linux-kernel - Re: [PATCH][RFC] getting rid of stupid loop in BUG()

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Date:	Tue, 24 Jul 2007 10:03:43 -0700
From:	"H. Peter Anvin" <hpa@...or.com>
To:	Jeremy Fitzhardinge <jeremy@...p.org>
CC:	Al Viro <viro@....linux.org.uk>,
	Linus Torvalds <torvalds@...ux-foundation.org>,
	linux-kernel@...r.kernel.org, linux-arch@...r.kernel.org
Subject: Re: [PATCH][RFC] getting rid of stupid loop in BUG()

Jeremy Fitzhardinge wrote:
> Al Viro wrote:
>> 	AFAICS, the patch below should do it for i386; instead of
>> using a dummy loop to tell gcc that this sucker never returns,
>> we do
>> static void __always_inline __noreturn __BUG(const char *file, int line);
>> containing the actual asm we want to insert and define BUG() as
>> __BUG(__FILE__, __LINE__).  It looks safe, but I don't claim enough
>> experience with gcc __asm__ potential nastiness, so...
>>
>> Comments, objections?
>>   
> 
> Does it work?  When I wrote the BUG code I tried this, but gcc kept
> warning about "noreturn function returns".  I couldn't work out a way to
> convince gcc that the asm is the end of the line.
> 
> I'm actually in favour of dropping the loop and the noreturn stuff
> altogether.  It means that gcc thinks everything is live at the time of
> the BUG, and the debugging info at the point of the ud2a is more useful.

How much code would that add to the kernel?

	-hpa
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