| Message ID | 20230309074952.975-1-angus.chen@jaguarmicro.com (mailing list archive) |
|---|---|
| State | Changes Requested |
| Delegated to: | Netdev Maintainers |
| Headers | show |
| Series | virtio_net: Use NETDEV_TX_BUSY when has no buf to send | expand |
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? https://lore.kernel.org/netdev/20230308071921-mutt-send-email-mst@kernel.org/T/#mc4c5766a59fb8be988bb6a4dfa48f49e58df3ea6 > > Signed-off-by: Angus Chen <angus.chen@jaguarmicro.com> > --- > 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? > - return NETDEV_TX_OK; > + return (err == -ENOSPC) ? NETDEV_TX_BUSY : NETDEV_TX_OK; > } > > /* Don't wait up for transmitted skbs to be freed. */ >
Hi > -----Original Message----- > From: Yunsheng Lin <linyunsheng@huawei.com> > Sent: Thursday, March 9, 2023 6:53 PM > To: Angus Chen <angus.chen@jaguarmicro.com>; mst@redhat.com; > jasowang@redhat.com; davem@davemloft.net; edumazet@google.com; > kuba@kernel.org; pabeni@redhat.com; ast@kernel.org; daniel@iogearbox.net; > hawk@kernel.org; john.fastabend@gmail.com > Cc: virtualization@lists.linux-foundation.org; netdev@vger.kernel.org; > linux-kernel@vger.kernel.org; bpf@vger.kernel.org; Xuan Zhuo > <xuanzhuo@linux.alibaba.com> > 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@jaguarmicro.com> > > --- > > 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. */ > >
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); - return NETDEV_TX_OK; + return (err == -ENOSPC) ? NETDEV_TX_BUSY : NETDEV_TX_OK; } /* Don't wait up for transmitted skbs to be freed. */
Don't consume skb if virtqueue_add return -ENOSPC. Signed-off-by: Angus Chen <angus.chen@jaguarmicro.com> --- drivers/net/virtio_net.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)