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Tsirkin" Cc: davem@davemloft.net, kuba@kernel.org, virtualization@lists.linux-foundation.org, netdev@vger.kernel.org, linux-kernel@vger.kernel.org References: <20210518055336-mutt-send-email-mst@kernel.org> <4aaf5125-ce75-c72a-4b4a-11c91cb85a72@linux.alibaba.com> From: Jason Wang Message-ID: <72f284c6-b2f5-a395-a68f-afe801eb81be@redhat.com> Date: Tue, 25 May 2021 14:19:03 +0800 User-Agent: Mozilla/5.0 (Macintosh; Intel Mac OS X 10.15; rv:78.0) Gecko/20100101 Thunderbird/78.10.2 MIME-Version: 1.0 In-Reply-To: <4aaf5125-ce75-c72a-4b4a-11c91cb85a72@linux.alibaba.com> Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 8bit Content-Language: en-US Precedence: bulk List-ID: X-Mailing-List: netdev@vger.kernel.org 在 2021/5/19 下午10:18, Xianting Tian 写道: > 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(). So you don't explain why you need to remove BUG(). I think it deserve a BUG(). >>> >>> Signed-off-by: Xianting Tian >>> --- >>>   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? I think not if I was not wrong. Each sources (either userspace or device), the skb should be built through virtio_net_hdr_to_skb() which means the validation has already been done. If we it fails here, it's a real bug. Thanks >> >> don't we want at least a WARN_ON? Or _ONCE? >> >>>       if (vi->mergeable_rx_bufs) >>>           hdr->num_buffers = 0; >>> -- >>> 2.17.1 >