linux-kernel - Re: [PATCH] x86: remove unneeded endless loop in BUG()

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:	Thu, 19 Feb 2009 12:48:38 -0800
From:	"H. Peter Anvin" <hpa@...or.com>
To:	Jeremy Fitzhardinge <jeremy@...p.org>
CC:	Ingo Molnar <mingo@...e.hu>, Petr Tesarik <ptesarik@...e.cz>,
	LKML <linux-kernel@...r.kernel.org>
Subject: Re: [PATCH] x86: remove unneeded endless loop in BUG()

Jeremy Fitzhardinge wrote:
> 
> There's no reason to expect an "asm volatile" to stay put; the 
> "volatile" has nothing to do with preventing code motion.  The only way 
> to make an asm stick in one place is with data dependencies, and I'm not 
> sure what the dependency for __builtin_trap might be.  I'm guessing its 
> a "memory" clobber, but that's pure guesswork.
> 

I looked through this with HJL; the bottom line is that although it 
probably would work, it's not worth it.

I submitted GCC bug 39252 to get __builtin_not_reached(); instead.

	-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/