From: Willem de Bruijn <willemb@google.com> stable inclusion from linux-4.19.223 commit 5fefa884a55bd5995e77f4fdd89f0400f42b39f7 -------------------------------- [ Upstream commit 1ed1d592113959f00cc552c3b9f47ca2d157768f ] virtio_net_hdr_set_proto infers skb->protocol from the virtio_net_hdr gso_type, to avoid packets getting dropped for lack of a proto type. Its protocol choice is a guess, especially in the case of UFO, where the single VIRTIO_NET_HDR_GSO_UDP label covers both UFOv4 and UFOv6. Skip this best effort if the field is already initialized. Whether explicitly from userspace, or implicitly based on an earlier call to dev_parse_header_protocol (which is more robust, but was introduced after this patch). Fixes: 9d2f67e43b73 ("net/packet: fix packet drop as of virtio gso") Signed-off-by: Willem de Bruijn <willemb@google.com> Link: https://lore.kernel.org/r/20211220145027.2784293-1-willemdebruijn.kernel@gma... Signed-off-by: Jakub Kicinski <kuba@kernel.org> Signed-off-by: Sasha Levin <sashal@kernel.org> Signed-off-by: Yongqiang Liu <liuyongqiang13@huawei.com> Signed-off-by: Laibin Qiu <qiulaibin@huawei.com> --- include/linux/virtio_net.h | 3 +++ 1 file changed, 3 insertions(+) diff --git a/include/linux/virtio_net.h b/include/linux/virtio_net.h index 3e2ee7739c11..a7c197299fc7 100644 --- a/include/linux/virtio_net.h +++ b/include/linux/virtio_net.h @@ -10,6 +10,9 @@ static inline int virtio_net_hdr_set_proto(struct sk_buff *skb, const struct virtio_net_hdr *hdr) { + if (skb->protocol) + return 0; + switch (hdr->gso_type & ~VIRTIO_NET_HDR_GSO_ECN) { case VIRTIO_NET_HDR_GSO_TCPV4: case VIRTIO_NET_HDR_GSO_UDP: -- 2.22.0