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From:   Zhouyi Zhou <zhouzhouyi@gmail.com>
Date:   Sat, 20 May 2023 07:37:43 +0800
Message-ID: <CAABZP2yjONcZNVKT88JXq_QyVzuDnu12nD8APT0XJ45dOtSFrQ@mail.gmail.com>
Subject: Re: a small question about bpftool struct_ops
To:     Martin KaFai Lau <martin.lau@linux.dev>
Cc:     bpf@vger.kernel.org, linux-kernel <linux-kernel@vger.kernel.org>
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Thank you for responding so quickly ;-)

On Sat, May 20, 2023 at 3:01=E2=80=AFAM Martin KaFai Lau <martin.lau@linux.=
dev> wrote:
>
> On 5/19/23 5:07 AM, Zhouyi Zhou wrote:
> > Dear developers:
> > I compiled bpftool and bpf tests in mainline (2d1bcbc6cd70),
> > but when I invoke:
> > bpftool struct_ops register bpf_cubic.bpf.o
> >
> > the command line fail with:
> > libbpf: struct_ops init_kern: struct tcp_congestion_ops data is not
> > found in struct bpf_struct_ops_tcp_congestion_ops
>
> At the machine trying to register the bpf_cubic, please dump the vmlinux =
btf and
> search for bpf_struct_ops_tcp_congestion_ops and paste it here:
>
> For example:
> #> bpftool btf dump file /sys/kernel/btf/vmlinux
>
> ...
>
> [74578] STRUCT 'bpf_struct_ops_tcp_congestion_ops' size=3D256 vlen=3D3
>          'refcnt' type_id=3D145 bits_offset=3D0
>          'state' type_id=3D74569 bits_offset=3D32
>          'data' type_id=3D6241 bits_offset=3D512
OK
[214398] STRUCT 'bpf_struct_ops_tcp_congestion_ops' size=3D256 vlen=3D3
        'refcnt' type_id=3D298 bits_offset=3D0
        'state' type_id=3D214224 bits_offset=3D32
        'data' type_id=3D213704 bits_offset=3D512

Please tell me if I could provide any further information.

You are of great help

Thank you very much
Zhouyi
>