FAILED: patch "[PATCH] objtool/rust: add one more `noreturn` Rust function for Rust 1.101.0" failed to apply to 5.15-stable tree

FAILED: patch "[PATCH] objtool/rust: add one more `noreturn` Rust function for Rust 1.101.0" failed to apply to 5.15-stable tree

[Sasha Levin]

The patch below does not apply to the 5.15-stable tree.
If someone wants it applied there, or to any other stable or longterm
tree, then please email the backport, including the original git commit
id to <stable@vger.kernel.org>.

To reproduce the conflict and resubmit, you may use the following commands:

git fetch https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/ linux-5.15.y
git checkout FETCH_HEAD
git cherry-pick -x 6b704ec9007a3f23ec5ded8f320825ac444f307d
# <resolve conflicts, build, test, etc.>
git commit -s
git send-email --to '<stable@vger.kernel.org>' --in-reply-to '20261107061000-failed-5.15-6b704ec9007a@kernel.org' --subject-prefix 'PATCH 5.15.y' 'HEAD^..'

Thanks,
Sasha

------------------ original commit in Linus's tree ------------------

From 6b704ec9007a3f23ec5ded8f320825ac444f307d Mon Sep 17 00:00:00 2001
From: Miguel Ojeda <ojeda@kernel.org>
Date: Sun, 18 Oct 2026 15:13:13 +0200
Subject: [PATCH] objtool/rust: add one more `noreturn` Rust function for Rust
 1.101.0

Starting with Rust 1.101.0 (expected 2026-12-24), `objtool` may report:

    rust/kernel.o: warning: objtool: _R..._4core6result13unwrap_failed...()
    falls through to next function _R..._4core6result13unwrap_failed...()

(and others) due to calls to the `noreturn` symbol:

    core::result::unwrap_failed::unwrap_failed_inner

Rust introduced this helper when making `unwrap_failed` generic [1]. The
existing entry for `unwrap_failed` does not match the new helper.

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@vger.kernel.org # Needed in 6.12.y and later (Rust is pinned in older LTSs).
Cc: Josh Poimboeuf <jpoimboe@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Link: https://github.com/rust-lang/rust/pull/164059 [1]
Assisted-by: LLM
Link: https://patch.msgid.link/20261018131313.59391-1-ojeda@kernel.org
Signed-off-by: Miguel Ojeda <ojeda@kernel.org>
---
 tools/objtool/check.c | 1 +
 1 file changed, 1 insertion(+)

diff --git a/tools/objtool/check.c b/tools/objtool/check.c
index 464f6c9d9ff0b..931c5c412f15d 100644
--- a/tools/objtool/check.c
+++ b/tools/objtool/check.c
@@ -201,6 +201,7 @@ static bool is_rust_noreturn(const struct symbol *func)
 	       str_ends_with(func->name, "_4core6option13expect_failed")				||
 	       str_ends_with(func->name, "_4core6option13unwrap_failed")				||
 	       str_ends_with(func->name, "_4core6result13unwrap_failed")				||
+	       str_ends_with(func->name, "_4core6result13unwrap_failed19unwrap_failed_inner")		||
 	       str_ends_with(func->name, "_4core9panicking5panic")					||
 	       str_ends_with(func->name, "_4core9panicking9panic_fmt")					||
 	       str_ends_with(func->name, "_4core9panicking14panic_explicit")				||
-- 
2.53.0

Re: FAILED: patch "[PATCH] objtool/rust: add one more `noreturn` Rust function for Rust 1.101.0" failed to apply to 5.15-stable tree

[Miguel Ojeda]

On Sat, Nov 7, 2026 at 12:10 PM Sasha Levin <sashal@kernel.org> wrote:
>
> Cc: stable@vger.kernel.org # Needed in 6.12.y and later (Rust is pinned in older LTSs).

5.15 has no Rust, so please skip it.

Cheers,
Miguel

Re: FAILED: patch "[PATCH] objtool/rust: add one more `noreturn` Rust function for Rust 1.101.0" failed to apply to 5.15-stable tree

[Sasha Levin]

On Sat, Nov 07, 2026 at 01:28:36PM +0100, Miguel Ojeda wrote:
>On Sat, Nov 7, 2026 at 12:10 PM Sasha Levin <sashal@kernel.org> wrote:
>>
>> Cc: stable@vger.kernel.org # Needed in 6.12.y and later (Rust is pinned in older LTSs).
>
>5.15 has no Rust, so please skip it.

Ah, we don't parse free form text too well over there. I'd suggest just
sticking to the format we define in
Documentation/process/stable-kernel-rules.rst:

	Cc: <stable@vger.kernel.org> # 6.12.x

-- 
Thanks,
Sasha