Re: [PATCH] kbuild: rust: avoid creating temporary files

From: Masahiro Yamada <masahiroy@kernel.org>
To: Miguel Ojeda <ojeda@kernel.org>
Cc: "Wedson Almeida Filho" <wedsonaf@gmail.com>,
	"Alex Gaynor" <alex.gaynor@gmail.com>,
	"Nathan Chancellor" <nathan@kernel.org>,
	"Nick Desaulniers" <ndesaulniers@google.com>,
	"Nicolas Schier" <nicolas@fjasle.eu>,
	"Boqun Feng" <boqun.feng@gmail.com>,
	"Gary Guo" <gary@garyguo.net>,
	"Björn Roy Baron" <bjorn3_gh@protonmail.com>,
	"Benno Lossin" <benno.lossin@proton.me>,
	"Alice Ryhl" <aliceryhl@google.com>,
	"Andreas Hindborg" <a.hindborg@samsung.com>,
	linux-kbuild@vger.kernel.org, rust-for-linux@vger.kernel.org,
	linux-kernel@vger.kernel.org, patches@lists.linux.dev,
	"Raphael Nestler" <raphael.nestler@gmail.com>,
	"Andrea Righi" <andrea.righi@canonical.com>,
	stable@vger.kernel.org
Subject: Re: [PATCH] kbuild: rust: avoid creating temporary files
Date: Fri, 21 Jul 2023 02:17:55 +0900	[thread overview]
Message-ID: <CAK7LNAQ-hjW_19fjA+E-bQCrXcVPdN4-GvzAnEnYzna5KRVXew@mail.gmail.com> (raw)
In-Reply-To: <20230718055235.1050223-1-ojeda@kernel.org>

On Tue, Jul 18, 2023 at 2:52 PM Miguel Ojeda <ojeda@kernel.org> wrote:
>
> `rustc` outputs by default the temporary files (i.e. the ones saved
> by `-Csave-temps`, such as `*.rcgu*` files) in the current working
> directory when `-o` and `--out-dir` are not given (even if
> `--emit=x=path` is given, i.e. it does not use those for temporaries).
>
> Since out-of-tree modules are compiled from the `linux` tree,
> `rustc` then tries to create them there, which may not be accessible.
>
> Thus pass `--out-dir` explicitly, even if it is just for the temporary
> files.
>
> Reported-by: Raphael Nestler <raphael.nestler@gmail.com>
> Closes: https://github.com/Rust-for-Linux/linux/issues/1015
> Reported-by: Andrea Righi <andrea.righi@canonical.com>
> Tested-by: Raphael Nestler <raphael.nestler@gmail.com>
> Tested-by: Andrea Righi <andrea.righi@canonical.com>
> Cc: stable@vger.kernel.org
> Signed-off-by: Miguel Ojeda <ojeda@kernel.org>
> ---

Applied to linux-kbuild/fixes. Thanks.

I believe this is a fix, so I will include it
in my next pull request.

>  scripts/Makefile.build | 5 ++++-
>  1 file changed, 4 insertions(+), 1 deletion(-)
>
> diff --git a/scripts/Makefile.build b/scripts/Makefile.build
> index 6413342a03f4..82e3fb19fdaf 100644
> --- a/scripts/Makefile.build
> +++ b/scripts/Makefile.build
> @@ -264,6 +264,9 @@ $(obj)/%.lst: $(src)/%.c FORCE
>
>  rust_allowed_features := new_uninit
>
> +# `--out-dir` is required to avoid temporaries being created by `rustc` in the
> +# current working directory, which may be not accessible in the out-of-tree
> +# modules case.
>  rust_common_cmd = \
>         RUST_MODFILE=$(modfile) $(RUSTC_OR_CLIPPY) $(rust_flags) \
>         -Zallow-features=$(rust_allowed_features) \
> @@ -272,7 +275,7 @@ rust_common_cmd = \
>         --extern alloc --extern kernel \
>         --crate-type rlib -L $(objtree)/rust/ \
>         --crate-name $(basename $(notdir $@)) \
> -       --emit=dep-info=$(depfile)
> +       --out-dir $(dir $@) --emit=dep-info=$(depfile)
>
>  # `--emit=obj`, `--emit=asm` and `--emit=llvm-ir` imply a single codegen unit
>  # will be used. We explicitly request `-Ccodegen-units=1` in any case, and
>
> base-commit: 06c2afb862f9da8dc5efa4b6076a0e48c3fbaaa5
> --
> 2.41.0
>

-- 
Best Regards
Masahiro Yamada