slub: fix a possible memory leak

Memory allocated by kstrdup should be freed,
when kmalloc(kmem_size, GFP_KERNEL) is failed.
Acked-by: NChristoph Lameter <cl@linux.com>
Acked-by: NDavid Rientjes <rientjes@google.com>
Signed-off-by: NJoonsoo Kim <js1304@gmail.com>
Signed-off-by: NPekka Enberg <penberg@kernel.org>

mm/slub.c

@@ -3968,9 +3968,9 @@ struct kmem_cache *kmem_cache_create(const char *name, size_t size,
 			}
 			return s;
 		}
-		kfree(n);
 		kfree(s);
 	}
+	kfree(n);
 err:
 	up_write(&slub_lock);