linux-kernel - Re: [PATCH] parisc: fix module loading failure of large kernel modules (take 4)

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Date:	Thu, 01 Jan 2009 18:12:41 +1100
From:	Jeremy Fitzhardinge <jeremy@...p.org>
To:	Linus Torvalds <torvalds@...ux-foundation.org>
CC:	Helge Deller <deller@....de>,
	Rusty Russell <rusty@...tcorp.com.au>,
	linux-parisc <linux-parisc@...r.kernel.org>,
	Linux Kernel Development <linux-kernel@...r.kernel.org>,
	Kyle McMartin <kyle@...artin.ca>,
	Randolph Chung <randolph@...sq.org>,
	Andrew Morton <akpm@...ux-foundation.org>,
	Sam Ravnborg <sam@...nborg.org>,
	John David Anglin <dave@...uly1.hia.nrc.ca>
Subject: Re: [PATCH] parisc: fix module loading failure of large kernel modules
 (take 4)

Linus Torvalds wrote:
> Some gcc versions will inline weak functions if they are in scope - even 
> if there is a non-weak function somewhere else. So you MUST NOT have the 
> weak definition in the same file (or indirectly called through some inline 
> functions in a header file) as the call. Because if you do, then any user 
> with the wrong version of gcc will get the weak function semantics, even 
> if it was meant to be overridden by something else.
>   

Yes.  I think this behaviour is considered to be desperately broken by 
the gcc developers and has been fixed in all recent gccs.  There are a 
couple of broken versions, and there have been patches floating around 
to just refuse to use them; otherwise __weak is effectively unusable.  
(Ah, I see Adrian has posted it again and everyone agrees with it.)

On the other hand, I have seen a couple of instances of "inline __weak" 
which is insane, but I don't know if gcc does anything crazy with it, or 
if its common enough to bother warning about.

    J
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