Re: [PATCH v2] virtio: Work around frames incorrectly marked as gso
flat view
From: "Michael S. Tsirkin" <mst@redhat.com>
Date: 2020-02-24 12:46:37
Also in:
linux-um, virtualization
On Mon, Feb 24, 2020 at 10:19:12AM +0000, anton.ivanov@cambridgegreys.com wrote:
From: Anton Ivanov <anton.ivanov@cambridgegreys.com> Some of the locally generated frames marked as GSO which arrive at virtio_net_hdr_from_skb() have no GSO_TYPE, no fragments (data_len = 0) and length significantly shorter than the MTU (752 in my experiments). This is observed on raw sockets reading off vEth interfaces in all 4.x and 5.x kernels I tested.
A bit more info on how to reproduce couldn't hurt here.
These frames are reported as invalid while they are in fact gso-less frames. This patch marks the vnet header as no-GSO for them instead of reporting it as invalid. Signed-off-by: Anton Ivanov <anton.ivanov@cambridgegreys.com>
Acked-by: Michael S. Tsirkin <mst@redhat.com> Eric - as you looked at this in the past, would you mind acking please?
quoted hunk ↗ jump to hunk
--- include/linux/virtio_net.h | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-)diff --git a/include/linux/virtio_net.h b/include/linux/virtio_net.h index 0d1fe9297ac6..94fb78c3a2ab 100644 --- a/include/linux/virtio_net.h +++ b/include/linux/virtio_net.h@@ -100,8 +100,8 @@ static inline int virtio_net_hdr_from_skb(const struct sk_buff *skb, { memset(hdr, 0, sizeof(*hdr)); /* no info leak */ - if (skb_is_gso(skb)) { - struct skb_shared_info *sinfo = skb_shinfo(skb); + struct skb_shared_info *sinfo = skb_shinfo(skb); + if (skb_is_gso(skb) && sinfo->gso_type) { /* This is a hint as to how much should be linear. */ hdr->hdr_len = __cpu_to_virtio16(little_endian,-- 2.20.1