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From:   Zhouyi Zhou <zhouzhouyi@gmail.com>
Date:   Sun, 21 May 2023 16:27:56 +0800
Message-ID: <CAABZP2zvn_rfC=E9FF-7Hmruq69gEnZJ5aW8mSbOPQijveeKcA@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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Hi

On Sat, May 20, 2023 at 7:37=E2=80=AFAM Zhouyi Zhou <zhouzhouyi@gmail.com> =
wrote:
>
> Thank you for responding so quickly ;-)
>
> On Sat, May 20, 2023 at 3:01=E2=80=AFAM Martin KaFai Lau <martin.lau@linu=
x.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 vmlinu=
x 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
Thanks for your help

Or, can you teach me how to prepare an environment that can run
"bpftool struct_ops register xxx.o" ;-)
(A few words of description of OS version (Ubuntu/CentOS/Suse for etc)
and example kernel .config is enough)

I am an enthusiastic learner ;-)

Thanks in advance
Zhouyi
> >