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

[Xianting Tian]

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@xxxxxxxxxxxxxxxxx>
> > ---
> >   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