Hi > -----Original Message----- > From: Yunsheng Lin <linyunsheng@xxxxxxxxxx> > Sent: Thursday, March 9, 2023 6:53 PM > To: Angus Chen <angus.chen@xxxxxxxxxxxxxxx>; mst@xxxxxxxxxx; > jasowang@xxxxxxxxxx; davem@xxxxxxxxxxxxx; edumazet@xxxxxxxxxx; > kuba@xxxxxxxxxx; pabeni@xxxxxxxxxx; ast@xxxxxxxxxx; daniel@xxxxxxxxxxxxx; > hawk@xxxxxxxxxx; john.fastabend@xxxxxxxxx > Cc: virtualization@xxxxxxxxxxxxxxxxxxxxxxxxxx; netdev@xxxxxxxxxxxxxxx; > linux-kernel@xxxxxxxxxxxxxxx; bpf@xxxxxxxxxxxxxxx; Xuan Zhuo > <xuanzhuo@xxxxxxxxxxxxxxxxx> > Subject: Re: [PATCH] virtio_net: Use NETDEV_TX_BUSY when has no buf to send > > On 2023/3/9 15:49, Angus Chen wrote: > > Don't consume skb if virtqueue_add return -ENOSPC. > > Is this fixing the same out of space problem caused by > xdp xmit as Xuan Zhuo is fixing, or it is fixing a different > case? Yes, the same print info. > > https://lore.kernel.org/netdev/20230308071921-mutt-send-email-mst@kernel. > org/T/#mc4c5766a59fb8be988bb6a4dfa48f49e58df3ea6 > En,I haven't noticed this patch before. > > > > Signed-off-by: Angus Chen <angus.chen@xxxxxxxxxxxxxxx> > > --- > > drivers/net/virtio_net.c | 2 +- > > 1 file changed, 1 insertion(+), 1 deletion(-) > > > > diff --git a/drivers/net/virtio_net.c b/drivers/net/virtio_net.c > > index fb5e68ed3ec2..4096ea3d2eb6 100644 > > --- a/drivers/net/virtio_net.c > > +++ b/drivers/net/virtio_net.c > > @@ -1980,7 +1980,7 @@ 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); > > Returning NETDEV_TX_BUSY will caused stack to requeue the skb > and send it again when space is available, but you have freed the skb here, > isn't this cause use-after-free problem? Yes，you are right, would be crash after I tested more times .I will drop it,thank you. > > > - return NETDEV_TX_OK; > > + return (err == -ENOSPC) ? NETDEV_TX_BUSY : NETDEV_TX_OK; > > } > > > > /* Don't wait up for transmitted skbs to be freed. */ > >
