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

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 for Android: free password hash cracker in your pocket

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

Message-ID: <20251002194734.7cb2be8e@pumpkin>
Date: Thu, 2 Oct 2025 19:47:34 +0100
From: David Laight <david.laight.linux@...il.com>
To: Linus Torvalds <torvalds@...ux-foundation.org>
Cc: Geert Uytterhoeven <geert@...ux-m68k.org>, 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 Sep 2025 08:53:37 -0700
Linus Torvalds <torvalds@...ux-foundation.org> wrote:

> 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;}}

Should that be 'void *c(void);' (with an extra void) to avoid failing because
of the K&R function declaration?

	David

> > >
> > > 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
>