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From:   Alexei Starovoitov <alexei.starovoitov@gmail.com>
Date:   Thu, 30 Apr 2020 22:15:51 -0700
Message-ID: <CAADnVQKymMnEs0jFg8-qZLXS5n0DxMrqhmwQ17Do=TKd+niqhw@mail.gmail.com>
Subject: Re: BPFilter: bit size mismatch between bpfiter_umh and vmliux
To:     Masahiro Yamada <masahiroy@kernel.org>
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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On Thu, Apr 30, 2020 at 9:06 PM Masahiro Yamada <masahiroy@kernel.org> wrote:
>
> 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.

thank you.
I saw the patches, but didn't have time to test or comment on them.
To be fair umh logic was bit rotting a bit, but that will change soon.