Re: 2.6.21-rc7-mm1 on test.kernel.org

[Andrew Morton <akpm@linux-foundation.org>]

On Tue, 24 Apr 2007 17:51:27 -0700 Badari Pulavarty <pbadari@gmail.com> wrote:

> On Tue, 2007-04-24 at 15:51 -0700, Andrew Morton wrote:
> > Andy, I'm looking at the power4 build:
> > 
> > http://test.kernel.org/abat/84751/debug/test.log.0
> > 
> > which has
> > 
> >   LD      init/built-in.o
> >   LD      .tmp_vmlinux1
> > init/built-in.o(.init.text+0x32e4): In function `.rd_load_image':
> > : undefined reference to `.__kmalloc_size_too_large'
> > fs/built-in.o(.text+0xa60f0): In function `.ext3_fill_super':
> > : undefined reference to `.__kmalloc_size_too_large'
> > fs/built-in.o(.text+0xbe934): In function `.ext2_fill_super':
> > : undefined reference to `.__kmalloc_size_too_large'
> > fs/built-in.o(.text+0xf3370): In function `.nfs4_proc_lookup':
> > 
> > something has gone stupid with kmalloc there, and I cannot reproduce it
> > with my compiler and with your (very old) .config at
> > http://ftp.kernel.org/pub/linux/kernel/people/mbligh/config/abat/power4
> > 
> > So I'm a bit stumped.  Does autotest just do `yes "" | make oldconfig' or
> > what?  When I do that, I get SLUB, but no compile errors.
> > 
> > And do you know what compiler version is being used there?
> 
> include/linux/slub_def.h:
> 
> static inline struct kmem_cache *kmalloc_slab(size_t size)
> {
>         int index = kmalloc_index(size);
> 
>         if (index == 0)
>                 return NULL;
> 
>         if (index < 0) {
>                 /*
>                  * Generate a link failure. Would be great if we could
>                  * do something to stop the compile here.
>                  */
>                 extern void __kmalloc_size_too_large(void);
>                 __kmalloc_size_too_large();
>         }
>         return &kmalloc_caches[index];
> }
> 
> hmm.. 
> 
> gcc version 3.3.3 -- generates those link failures
> gcc version 4.1.0 -- doesn't generate this error

My power box is 3.4.4 and it doesn't do that either.  I guess it's just a
gcc buglet.

Poor Christoph ;)

I wonder why slab doesn't hit that problem.

I wonder whether slub should use kmalloc-sizes.h.

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