Index: linux-2.6.21-rc1/mm/slub.c
===================================================================
--- linux-2.6.21-rc1.orig/mm/slub.c	2007-02-26 05:43:17.000000000 -0800
+++ linux-2.6.21-rc1/mm/slub.c	2007-02-26 15:34:06.000000000 -0800
@@ -1318,6 +1318,10 @@
 	BUG_ON(!page);
 	s = page->slab;
 	BUG_ON(!s);
+	if (s->flags & SLAB_RED_ZONE)
+		return s->objsize;
+	if (s->flags & (SLAB_DESTROY_BY_RCU | SLAB_STORE_USER))
+		return s->inuse;
 	return s->size;
 }
 EXPORT_SYMBOL(ksize);