From mboxrd@z Thu Jan 1 00:00:00 1970 From: "Nikita V. Shirokov" Subject: [PATCH bpf-next] bpf: fix virtio-net's length calc for XDP_PASS Date: Sun, 22 Apr 2018 21:16:48 -0700 Message-ID: <20180423041648.2285-1-tehnerd@tehnerd.com> Cc: netdev@vger.kernel.org, David Ahern , "Nikita V. Shirokov" To: Alexei Starovoitov , Daniel Borkmann , "Michael S. Tsirkin" , Jason Wang Return-path: Received: from mail-pf0-f194.google.com ([209.85.192.194]:45201 "EHLO mail-pf0-f194.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750736AbeDWERM (ORCPT ); Mon, 23 Apr 2018 00:17:12 -0400 Received: by mail-pf0-f194.google.com with SMTP id l27so8146713pfk.12 for ; Sun, 22 Apr 2018 21:17:12 -0700 (PDT) Sender: netdev-owner@vger.kernel.org List-ID: 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(); -- 2.15.1