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Date:   Wed, 23 Feb 2022 12:34:24 +0800
From:   Shung-Hsi Yu <shung-hsi.yu@suse.com>
To:     Connor O'Brien <connoro@google.com>
CC:     Alexei Starovoitov <ast@kernel.org>,
        Daniel Borkmann <daniel@iogearbox.net>,
        Andrii Nakryiko <andrii@kernel.org>,
        Martin KaFai Lau <kafai@fb.com>,
        Song Liu <songliubraving@fb.com>, Yonghong Song <yhs@fb.com>,
        John Fastabend <john.fastabend@gmail.com>,
        KP Singh <kpsingh@kernel.org>, netdev@vger.kernel.org,
        bpf@vger.kernel.org, linux-kernel@vger.kernel.org,
        Michal =?utf-8?B?U3VjaMOhbmVr?= <msuchanek@suse.de>
Subject: Re: [PATCH bpf-next] bpf: add config to allow loading modules with
 BTF mismatches
Message-ID: <YhW5UIQ5kf8Fr3kI@syu-laptop.lan>
References: <20220223012814.1898677-1-connoro@google.com>
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On Wed, Feb 23, 2022 at 01:28:14AM +0000, Connor O'Brien wrote:
> BTF mismatch can occur for a separately-built module even when the ABI
> is otherwise compatible and nothing else would prevent successfully
> loading. Add a new config to control how mismatches are handled. By
> default, preserve the current behavior of refusing to load the
> module. If MODULE_ALLOW_BTF_MISMATCH is enabled, load the module but
> ignore its BTF information.
>=20
> Suggested-by: Yonghong Song <yhs@fb.com>
> Suggested-by: Michal Such=C3=A1nek <msuchanek@suse.de>
> Signed-off-by: Connor O'Brien <connoro@google.com>

Maybe reference the discussion thread as well?

Link: https://lore.kernel.org/bpf/CAADnVQJ+OVPnBz8z3vNu8gKXX42jCUqfuvhWAyCQ=
Du8N_yqqwQ@mail.gmail.com/

Otherwise

Acked-by: Shung-Hsi Yu <shung-hsi.yu@suse.com>

> ---
> Hello,
>=20
> In the discussion regarding BTF compatibility & modules, there seemed
> to be broad agreement that an option to ignore mismatches would be
> reasonable. Currently the only option for handling this problem seems
> to be to disable BTF entirely, so this would at least be an
> incremental improvement.
>=20
> Thanks,
> Connor