linux-kernel - Re: [patch V2a 2/6] kbuild: Disable CC_HAS_ASM_GOTO

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Message-ID: <CAHk-=whmf8OKRBKW_xi6SLrvicif8a2e7Pn9v6Qi+ioDJxnqmg@mail.gmail.com>
Date: Mon, 29 Sep 2025 08:53:37 -0700
From: Linus Torvalds <torvalds@...ux-foundation.org>
To: Geert Uytterhoeven <geert@...ux-m68k.org>
Cc: Peter Zijlstra <peterz@...radead.org>, Thomas Gleixner <tglx@...utronix.de>, 
	Nathan Chancellor <nathan@...nel.org>, LKML <linux-kernel@...r.kernel.org>, 
	kernel test robot <lkp@...el.com>, Russell King <linux@...linux.org.uk>, 
	linux-arm-kernel@...ts.infradead.org, 
	Christophe Leroy <christophe.leroy@...roup.eu>, Darren Hart <dvhart@...radead.org>, 
	Davidlohr Bueso <dave@...olabs.net>, André Almeida <andrealmeid@...lia.com>, 
	x86@...nel.org, Alexander Viro <viro@...iv.linux.org.uk>, 
	Christian Brauner <brauner@...nel.org>, Jan Kara <jack@...e.cz>, linux-fsdevel@...r.kernel.org
Subject: Re: [patch V2a 2/6] kbuild: Disable CC_HAS_ASM_GOTO_OUTPUT on clang <
 version 17

On Mon, 29 Sept 2025 at 04:10, Geert Uytterhoeven <geert@...ux-m68k.org> wrote:
>
> >
> > Ah, d'0h indeed.
> >
> > void b(void **);void* c();int f(void){{asm goto(""::::l0);return 0;l0:return 1;}void *x __attribute__((cleanup(b))) = c();{asm goto(""::::l1);return 2;l1:return 1;}}
> >
> > Seems to still finger the issue on x86_64. That should build on !x86
> > too, right?
>
> Thanks, builds fine on arm32, arm64, riscv, m68k, powerpc, mips, s390.

Ok, I just applied that fix directly. It's clearly not a fatal bug
since it just falls back on the non-optimal code, but it's one of
those "silly and subtle code generation issues" so I'd rather have it
fixed asap in the upstream kernel.

Geert, thanks for noticing.

             Linus