linux-kernel - Re: [BUG FIX] Make x86_32 uni-processor Atomic ops, Atomic

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]

Date:	Fri, 22 May 2009 14:20:06 -0500
From:	"Michael S. Zick" <lkml@...ethan.org>
To:	"H. Peter Anvin" <hpa@...or.com>
Cc:	Ingo Molnar <mingo@...e.hu>, Thomas Gleixner <tglx@...utronix.de>,
	linux-kernel@...r.kernel.org
Subject: Re: [BUG FIX] Make x86_32 uni-processor Atomic ops, Atomic

On Fri May 22 2009, H. Peter Anvin wrote:
> Ingo Molnar wrote:
> > * Michael S. Zick <lkml@...ethan.org> wrote:
> > 
> >> Found in the bit-rot for 32-bit, x86, Uni-processor builds:
> >>
> >> diff --git a/arch/x86/include/asm/alternative.h b/arch/x86/include/asm/alternative.h
> >> index f6aa18e..3c790ef 100644
> >> --- a/arch/x86/include/asm/alternative.h
> >> +++ b/arch/x86/include/asm/alternative.h
> >> @@ -35,7 +35,7 @@
> >>                 "661:\n\tlock; "
> >>
> >>  #else /* ! CONFIG_SMP */
> >> -#define LOCK_PREFIX ""
> >> +#define LOCK_PREFIX "\n\tlock; "
> >>  #endif
> > 
> > What is your motivation for this change? At first sight this makes 
> > the UP kernel a bit larger and a bit smaller. Are you fixing some 
> > real regression/bug here?
> > 
> 
> That looks very odd indeed.  The whole point of the LOCK_PREFIX macro is
> to squelch it on UP (locks that should not be squelched on UP should not
> be annotated LOCK_PREFIX.)
> 

OK, will inspect for that possibility.
We may just have a mis-use of LOCK_PREFIX.

Mike
> 	-hpa
> 
> --
> To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
> the body of a message to majordomo@...r.kernel.org
> More majordomo info at  http://vger.kernel.org/majordomo-info.html
> Please read the FAQ at  http://www.tux.org/lkml/
> 
> 


--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@...r.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/