From mboxrd@z Thu Jan 1 00:00:00 1970 From: Jason Wang Subject: Re: [PATCH bpf-next] bpf: fix virtio-net's length calc for XDP_PASS Date: Mon, 23 Apr 2018 14:33:08 +0800 Message-ID: References: <20180423041648.2285-1-tehnerd@tehnerd.com> Mime-Version: 1.0 Content-Type: text/plain; charset=utf-8; format=flowed Content-Transfer-Encoding: 8bit Cc: netdev@vger.kernel.org, David Ahern To: "Nikita V. Shirokov" , Alexei Starovoitov , Daniel Borkmann , "Michael S. Tsirkin" Return-path: Received: from mx3-rdu2.redhat.com ([66.187.233.73]:34884 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1754024AbeDWGdP (ORCPT ); Mon, 23 Apr 2018 02:33:15 -0400 In-Reply-To: <20180423041648.2285-1-tehnerd@tehnerd.com> Content-Language: en-US Sender: netdev-owner@vger.kernel.org List-ID: On 2018年04月23日 12:16, Nikita V. Shirokov wrote: > In commit 6870de435b90 ("bpf: make virtio compatible w/ > bpf_xdp_adjust_tail") i didn't account for vi->hdr_len during new > packet's length calculation after bpf_prog_run in receive_mergeable. > because of this all packets, if they were passed to the kernel, > were truncated by 12 bytes. > > Fixes:6870de435b90 ("bpf: make virtio compatible w/ bpf_xdp_adjust_tail") > Reported-by: David Ahern > > Signed-off-by: Nikita V. Shirokov > --- > > Notes: > unfortunately it looks like that xdp_tx is still broken because > fix by Jason (introduced in "XDP_TX for virtio_net not working in recent kernel? > " thread) haven't landed yet) > > drivers/net/virtio_net.c | 2 +- > 1 file changed, 1 insertion(+), 1 deletion(-) > > diff --git a/drivers/net/virtio_net.c b/drivers/net/virtio_net.c > index 779a4f798522..08ac2cc986aa 100644 > --- a/drivers/net/virtio_net.c > +++ b/drivers/net/virtio_net.c > @@ -761,7 +761,7 @@ static struct sk_buff *receive_mergeable(struct net_device *dev, > /* recalculate len if xdp.data or xdp.data_end were > * adjusted > */ > - len = xdp.data_end - xdp.data; > + len = xdp.data_end - xdp.data + vi->hdr_len; > /* We can only create skb based on xdp_page. */ > if (unlikely(xdp_page != page)) { > rcu_read_unlock(); Acked-by: Jason Wang