Re: [PATCH net] virtio-net: drop NETIF_F_FRAGLIST

[Jason Wang]

On 08/04/2015 07:11 PM, Sergei Shtylyov wrote:
> Hello.
>
> On 8/4/2015 12:55 PM, Jason Wang wrote:
>
>> virtio declares support for NETIF_F_FRAGLIST, but assumes
>> that there are at most MAX_SKB_FRAGS + 2 fragments which isn't
>> always true with a fraglist.
>
>> A longer fraglist in the skb will make the call to skb_to_sgvec overflow
>> the sg array, leading to memory corruption.
>
>> Drop NETIF_F_FRAGLIST so we only get what we can handle.
>
>> Cc: Michael S. Tsirkin <mst@xxxxxxxxxx>
>> Signed-off-by: Jason Wang <jasowang@xxxxxxxxxx>
>> ---
>> The patch is needed for stable.
>> ---
>>   drivers/net/virtio_net.c | 4 ++--
>>   1 file changed, 2 insertions(+), 2 deletions(-)
>
>> diff --git a/drivers/net/virtio_net.c b/drivers/net/virtio_net.c
>> index 7fbca37..2347a73 100644
>> --- a/drivers/net/virtio_net.c
>> +++ b/drivers/net/virtio_net.c
>> @@ -1756,9 +1756,9 @@ static int virtnet_probe(struct virtio_device
>> *vdev)
>>       /* Do we support "hardware" checksums? */
>>       if (virtio_has_feature(vdev, VIRTIO_NET_F_CSUM)) {
>>           /* This opens up the world of extra features. */
>> -        dev->hw_features |=
>> NETIF_F_HW_CSUM|NETIF_F_SG|NETIF_F_FRAGLIST;
>> +        dev->hw_features |= NETIF_F_HW_CSUM|NETIF_F_SG;
>>           if (csum)
>> -            dev->features |=
>> NETIF_F_HW_CSUM|NETIF_F_SG|NETIF_F_FRAGLIST;
>> +            dev->features |= NETIF_F_HW_CSUM|NETIF_F_SG;
>
>    I'd have added spaces around | to match the style seen below.
>

Ok, will fix this in V2.

>>           if (virtio_has_feature(vdev, VIRTIO_NET_F_GSO)) {
>>               dev->hw_features |= NETIF_F_TSO | NETIF_F_UFO
>
> MBR, Sergei
>

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