diff --git a/include/linux/swap.h b/include/linux/swap.h
index b86b5c20617d93e361d462e20c0c3c87856214b6..8dc0ea7caf02baa404e8896d13351577a177547a 100644
--- a/include/linux/swap.h
+++ b/include/linux/swap.h
@@ -21,6 +21,9 @@ struct bio;
 #define SWAP_FLAG_PRIO_SHIFT	0
 #define SWAP_FLAG_DISCARD	0x10000 /* discard swap cluster after use */
 
+#define SWAP_FLAGS_VALID	(SWAP_FLAG_PRIO_MASK | SWAP_FLAG_PREFER | \
+				 SWAP_FLAG_DISCARD)
+
 static inline int current_is_kswapd(void)
 {
 	return current->flags & PF_KSWAPD;
diff --git a/mm/swapfile.c b/mm/swapfile.c
index dae42f380d6ebcde88d3aaef6aa3cb1d64e0f5a3..fafc26d1b1dc885d2541eda3bdc5705a4fe56012 100644
--- a/mm/swapfile.c
+++ b/mm/swapfile.c
@@ -2022,6 +2022,9 @@ SYSCALL_DEFINE2(swapon, const char __user *, specialfile, int, swap_flags)
 	struct page *page = NULL;
 	struct inode *inode = NULL;
 
+	if (swap_flags & ~SWAP_FLAGS_VALID)
+		return -EINVAL;
+
 	if (!capable(CAP_SYS_ADMIN))
 		return -EPERM;