@linux.alibaba.com>
>> ---
>> drivers/net/virtio_net.c | 5 ++---
>> 1 file changed, 2 insertions(+), 3 deletions(-)
>>
>> diff --git a/drivers/net/virtio_net.c b/drivers/net/virtio_net.c
>> index c921ebf3ae82..a66174d13e81 100644
>> --- a/drivers/net/virtio_net.c
>> +++ b/drivers/net/virtio_net.c
>> @@ -1647,9 +1647,8 @@ static int xmit_skb(struct send_queue *sq, struct
>> sk_buff *skb)
>> hdr = skb_vnet_hdr(skb);
>>
>> if (virtio_net_hdr_from_skb(skb, &hdr->hdr,
>> - virtio_is_little_endian(vi->vdev), false,
>> - 0))
>> - BUG();
>> + virtio_is_little_endian(vi->vdev), false, 0))
>> + return -EPROTO;
>>
>
> why EPROTO? can you add some comments to explain what is going on pls?
>
> is this related to a malicious hypervisor thing?
>
> don't we want at least a WARN_ON? Or _ONCE?
>
>> if (vi->mergeable_rx_bufs)
>> hdr->num_buffers = 0;
>> --
>> 2.17.1