From: Jesper Dangaard Brouer <brouer@redhat.com>
To: Stephen Hemminger <stephen@networkplumber.org>
Cc: Brandon Cazander <brandon.cazander@multapplied.net>,
"xdp-newbies@vger.kernel.org" <xdp-newbies@vger.kernel.org>,
David Miller <davem@davemloft.net>
Subject: Re: xdpgeneric, XDP_PASS, and bpf_xdp_adjust_head decapsulation dropping packets
Date: Thu, 1 Aug 2019 16:54:33 +0200 [thread overview]
Message-ID: <20190801165408.5cac9287@carbon> (raw)
In-Reply-To: <20190801101746.702431fc@carbon>
On Thu, 1 Aug 2019 10:18:49 +0200
Jesper Dangaard Brouer <brouer@redhat.com> wrote:
[...]
> Cc. Stephen as this might be related to:
> commit 458bf2f224f0 ("net: core: support XDP generic on stacked devices.") (Author: Stephen Hemminger).
>
> On Wed, 31 Jul 2019 21:12:23 +0000 Brandon Cazander <brandon.cazander@multapplied.net> wrote:
>
> > I am having an issue with xdpgeneric specifically when using XDP_PASS after
> > bpf_xdp_adjust_head to pop some headers off. My test environment is qemu using
> > virtio_net specifically, but it also happens with e1000 in qemu/physical devices.
> >
> > On a real NIC (ixgbe), the same program is successfully passing decapsulated
> > traffic, but fails in the same way when forcing xdpgeneric mode.
>
[...]
> > Kernel is 5.2.2-1-debug, OS is openSUSE Tumbleweed 20190724.
>
> Can you test an earlier kernel, specifically before: commit
> 458bf2f224f0 ("net: core: support XDP generic on stacked devices.")
> (Author: Stephen Hemminger)
>
> $ git describe --contains 458bf2f224f04
> v5.2-rc3~26^2~11^2
>
> I fear that this commit, which moved generic-XDP to a later call point,
> might cause this. Because it could be that the SKB network_header
> update, is now done before calling XDP program (... still looking at
> code details).
I now have a reproducer myself, and I can confirm that this commit
458bf2f224f0 ("net: core: support XDP generic on stacked devices.") is
the issue... reverting it fixes the problem. (I don't have a fix yet)
--
Best regards,
Jesper Dangaard Brouer
MSc.CS, Principal Kernel Engineer at Red Hat
LinkedIn: http://www.linkedin.com/in/brouer
next prev parent reply other threads:[~2019-08-01 14:55 UTC|newest]
Thread overview: 16+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-07-31 21:12 xdpgeneric, XDP_PASS, and bpf_xdp_adjust_head decapsulation dropping packets Brandon Cazander
2019-08-01 8:18 ` Jesper Dangaard Brouer
2019-08-01 14:54 ` Jesper Dangaard Brouer [this message]
2019-08-01 16:05 ` Jesper Dangaard Brouer
2019-08-01 17:33 ` Brandon Cazander
2019-08-01 18:16 ` Jesper Dangaard Brouer
2019-08-01 18:53 ` Brandon Cazander
2019-08-01 18:00 ` [net v1 PATCH 0/4] net: fix regressions for generic-XDP Jesper Dangaard Brouer
2019-08-01 18:00 ` [net v1 PATCH 1/4] bpf: fix XDP vlan selftests test_xdp_vlan.sh Jesper Dangaard Brouer
2019-08-01 18:00 ` [net v1 PATCH 2/4] selftests/bpf: add wrapper scripts for test_xdp_vlan.sh Jesper Dangaard Brouer
2019-08-01 18:00 ` [net v1 PATCH 3/4] selftests/bpf: reduce time to execute test_xdp_vlan.sh Jesper Dangaard Brouer
2019-08-01 18:00 ` [net v1 PATCH 4/4] net: fix bpf_xdp_adjust_head regression for generic-XDP Jesper Dangaard Brouer
2019-08-02 0:44 ` Jakub Kicinski
2019-08-02 7:53 ` Jesper Dangaard Brouer
2019-08-02 17:08 ` Jakub Kicinski
2019-08-05 18:19 ` [net v1 PATCH 0/4] net: fix regressions " David Miller
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