mm/kasan: support per-page shadow memory to reduce memory consumption

mm/slab_common.c

Index: mm/slab_common.c
diff --git a/mm/slab_common.c b/mm/slab_common.c
index 01a0fe2eb33267f8f04f7e90fd79358cd1f41d07..4545975b1929157f86e0b3225e66ec6d6095c8c8 100644
--- a/mm/slab_common.c
+++ b/mm/slab_common.c
@@ -1112,9 +1112,16 @@ void *kmalloc_order(size_t size, gfp_t flags, unsigned int order)
 
 	flags |= __GFP_COMP;
 	page = alloc_pages(flags, order);
-	ret = page ? page_address(page) : NULL;
+	if (!page)
+		return NULL;
+
+	ret = page_address(page);
+	if (kasan_kmalloc_large(ret, size, flags)) {
+		__free_pages(page, order);
+		return NULL;
+	}
+
 	kmemleak_alloc(ret, size, 1, flags);
-	kasan_kmalloc_large(ret, size, flags);
 	return ret;
 }
 EXPORT_SYMBOL(kmalloc_order);