diff --git a/fs/overlayfs/util.c b/fs/overlayfs/util.c
index 5d6b60d56c27..dcccb4b4a66c 100644
--- a/fs/overlayfs/util.c
+++ b/fs/overlayfs/util.c
@@ -15,6 +15,7 @@
 #include <linux/uuid.h>
 #include <linux/namei.h>
 #include <linux/ratelimit.h>
+#include <linux/overflow.h>
 #include "overlayfs.h"
 
 /* Get write access to upper mnt - may fail if upper sb was remounted ro */
@@ -145,9 +146,9 @@ void ovl_stack_free(struct ovl_path *stack, unsigned int n)
 
 struct ovl_entry *ovl_alloc_entry(unsigned int numlower)
 {
-	size_t size = offsetof(struct ovl_entry, __lowerstack[numlower]);
-	struct ovl_entry *oe = kzalloc(size, GFP_KERNEL);
+	struct ovl_entry *oe;
 
+	oe = kzalloc(struct_size(oe, __lowerstack, numlower), GFP_KERNEL);
 	if (oe)
 		oe->__numlower = numlower;