From:   Martin Rodriguez Reboredo <yakoyoku@gmail.com>
To:     miguel.ojeda.sandonis@gmail.com
Cc:     alex.gaynor@gmail.com, andrea.righi@canonical.com,
        bjorn3_gh@protonmail.com, boqun.feng@gmail.com, dxu@dxuuu.xyz,
        ecurtin@redhat.com, gary@garyguo.net, linux-kernel@vger.kernel.org,
        ojeda@kernel.org, rust-for-linux@vger.kernel.org,
        wedsonaf@gmail.com, yakoyoku@gmail.com
Subject: Re: [PATCH] rust: fix regexp in scripts/is_rust_module.sh
Date:   Mon, 13 Feb 2023 12:13:39 -0300
Message-Id: <20230213151339.661225-1-yakoyoku@gmail.com>
In-Reply-To: <'CANiq72=FZtNmYvbb-YPHmQ=bm8rH8VO3M9nemT4i03g9A2PD2Q@mail.gmail.com'>
References: <'CANiq72=FZtNmYvbb-YPHmQ=bm8rH8VO3M9nemT4i03g9A2PD2Q@mail.gmail.com'>
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On Mon, Feb 13, 2023 at 1:19 PM Miguel Ojeda <ojeda@kernel.org> wrote:=0D
> On Fri, Feb 10, 2023 at 4:26 PM Andrea Righi <andrea.righi@canonical.com>=
 wrote:=0D
> >=0D
> > nm can use "R" or "r" to show read-only data sections, but=0D
> > scripts/is_rust_module.sh can only recognize "r", so with some versions=
=0D
> > of binutils it can fail to detect if a module is a Rust module or not.=
=0D
>=0D
> Do you know which versions? If so, it would be nice to document it here.=
=0D
>=0D
> > Moreover, with this patch applied I can also relax the constraint of=0D
> > "RUST depends on !DEBUG_INFO_BTF" and build a kernel with Rust and BTF=
=0D
> > enabled at the same time (of course BTF generation is still skipped for=
=0D
> > Rust modules).=0D
>=0D
> Even if that build succeeds, can you load the modules? i.e. the=0D
> constraint was there due to=0D
> https://github.com/Rust-for-Linux/linux/issues/735.=0D
=0D
Issue was that the kernel couldn't even load C modules, Rust CUs must be=0D
skipped in vmlinux for it to work, and because of that the constraint=0D
!DEBUG_INFO_BTF || PAHOLE_HAS_LANG_EXCLUDE [1] cannot be relaxed until=0D
version 1.24+ of Pahole is the minimum requirement by the kernel. I'm OK=0D
with this change but keep in mind that it won't remedy that condition.=0D
=0D
Link: https://lore.kernel.org/bpf/20230111152050.559334-1-yakoyoku@gmail.co=
m/ [1]=0D