diff --git a/fs/overlayfs/readdir.c b/fs/overlayfs/readdir.c
index 881ec5592da5..efe4700c797e 100644
--- a/fs/overlayfs/readdir.c
+++ b/fs/overlayfs/readdir.c
@@ -13,6 +13,7 @@
 #include <linux/security.h>
 #include <linux/cred.h>
 #include <linux/ratelimit.h>
+#include <linux/overflow.h>
 #include "overlayfs.h"
 
 struct ovl_cache_entry {
@@ -147,9 +148,8 @@ static struct ovl_cache_entry *ovl_cache_entry_new(struct ovl_readdir_data *rdd,
 						   u64 ino, unsigned int d_type)
 {
 	struct ovl_cache_entry *p;
-	size_t size = offsetof(struct ovl_cache_entry, name[len + 1]);
 
-	p = kmalloc(size, GFP_KERNEL);
+	p = kmalloc(struct_size(p, name, len + 1), GFP_KERNEL);
 	if (!p)
 		return NULL;