[BUG] 2.6.25-rc3-mm1 kernel panic while bootup on powerpc ()

[Christoph Lameter]

On Tue, 4 Mar 2008, Pekka Enberg wrote:

> >  > I suspect the WARN_ON() is bogus although I really don't know that part
> >  > of the code all too well. Mel?
> >  >
> >
> >  The warn-on is valid. A situation should not exist that allows both flags to
> >  be set. I suspect  if remove-set_migrateflags.patch was reverted from -mm
> >  the warning would not trigger. Christoph, would it be reasonable to always
> >  clear __GFP_MOVABLE when __GFP_RECLAIMABLE is set for SLAB_RECLAIM_ACCOUNT.

Slab allocations should never be passed these flags since the slabs do 
their own thing there.

The following patch would clear these in slub:

---
 mm/slub.c |    2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

Index: linux-2.6.25-rc3-mm1/mm/slub.c
===================================================================
--- linux-2.6.25-rc3-mm1.orig/mm/slub.c	2008-03-04 11:53:47.600342756 -0800
+++ linux-2.6.25-rc3-mm1/mm/slub.c	2008-03-04 11:55:40.153855150 -0800
@@ -1033,8 +1033,8 @@ static struct page *allocate_slab(struct
 	struct page *page;
 	int pages = 1 << s->order;
 
+	flags &= ~GFP_MOVABLE_MASK;
 	flags |= s->allocflags;
-
 	page = alloc_slab_page(flags | __GFP_NOWARN | __GFP_NORETRY,
 								node, s->order);
 	if (unlikely(!page)) {