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

在 2021/6/2 下午1:59, Leon Romanovsky 写道:

On Tue, May 25, 2021 at 02:19:03PM +0800, Jason Wang wrote:

quoted

在 2021/5/19 下午10:18, Xianting Tian 写道:

quoted

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:

quoted

typo in subject

On Tue, May 18, 2021 at 05:46:56PM +0800, Xianting Tian wrote:

quoted

When met error, we output a print to avoid a BUG().

So you don't explain why you need to remove BUG(). I think it deserve a
BUG().

BUG() will crash the machine and virtio_net is not kernel core
functionality that must stop the machine to prevent anything truly
harmful and basic.

Note that the BUG() here is not for virtio-net itself. It tells us that a bug was found by virtio-net.

That is, the one that produces the skb has a bug, usually it's the network core.

There could also be the issue of the packet from untrusted source (userspace like TAP or packet socket) but they should be validated there.

Thanks

I would argue that code in drivers/* shouldn't call BUG() macros at all.

If it is impossible, don't check for that or add WARN_ON() and recover,
but don't crash whole system.

Thanks

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