Re: [PATCH net] virtio-net: drop NETIF_F_FRAGLIST
From: Michael S. Tsirkin
Date: Tue Aug 04 2015 - 06:05:41 EST
On Tue, Aug 04, 2015 at 05:55:45PM +0800, 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>
Acked-by: Michael S. Tsirkin <mst@xxxxxxxxxx>
Especially important now that virtio_net: add gro capability
was merged for net-next, making bridged setups create fraglists.
> ---
> 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;
>
> if (virtio_has_feature(vdev, VIRTIO_NET_F_GSO)) {
> dev->hw_features |= NETIF_F_TSO | NETIF_F_UFO
> --
> 2.1.4
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