From mboxrd@z Thu Jan 1 00:00:00 1970 From: "Michael S. Tsirkin" Subject: Re: [PATCH v2] virtio: Work around frames incorrectly marked as gso Date: Mon, 24 Feb 2020 07:46:27 -0500 Message-ID: <20200224074516-mutt-send-email-mst@kernel.org> References: <20200224101912.14074-1-anton.ivanov@cambridgegreys.com> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Return-path: Content-Disposition: inline In-Reply-To: <20200224101912.14074-1-anton.ivanov@cambridgegreys.com> Sender: netdev-owner@vger.kernel.org To: anton.ivanov@cambridgegreys.com Cc: netdev@vger.kernel.org, virtualization@lists.linux-foundation.org, linux-um@lists.infradead.org, jasowang@redhat.com, eric.dumazet@gmail.com List-Id: virtualization@lists.linuxfoundation.org On Mon, Feb 24, 2020 at 10:19:12AM +0000, anton.ivanov@cambridgegreys.com wrote: > From: Anton Ivanov > > 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 Acked-by: Michael S. Tsirkin Eric - as you looked at this in the past, would you mind acking please? > --- > 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