linux-kernel - Re: [PATCH 1/2] objtool/rust: add one more `noreturn` Rust function for Rust 1.89.0

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-ID: <CAH5fLgjtU1u=h8FY3im364AsC21GitnrjhBT=YJMmipH_ZWnQA@mail.gmail.com>
Date: Mon, 14 Jul 2025 10:48:33 +0200
From: Alice Ryhl <aliceryhl@...gle.com>
To: Peter Zijlstra <peterz@...radead.org>
Cc: Miguel Ojeda <ojeda@...nel.org>, Alex Gaynor <alex.gaynor@...il.com>, 
	Masahiro Yamada <masahiroy@...nel.org>, Josh Poimboeuf <jpoimboe@...nel.org>, 
	Boqun Feng <boqun.feng@...il.com>, Gary Guo <gary@...yguo.net>, 
	Björn Roy Baron <bjorn3_gh@...tonmail.com>, 
	Benno Lossin <lossin@...nel.org>, Andreas Hindborg <a.hindborg@...nel.org>, 
	Trevor Gross <tmgross@...ch.edu>, Danilo Krummrich <dakr@...nel.org>, rust-for-linux@...r.kernel.org, 
	Nathan Chancellor <nathan@...nel.org>, Nicolas Schier <nicolas@...sle.eu>, linux-kbuild@...r.kernel.org, 
	linux-kernel@...r.kernel.org, patches@...ts.linux.dev, stable@...r.kernel.org
Subject: Re: [PATCH 1/2] objtool/rust: add one more `noreturn` Rust function
 for Rust 1.89.0

On Mon, Jul 14, 2025 at 10:46 AM Peter Zijlstra <peterz@...radead.org> wrote:
>
> On Sat, Jul 12, 2025 at 06:01:02PM +0200, Miguel Ojeda wrote:
> > Starting with Rust 1.89.0 (expected 2025-08-07), under
> > `CONFIG_RUST_DEBUG_ASSERTIONS=y`, `objtool` may report:
> >
> >     rust/kernel.o: warning: objtool: _R..._6kernel4pageNtB5_4Page8read_raw()
> >     falls through to next function _R..._6kernel4pageNtB5_4Page9write_raw()
> >
> > (and many others) due to calls to the `noreturn` symbol:
> >
> >     core::panicking::panic_nounwind_fmt
> >
> > Thus add the mangled one to the list so that `objtool` knows it is
> > actually `noreturn`.
> >
> > See commit 56d680dd23c3 ("objtool/rust: list `noreturn` Rust functions")
> > for more details.
> >
> > Cc: stable@...r.kernel.org # Needed in 6.12.y and later (Rust is pinned in older LTSs).
> > Cc: Josh Poimboeuf <jpoimboe@...nel.org>
> > Cc: Peter Zijlstra <peterz@...radead.org>
> > Signed-off-by: Miguel Ojeda <ojeda@...nel.org>
>
> Acked-by: Peter Zijlstra (Intel) <peterz@...radead.org>
>
> > ---
> >  tools/objtool/check.c | 1 +
> >  1 file changed, 1 insertion(+)
> >
> > diff --git a/tools/objtool/check.c b/tools/objtool/check.c
> > index f23bdda737aa..3257eefc41ed 100644
> > --- a/tools/objtool/check.c
> > +++ b/tools/objtool/check.c
> > @@ -224,6 +224,7 @@ static bool is_rust_noreturn(const struct symbol *func)
> >              str_ends_with(func->name, "_4core9panicking14panic_explicit")                            ||
> >              str_ends_with(func->name, "_4core9panicking14panic_nounwind")                            ||
> >              str_ends_with(func->name, "_4core9panicking18panic_bounds_check")                        ||
> > +            str_ends_with(func->name, "_4core9panicking18panic_nounwind_fmt")                        ||
> >              str_ends_with(func->name, "_4core9panicking19assert_failed_inner")                       ||
> >              str_ends_with(func->name, "_4core9panicking30panic_null_pointer_dereference")            ||
> >              str_ends_with(func->name, "_4core9panicking36panic_misaligned_pointer_dereference")      ||
>
> Just having "_4core9panicking" substring is not sufficient?

That prefix just means it is defined in the panicking.rs file, which
also has a few functions that are not noreturn.

Alice