Re: [PATCH bpf-next v4 2/3] selftests/bpf: Add connmark read test

From: Daniel Xu <dxu@dxuuu.xyz>
To: Martin KaFai Lau <martin.lau@linux.dev>
Cc: pablo@netfilter.org, fw@strlen.de,
	netfilter-devel@vger.kernel.org, netdev@vger.kernel.org,
	linux-kernel@vger.kernel.org, andrii@kernel.org,
	daniel@iogearbox.net, ast@kernel.org, bpf@vger.kernel.org,
	memxor@gmail.com
Subject: Re: [PATCH bpf-next v4 2/3] selftests/bpf: Add connmark read test
Date: Wed, 12 Oct 2022 16:09:53 -0600	[thread overview]
Message-ID: <20221012220953.i2xevhu36kxyxscl@k2> (raw)
In-Reply-To: <43bf4a5f-dac9-4fe9-1eba-9ab9beb650aa@linux.dev>

Hi Martin,

On Tue, Oct 11, 2022 at 10:49:32PM -0700, Martin KaFai Lau wrote:
> On 8/11/22 2:55 PM, Daniel Xu wrote:
> > Test that the prog can read from the connection mark. This test is nice
> > because it ensures progs can interact with netfilter subsystem
> > correctly.
> > 
> > Signed-off-by: Daniel Xu <dxu@dxuuu.xyz>
> > Acked-by: Kumar Kartikeya Dwivedi <memxor@gmail.com>
> > ---
> >   tools/testing/selftests/bpf/prog_tests/bpf_nf.c | 3 ++-
> >   tools/testing/selftests/bpf/progs/test_bpf_nf.c | 3 +++
> >   2 files changed, 5 insertions(+), 1 deletion(-)
> > 
> > diff --git a/tools/testing/selftests/bpf/prog_tests/bpf_nf.c b/tools/testing/selftests/bpf/prog_tests/bpf_nf.c
> > index 88a2c0bdefec..544bf90ac2a7 100644
> > --- a/tools/testing/selftests/bpf/prog_tests/bpf_nf.c
> > +++ b/tools/testing/selftests/bpf/prog_tests/bpf_nf.c
> > @@ -44,7 +44,7 @@ static int connect_to_server(int srv_fd)
> >   static void test_bpf_nf_ct(int mode)
> >   {
> > -	const char *iptables = "iptables -t raw %s PREROUTING -j CT";
> > +	const char *iptables = "iptables -t raw %s PREROUTING -j CONNMARK --set-mark 42/0";
> Hi Daniel Xu, this test starts failing recently in CI [0]:
> 
> Warning: Extension CONNMARK revision 0 not supported, missing kernel module?
>   iptables v1.8.8 (nf_tables): Could not fetch rule set generation id:
> Invalid argument
> 
>   Warning: Extension CONNMARK revision 0 not supported, missing kernel module?
>   iptables v1.8.8 (nf_tables): Could not fetch rule set generation id:
> Invalid argument
> 
>   Warning: Extension CONNMARK revision 0 not supported, missing kernel module?
>   iptables v1.8.8 (nf_tables): Could not fetch rule set generation id:
> Invalid argument
> 
>   Warning: Extension CONNMARK revision 0 not supported, missing kernel module?
>   iptables v1.8.8 (nf_tables): Could not fetch rule set generation id:
> Invalid argument
> 
>   test_bpf_nf_ct:PASS:test_bpf_nf__open_and_load 0 nsec
>   test_bpf_nf_ct:FAIL:iptables unexpected error: 1024 (errno 0)
> 
> Could you help to take a look? Thanks.
> 
> [0]: https://github.com/kernel-patches/bpf/actions/runs/3231598391/jobs/5291529292

[...]

Thanks for letting me know. I took a quick look and it seems that
synproxy selftest is also failing:

    2022-10-12T03:14:20.2007627Z test_synproxy:FAIL:iptables -t raw -I PREROUTING      -i tmp1 -p tcp -m tcp --syn --dport 8080 -j CT --notrack unexpected error: 1024 (errno 2)

Googling the "Could not fetch rule set generation id" yields a lot of
hits. Most of the links are from downstream projects recommending user
downgrade iptables (nftables) to iptables-legacy.

So perhaps iptables/nftables suffered a regression somewhere. I'll take
a closer look tonight / tomorrow morning.

Thanks,
Daniel