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From: Jeremy Fitzhardinge <jeremy@goop.org>
To: Al Viro <viro@ftp.linux.org.uk>
Cc: Linus Torvalds <torvalds@linux-foundation.org>,
	linux-kernel@vger.kernel.org, linux-arch@vger.kernel.org
Subject: Re: [PATCH][RFC] getting rid of stupid loop in BUG()
Date: Tue, 24 Jul 2007 14:14:57 -0700	[thread overview]
Message-ID: <46A66BD1.9020802@goop.org> (raw)
In-Reply-To: <20070724200401.GU21668@ftp.linux.org.uk>

Al Viro wrote:
> On Tue, Jul 24, 2007 at 12:13:19PM -0700, Jeremy Fitzhardinge wrote:
>   
>> Al Viro wrote:
>>     
>>> Works here...
>>>   
>>>       
>> Hm, doesn't here:
>>
>>   CC      arch/i386/kernel/irq.o
>> /home/jeremy/hg/xen/paravirt/linux/arch/i386/kernel/irq.c: In function '__BUG':
>> include2/asm/bug.h:29: warning: 'noreturn' function does return
>>
>> This is with current FC7 distro gcc: gcc version 4.1.2 20070502 (Red Hat
>> 4.1.2-12)
>>     
>
> Interesting...  Looks like it's both version- and flags-dependent.
> Oh, well...
>
> BTW, alpha, frv, m68k and s390 have BUG() that is not recognized as
> noreturn by gcc.
>   

Yes, it was something I added because I thought it would be useful. 
Traditionally, BUG has not affected gcc's control flow analysis.

The other option is trying to use __builtin_trap, which happens to
generate ud2a on i386.  But I don't think its necessarily guaranteed to
always do that, and I don't know if it does anything useful for other
architectures.

    J

  reply	other threads:[~2007-07-24 21:16 UTC|newest]

Thread overview: 36+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2007-07-24 15:39 [PATCH][RFC] getting rid of stupid loop in BUG() Al Viro
2007-07-24 16:56 ` Jeremy Fitzhardinge
2007-07-24 17:03   ` H. Peter Anvin
2007-07-24 17:14   ` Al Viro
2007-07-24 17:28     ` H. Peter Anvin
2007-07-24 18:58       ` Jeremy Fitzhardinge
2007-07-24 19:01         ` H. Peter Anvin
2007-07-24 19:13     ` Jeremy Fitzhardinge
2007-07-24 20:04       ` Al Viro
2007-07-24 21:14         ` Jeremy Fitzhardinge [this message]
2007-07-25  2:31 ` Trent Piepho
2007-07-25  2:50   ` Keith Owens
2007-07-25  5:09     ` H. Peter Anvin
2007-07-25  6:24       ` Jeremy Fitzhardinge
2007-07-25  6:29         ` David Miller
2007-07-25  6:50           ` Heiko Carstens
2007-07-25 16:56           ` Linus Torvalds
2007-07-25 17:00             ` Jeremy Fitzhardinge
2007-07-25 17:03               ` H. Peter Anvin
2007-07-25 17:19               ` Linus Torvalds
2007-07-25 17:25                 ` Al Viro
2007-07-25 17:36                   ` Jeremy Fitzhardinge
2007-07-25 19:35                     ` David Miller
2007-07-25 20:26                       ` H. Peter Anvin
2007-07-25 19:28               ` David Miller
2007-07-25 17:19             ` Al Viro
2007-07-25 17:22               ` H. Peter Anvin
2007-07-25 17:26                 ` Al Viro
2007-07-25 17:35                   ` David Howells
2007-07-25 17:41               ` Jeremy Fitzhardinge
2007-07-25 20:29                 ` Chuck Ebbert
2007-07-25 20:37                   ` H. Peter Anvin
2007-07-25 22:01                     ` David Miller
2007-07-25 18:24               ` Linus Torvalds
2007-07-25 17:36             ` Al Viro
2007-07-25 17:44               ` Jeremy Fitzhardinge

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