Re: [PATCH bpf-next v5 11/11] selftests/bpf: add test cases for redirection between udp and unix

From: Andrii Nakryiko <andrii.nakryiko@gmail.com>
To: Cong Wang <xiyou.wangcong@gmail.com>
Cc: Networking <netdev@vger.kernel.org>, bpf <bpf@vger.kernel.org>,
	Cong Wang <cong.wang@bytedance.com>,
	John Fastabend <john.fastabend@gmail.com>,
	Daniel Borkmann <daniel@iogearbox.net>,
	Jakub Sitnicki <jakub@cloudflare.com>,
	Lorenz Bauer <lmb@cloudflare.com>
Subject: Re: [PATCH bpf-next v5 11/11] selftests/bpf: add test cases for redirection between udp and unix
Date: Thu, 5 Aug 2021 15:43:33 -0700	[thread overview]
Message-ID: <CAEf4BzaccTCGeONN4MB5iRBZfmzfS3rR0R6XEPVmUKukrLSJ3w@mail.gmail.com> (raw)
In-Reply-To: <20210704190252.11866-12-xiyou.wangcong@gmail.com>

On Sun, Jul 4, 2021 at 12:05 PM Cong Wang <xiyou.wangcong@gmail.com> wrote:
>
> From: Cong Wang <cong.wang@bytedance.com>
>
> Add two test cases to ensure redirection between udp and unix
> work bidirectionally.
>
> Cc: John Fastabend <john.fastabend@gmail.com>
> Cc: Daniel Borkmann <daniel@iogearbox.net>
> Cc: Jakub Sitnicki <jakub@cloudflare.com>
> Cc: Lorenz Bauer <lmb@cloudflare.com>
> Signed-off-by: Cong Wang <cong.wang@bytedance.com>
> ---
>  .../selftests/bpf/prog_tests/sockmap_listen.c | 170 ++++++++++++++++++
>  1 file changed, 170 insertions(+)
>

[...]

> +       n = write(c1, "a", 1);
> +       if (n < 0)
> +               FAIL_ERRNO("%s: write", log_prefix);
> +       if (n == 0)
> +               FAIL("%s: incomplete write", log_prefix);
> +       if (n < 1)
> +               goto close;
> +
> +       key = SK_PASS;
> +       err = xbpf_map_lookup_elem(verd_mapfd, &key, &pass);
> +       if (err)
> +               goto close;
> +       if (pass != 1)
> +               FAIL("%s: want pass count 1, have %d", log_prefix, pass);
> +
> +       n = read(mode == REDIR_INGRESS ? p0 : c0, &b, 1);
> +       if (n < 0)
> +               FAIL_ERRNO("%s: read", log_prefix);

Hey Cong,

This test is pretty flaky and quite frequently fails in our CIs (e.g., [0]):

./test_progs-no_alu32:unix_udp_redir_to_connected:1949: egress: read:
Resource temporarily unavailable
  unix_udp_redir_to_connected:FAIL:1949

Please send a fix to make it more reliable. Thanks!

  [0] https://github.com/anakryiko/libbpf/runs/3249152533?check_suite_focus=true

> +       if (n == 0)
> +               FAIL("%s: incomplete read", log_prefix);
> +
> +close:
> +       xclose(c1);
> +       xclose(p1);
> +close_cli0:
> +       xclose(c0);
> +       xclose(p0);
> +
> +}
> +

[...]