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From:   Jakub Sitnicki <jakub@cloudflare.com>
To:     Yan Zhai <yan@cloudflare.com>
Cc:     bpf@vger.kernel.org, Alexei Starovoitov <ast@kernel.org>,
        Daniel Borkmann <daniel@iogearbox.net>,
        Andrii Nakryiko <andrii@kernel.org>,
        Martin KaFai Lau <martin.lau@linux.dev>,
        Song Liu <song@kernel.org>, Yonghong Song <yhs@fb.com>,
        John Fastabend <john.fastabend@gmail.com>,
        KP Singh <kpsingh@kernel.org>,
        Stanislav Fomichev <sdf@google.com>,
        Hao Luo <haoluo@google.com>, Jiri Olsa <jolsa@kernel.org>,
        "David S. Miller" <davem@davemloft.net>,
        Eric Dumazet <edumazet@google.com>,
        Jakub Kicinski <kuba@kernel.org>,
        Paolo Abeni <pabeni@redhat.com>,
        Mykola Lysenko <mykolal@fb.com>, Shuah Khan <shuah@kernel.org>,
        linux-kernel@vger.kernel.org, netdev@vger.kernel.org,
        linux-kselftest@vger.kernel.org,
        Jordan Griege <jgriege@cloudflare.com>,
        kernel-team@cloudflare.com
Subject: Re: [PATCH v3 bpf 0/2] bpf: return proper error codes for lwt redirect
Date:   Tue, 25 Jul 2023 15:20:06 +0200
In-reply-to: <cover.1690255889.git.yan@cloudflare.com>
Message-ID: <87mszkxh3c.fsf@cloudflare.com>
MIME-Version: 1.0
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On Mon, Jul 24, 2023 at 09:12 PM -07, Yan Zhai wrote:
> lwt xmit hook does not expect positive return values in function
> ip_finish_output2 and ip6_finish_output2. However, BPF redirect programs
> can return positive values such like NET_XMIT_DROP, NET_RX_DROP, and etc
> as errors. Such return values can panic the kernel unexpectedly:
>
> https://gist.github.com/zhaiyan920/8fbac245b261fe316a7ef04c9b1eba48
>
> This patch fixes the return values from BPF redirect, so the error
> handling would be consistent at xmit hook. It also adds a few test cases
> to prevent future regressions.
>
> v2: https://lore.kernel.org/netdev/ZLdY6JkWRccunvu0@debian.debian/ 
> v1: https://lore.kernel.org/bpf/ZLbYdpWC8zt9EJtq@debian.debian/
>
> changes since v2:
>   * subject name changed
>   * also covered redirect to ingress case
>   * added selftests
>
> changes since v1:
>   * minor code style changes
>
> Yan Zhai (2):
>   bpf: fix skb_do_redirect return values
>   bpf: selftests: add lwt redirect regression test cases
>
>  net/core/filter.c                             |  12 +-
>  tools/testing/selftests/bpf/Makefile          |   1 +
>  .../selftests/bpf/progs/test_lwt_redirect.c   |  67 +++++++
>  .../selftests/bpf/test_lwt_redirect.sh        | 165 ++++++++++++++++++
>  4 files changed, 244 insertions(+), 1 deletion(-)
>  create mode 100644 tools/testing/selftests/bpf/progs/test_lwt_redirect.c
>  create mode 100755 tools/testing/selftests/bpf/test_lwt_redirect.sh

For the series:

Tested-by: Jakub Sitnicki <jakub@cloudflare.com>