Re: Undefined symbols in 2.6.11-rc5-mm1

[Adrian Bunk <bunk@stusta.de>]

On Fri, Mar 04, 2005 at 02:11:13PM -0500, Kai Germaschewski wrote:
> On Fri, 4 Mar 2005, Rusty Russell wrote:
> 
> > On Wed, 2005-03-02 at 15:00 +0100, Adrian Bunk wrote:
> > > Why doesn't an EXPORT_SYMBOL create a reference?
> > 
> > It does: EXPORT_SYMBOL(x) drops the address of "x", including
> > __attribute_used__, in the __ksymtab section.
> 
> Well, the problem is that this is still an internal reference in the same 
> object file. So ld looks into the lib .a archive, determines that none of 
> the symbols in that object file are needed to resolve a reference and 
> drops the entire .o file. Doing so, it drops the __ksymtab section as 
> well, which otherwise would be used by the kernel to look up that symbol. 
> 
> So it drops the reference and the referencee ;), which is normally fine -- 
> no unresolved symbols occur. Unfortunately, the kernel really needs to 
> know the contents of the __ksymtab sections to correctly export those 
> symbols, but it doesn't reference it in any explicit way.
> 
> I don't think there's an easy fix, except for not putting such objects 
> into an archive/lib, but to link them directly.

Silly question:
What's the advantage of lib-y compared to obj-y?

> --Kai

cu
Adrian

-- 

       "Is there not promise of rain?" Ling Tan asked suddenly out
        of the darkness. There had been need of rain for many days.
       "Only a promise," Lao Er said.
                                       Pearl S. Buck - Dragon Seed