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References: <20230313215553.1045175-1-aleksander.lobakin@intel.com> <ca1385b5-b3f8-73f3-276c-a2a08ec09aa0@intel.com>
In-Reply-To: <ca1385b5-b3f8-73f3-276c-a2a08ec09aa0@intel.com>
From:   Alexei Starovoitov <alexei.starovoitov@gmail.com>
Date:   Tue, 14 Mar 2023 11:52:43 -0700
Message-ID: <CAADnVQJDz3hBEJ7kohXJ4HUZWZdbRRamfJbrZ6KUaRubBKQmfA@mail.gmail.com>
Subject: Re: [PATCH bpf-next v3 0/4] xdp: recycle Page Pool backed skbs built
 from XDP frames
To:     Alexander Lobakin <aleksander.lobakin@intel.com>
Cc:     Alexei Starovoitov <ast@kernel.org>,
        Daniel Borkmann <daniel@iogearbox.net>,
        Andrii Nakryiko <andrii@kernel.org>,
        Martin KaFai Lau <martin.lau@linux.dev>,
        Maciej Fijalkowski <maciej.fijalkowski@intel.com>,
        Larysa Zaremba <larysa.zaremba@intel.com>,
        =?UTF-8?B?VG9rZSBIw7hpbGFuZC1Kw7hyZ2Vuc2Vu?= <toke@redhat.com>,
        Song Liu <song@kernel.org>,
        Jesper Dangaard Brouer <hawk@kernel.org>,
        John Fastabend <john.fastabend@gmail.com>,
        Menglong Dong <imagedong@tencent.com>,
        Mykola Lysenko <mykolal@fb.com>,
        "David S. Miller" <davem@davemloft.net>,
        Jakub Kicinski <kuba@kernel.org>,
        Eric Dumazet <edumazet@google.com>,
        Paolo Abeni <pabeni@redhat.com>, bpf <bpf@vger.kernel.org>,
        Network Development <netdev@vger.kernel.org>,
        LKML <linux-kernel@vger.kernel.org>
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On Tue, Mar 14, 2023 at 4:58=E2=80=AFAM Alexander Lobakin
<aleksander.lobakin@intel.com> wrote:
>
>   All error logs:
>   libbpf: prog 'trace_virtqueue_add_sgs': BPF program load failed: Bad
> address
>   libbpf: prog 'trace_virtqueue_add_sgs': -- BEGIN PROG LOAD LOG --
>   The sequence of 8193 jumps is too complex.
>   verification time 77808 usec
>   stack depth 64
>   processed 156616 insns (limit 1000000) max_states_per_insn 8
> total_states 1754 peak_states 1712 mark_read 12
>   -- END PROG LOAD LOG --
>   libbpf: prog 'trace_virtqueue_add_sgs': failed to load: -14
>   libbpf: failed to load object 'loop6.bpf.o'
>   scale_test:FAIL:expect_success unexpected error: -14 (errno 14)
>   #257     verif_scale_loop6:FAIL
>   Summary: 288/1766 PASSED, 21 SKIPPED, 1 FAILED
>
> So, xdp_do_redirect, which was previously failing, now works fine. OTOH,
> "verif_scale_loop6" now fails, but from what I understand from the log,
> it has nothing with the series ("8193 jumps is too complex" -- I don't
> even touch program-related stuff). I don't know what's the reason of it
> failing, can it be some CI issues or maybe some recent commits?

Yeah. It's an issue with the latest clang.
We don't have a workaround for this yet.
It's not a blocker for your patchset.
We didn't have time to look at it closely.