> On Nov 25, 2025, at 12:57 PM, Paolo Abeni <[email protected]> wrote: > > CC netdev
Thats odd, I used git send-email --to-cmd='./scripts/get_maintainer.pl, but it looks like in MAINTAINERS, that only would have hit VIRTIO CORE AND NET DRIVERS, which does not include netdev@ Should that have ? L: [email protected] <mailto:[email protected]> Said another way, should all changes to include/linux/virtio_net.h be cc’d to netdev DL? I suspect the answer is yes, I’ll send a patch for that in the interest of not having this issue again :) > > On 11/25/25 6:51 PM, Jon Kohler wrote: >> Commit a2fb4bc4e2a6 ("net: implement virtio helpers to handle UDP >> GSO tunneling.") inadvertently altered checksum offload behavior >> for guests not using UDP GSO tunneling. >> >> Before, tun_put_user called tun_vnet_hdr_from_skb, which passed >> has_data_valid = true to virtio_net_hdr_from_skb. >> >> After, tun_put_user began calling tun_vnet_hdr_tnl_from_skb instead, >> which passes has_data_valid = false into both call sites. >> >> This caused virtio hdr flags to not include VIRTIO_NET_HDR_F_DATA_VALID >> for SKBs where skb->ip_summed == CHECKSUM_UNNECESSARY. As a result, >> guests are forced to recalculate checksums unnecessarily. >> >> Restore the previous behavior by ensuring has_data_valid = true is >> passed in the !tnl_gso_type case. >> >> Cc: Paolo Abeni <[email protected]> >> Fixes: a2fb4bc4e2a6 ("net: implement virtio helpers to handle UDP GSO >> tunneling.") >> Signed-off-by: Jon Kohler <[email protected]> >> --- >> include/linux/virtio_net.h | 2 +- >> 1 file changed, 1 insertion(+), 1 deletion(-) >> >> diff --git a/include/linux/virtio_net.h b/include/linux/virtio_net.h >> index b673c31569f3..570c6dd1666d 100644 >> --- a/include/linux/virtio_net.h >> +++ b/include/linux/virtio_net.h >> @@ -394,7 +394,7 @@ virtio_net_hdr_tnl_from_skb(const struct sk_buff *skb, >> tnl_gso_type = skb_shinfo(skb)->gso_type & (SKB_GSO_UDP_TUNNEL | >> SKB_GSO_UDP_TUNNEL_CSUM); >> if (!tnl_gso_type) >> - return virtio_net_hdr_from_skb(skb, hdr, little_endian, false, >> + return virtio_net_hdr_from_skb(skb, hdr, little_endian, true, >> vlan_hlen); >> >> /* Tunnel support not negotiated but skb ask for it. */ > > virtio_net_hdr_tnl_from_skb() is used also by the virtio_net driver, > which in turn must not use VIRTIO_NET_HDR_F_DATA_VALID on tx. Ah! Good eye, I’ll see what trouble I can get into and send a v2 > > I think you need to add another argument to > virtio_net_hdr_tnl_from_skb(), or possibly implement a separate helper > to take care of csum offload - the symmetric of > virtio_net_handle_csum_offload(). > > Also you need to CC netdev, otherwise the patch will not be processed by > patchwork. > > /P No problems on cc’ing netdev, just didn’t realize this one header didn’t auto cc the list. Will keep an eye on that, and happy to send a patch to MAINTAINERS file for discussion.
