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From:   Neal Gompa <neal@gompa.dev>
Date:   Wed, 11 Jan 2023 11:21:16 -0500
Message-ID: <CAEg-Je-Auc4u5OzJWL7VmFKLn3ASN1DAMFTfFkge4ddwZ7RJmg@mail.gmail.com>
Subject: Re: [PATCH v3] scripts: Exclude Rust CUs with pahole
To:     Eric Curtin <ecurtin@redhat.com>
Cc:     Martin Rodriguez Reboredo <yakoyoku@gmail.com>,
        linux-kernel@vger.kernel.org,
        Arnaldo Carvalho de Melo <acme@kernel.org>,
        bpf@vger.kernel.org, rust-for-linux@vger.kernel.org,
        Alexei Starovoitov <ast@kernel.org>,
        Daniel Borkmann <daniel@iogearbox.net>,
        Andrii Nakryiko <andrii@kernel.org>,
        Jiri Olsa <jolsa@kernel.org>, Yonghong Song <yhs@fb.com>,
        Miguel Ojeda <miguel.ojeda.sandonis@gmail.com>
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On Wed, Jan 11, 2023 at 11:16 AM Eric Curtin <ecurtin@redhat.com> wrote:
>
> On Wed, 11 Jan 2023 at 15:34, Neal Gompa <neal@gompa.dev> wrote:
> >
> > On Wed, Jan 11, 2023 at 10:21 AM Martin Rodriguez Reboredo
> > <yakoyoku@gmail.com> wrote:
> > >
> > > Version 1.24 of pahole has the capability to exclude compilation units
> > > (CUs) of specific languages [1] [2]. Rust, as of writing, is not
> > > currently supported by pahole and if it's used with a build that has
> > > BTF debugging enabled it results in malformed kernel and module
> > > binaries [3]. So it's better for pahole to exclude Rust CUs until
> > > support for it arrives.
> > >
> > > Link: https://git.kernel.org/pub/scm/devel/pahole/pahole.git/commit/?id=49358dfe2aaae4e90b072332c3e324019826783f [1]
> > > Link: https://git.kernel.org/pub/scm/devel/pahole/pahole.git/commit/?id=8ee363790b7437283c53090a85a9fec2f0b0fbc4 [2]
> > > Link: https://github.com/Rust-for-Linux/linux/issues/735 [3]
> > >
> > > Co-developed-by: Eric Curtin <ecurtin@redhat.com>
> > > Signed-off-by: Eric Curtin <ecurtin@redhat.com>
> > > Signed-off-by: Martin Rodriguez Reboredo <yakoyoku@gmail.com>
> > > ---
> > > V2 -> V3: Enable pahole option upon comparing with version 1.24
> > > V1 -> V2: Removed dependency on auto.conf
> > >
> > >  init/Kconfig            | 2 +-
> > >  lib/Kconfig.debug       | 9 +++++++++
> > >  scripts/pahole-flags.sh | 4 ++++
> > >  3 files changed, 14 insertions(+), 1 deletion(-)
> > >
> > > diff --git a/init/Kconfig b/init/Kconfig
> > > index 694f7c160c9c..360aef8d7292 100644
> > > --- a/init/Kconfig
> > > +++ b/init/Kconfig
> > > @@ -1913,7 +1913,7 @@ config RUST
> > >         depends on !MODVERSIONS
> > >         depends on !GCC_PLUGINS
> > >         depends on !RANDSTRUCT
> > > -       depends on !DEBUG_INFO_BTF
> > > +       depends on !DEBUG_INFO_BTF || PAHOLE_HAS_LANG_EXCLUDE
> >
> > Does the order matter here? I'd rather it prefer a fixed pahole and
> > disable BTF only if we can't use pahole properly.
>
> The order won't matter.
>

Then it looks good to me!

Reviewed-by: Neal Gompa <neal@gompa.dev>


-- 
真実はいつも一つ！/ Always, there's only one truth!