On Sunday 21 June 2009, Sean MacLennan wrote:

I found the source of the badness. The backtrace is correct:

uic_init_one

So that's in arch/powerpc/sysdev/uic.c.

___alloc_bootmem
___alloc_bootmem_nopanic
alloc_arch_preferred_bootmem

In alloc_arch_preferred_bootmem we have:

	if (WARN_ON_ONCE(slab_is_available()))
		return kzalloc(size, GFP_NOWAIT);

Since the slab is available (it had better be or the call will return
NULL), we get the badness message, then a successful return from
kzalloc.

I believe the author wants something like:

	if (slab_is_available())
		return kzalloc(size, GFP_NOWAIT);
	else
		WARN_ON_ONCE(1);

Well, I myself have no idea. It could also indicate a bug in the uic code.

But let's CC some people responsible for this code. Pekka recently added 
this WARN that triggers in your case; David and Paul look to be the 
people most involved in the uic code.

Start of the thread is at http://lkml.org/lkml/2009/6/20/165.

Cheers,
FJP