SLUB: allocate smallest object size if the user asks for 0 bytes

Makes SLUB behave like SLAB in this area to avoid issues....

Throw a stack dump to alert people.

At some point the behavior should be switched back.  NULL is no memory as
far as I can tell and if the use asked for 0 bytes then he need to get no
memory.

Signed-off-by: Christoph Lameter <clameter@sgi.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
diff --git a/mm/slub.c b/mm/slub.c
index 4a8585b..9d52cce 100644
--- a/mm/slub.c
+++ b/mm/slub.c
@@ -1979,7 +1979,7 @@
 {
 	int index = kmalloc_index(size);
 
-	if (!size)
+	if (!index)
 		return NULL;
 
 	/* Allocation too large? */