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From:   Masahiro Yamada <masahiroy@kernel.org>
Date:   Fri, 1 May 2020 13:05:51 +0900
Message-ID: <CAK7LNAQ5NMZWrQ_1yk+_-06zrmYMOcKvNnuX=u1sReuy6wg9Gw@mail.gmail.com>
Subject: Re: BPFilter: bit size mismatch between bpfiter_umh and vmliux
To:     Alexei Starovoitov <alexei.starovoitov@gmail.com>
Cc:     Alexei Starovoitov <ast@kernel.org>, bpf <bpf@vger.kernel.org>,
        Networking <netdev@vger.kernel.org>,
        Daniel Borkmann <daniel@iogearbox.net>,
        Martin KaFai Lau <kafai@fb.com>,
        Linux Kernel Mailing List <linux-kernel@vger.kernel.org>
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Hi Alexei,

On Wed, Apr 29, 2020 at 1:14 AM Alexei Starovoitov
<alexei.starovoitov@gmail.com> wrote:
> >
> > At least, the build was successful,
> > but does this work at runtime?
> >
> > If this is a bug, I can fix it cleanly.
> >
> > I think the bit size of the user mode helper
> > should match to the kernel bit size. Is this correct?
>
> yes. they should match.
> In theory we can have -m32 umh running on 64-bit kernel,
> but I wouldn't bother adding support for such thing
> until there is a use case.
> Running 64-bit umh on 32-bit kernel is no go.


Thanks for the comments.


This issue will be fixed by this:
https://patchwork.kernel.org/patch/11515997/

and the Makefile will be cleaned up by this:
https://patchwork.kernel.org/patch/11515995/


They are parts of the big series of Makefile cleanups.
So, I will apply the whole to kbuild tree.

Thanks.

--
Best Regards
Masahiro Yamada