[net,4/4] virito-net: fix leaking page for gso packet during mergeable XDP
diff mbox series

Message ID 1526891706-18516-5-git-send-email-jasowang@redhat.com
State New, archived
Headers show
Series
  • Fix several issues of virtio-net mergeable XDP
Related show

Commit Message

Jason Wang May 21, 2018, 8:35 a.m. UTC
We need to drop refcnt to xdp_page if we see a gso packet. Otherwise
it will be leaked. Fixing this by moving the check of gso packet above
the linearizing logic.

Cc: John Fastabend <john.fastabend@gmail.com>
Fixes: 72979a6c3590 ("virtio_net: xdp, add slowpath case for non contiguous buffers")
Signed-off-by: Jason Wang <jasowang@redhat.com>
---
 drivers/net/virtio_net.c | 16 ++++++++--------
 1 file changed, 8 insertions(+), 8 deletions(-)

Comments

Michael S. Tsirkin May 21, 2018, 3:01 p.m. UTC | #1
On Mon, May 21, 2018 at 04:35:06PM +0800, Jason Wang wrote:
> We need to drop refcnt to xdp_page if we see a gso packet. Otherwise
> it will be leaked. Fixing this by moving the check of gso packet above
> the linearizing logic.
> 
> Cc: John Fastabend <john.fastabend@gmail.com>
> Fixes: 72979a6c3590 ("virtio_net: xdp, add slowpath case for non contiguous buffers")
> Signed-off-by: Jason Wang <jasowang@redhat.com>

typo in subject

> ---
>  drivers/net/virtio_net.c | 16 ++++++++--------
>  1 file changed, 8 insertions(+), 8 deletions(-)
> 
> diff --git a/drivers/net/virtio_net.c b/drivers/net/virtio_net.c
> index 165a922..f8db809 100644
> --- a/drivers/net/virtio_net.c
> +++ b/drivers/net/virtio_net.c
> @@ -707,6 +707,14 @@ static struct sk_buff *receive_mergeable(struct net_device *dev,
>  		void *data;
>  		u32 act;
>  
> +		/* Transient failure which in theory could occur if
> +		 * in-flight packets from before XDP was enabled reach
> +		 * the receive path after XDP is loaded. In practice I
> +		 * was not able to create this condition.

BTW we should probably drop the last sentence. It says in theory, should be enough.

> +		 */
> +		if (unlikely(hdr->hdr.gso_type))
> +			goto err_xdp;
> +
>  		/* This happens when rx buffer size is underestimated
>  		 * or headroom is not enough because of the buffer
>  		 * was refilled before XDP is set. This should only
> @@ -728,14 +736,6 @@ static struct sk_buff *receive_mergeable(struct net_device *dev,
>  			xdp_page = page;
>  		}
>  
> -		/* Transient failure which in theory could occur if
> -		 * in-flight packets from before XDP was enabled reach
> -		 * the receive path after XDP is loaded. In practice I
> -		 * was not able to create this condition.
> -		 */
> -		if (unlikely(hdr->hdr.gso_type))
> -			goto err_xdp;
> -
>  		/* Allow consuming headroom but reserve enough space to push
>  		 * the descriptor on if we get an XDP_TX return code.
>  		 */
> -- 
> 2.7.4
Jason Wang May 22, 2018, 3:37 a.m. UTC | #2
On 2018年05月21日 23:01, Michael S. Tsirkin wrote:
> On Mon, May 21, 2018 at 04:35:06PM +0800, Jason Wang wrote:
>> We need to drop refcnt to xdp_page if we see a gso packet. Otherwise
>> it will be leaked. Fixing this by moving the check of gso packet above
>> the linearizing logic.
>>
>> Cc: John Fastabend <john.fastabend@gmail.com>
>> Fixes: 72979a6c3590 ("virtio_net: xdp, add slowpath case for non contiguous buffers")
>> Signed-off-by: Jason Wang <jasowang@redhat.com>
> typo in subject

Let me fix it in V2.

>> ---
>>   drivers/net/virtio_net.c | 16 ++++++++--------
>>   1 file changed, 8 insertions(+), 8 deletions(-)
>>
>> diff --git a/drivers/net/virtio_net.c b/drivers/net/virtio_net.c
>> index 165a922..f8db809 100644
>> --- a/drivers/net/virtio_net.c
>> +++ b/drivers/net/virtio_net.c
>> @@ -707,6 +707,14 @@ static struct sk_buff *receive_mergeable(struct net_device *dev,
>>   		void *data;
>>   		u32 act;
>>   
>> +		/* Transient failure which in theory could occur if
>> +		 * in-flight packets from before XDP was enabled reach
>> +		 * the receive path after XDP is loaded. In practice I
>> +		 * was not able to create this condition.
> BTW we should probably drop the last sentence. It says in theory, should be enough.

Ok.

Thanks

>> +		 */
>> +		if (unlikely(hdr->hdr.gso_type))
>> +			goto err_xdp;
>> +
>>   		/* This happens when rx buffer size is underestimated
>>   		 * or headroom is not enough because of the buffer
>>   		 * was refilled before XDP is set. This should only
>> @@ -728,14 +736,6 @@ static struct sk_buff *receive_mergeable(struct net_device *dev,
>>   			xdp_page = page;
>>   		}
>>   
>> -		/* Transient failure which in theory could occur if
>> -		 * in-flight packets from before XDP was enabled reach
>> -		 * the receive path after XDP is loaded. In practice I
>> -		 * was not able to create this condition.
>> -		 */
>> -		if (unlikely(hdr->hdr.gso_type))
>> -			goto err_xdp;
>> -
>>   		/* Allow consuming headroom but reserve enough space to push
>>   		 * the descriptor on if we get an XDP_TX return code.
>>   		 */
>> -- 
>> 2.7.4

Patch
diff mbox series

diff --git a/drivers/net/virtio_net.c b/drivers/net/virtio_net.c
index 165a922..f8db809 100644
--- a/drivers/net/virtio_net.c
+++ b/drivers/net/virtio_net.c
@@ -707,6 +707,14 @@  static struct sk_buff *receive_mergeable(struct net_device *dev,
 		void *data;
 		u32 act;
 
+		/* Transient failure which in theory could occur if
+		 * in-flight packets from before XDP was enabled reach
+		 * the receive path after XDP is loaded. In practice I
+		 * was not able to create this condition.
+		 */
+		if (unlikely(hdr->hdr.gso_type))
+			goto err_xdp;
+
 		/* This happens when rx buffer size is underestimated
 		 * or headroom is not enough because of the buffer
 		 * was refilled before XDP is set. This should only
@@ -728,14 +736,6 @@  static struct sk_buff *receive_mergeable(struct net_device *dev,
 			xdp_page = page;
 		}
 
-		/* Transient failure which in theory could occur if
-		 * in-flight packets from before XDP was enabled reach
-		 * the receive path after XDP is loaded. In practice I
-		 * was not able to create this condition.
-		 */
-		if (unlikely(hdr->hdr.gso_type))
-			goto err_xdp;
-
 		/* Allow consuming headroom but reserve enough space to push
 		 * the descriptor on if we get an XDP_TX return code.
 		 */