diff --git a/fs/btrfs/ctree.c b/fs/btrfs/ctree.c
index f948435..bfedbbe 100644
--- a/fs/btrfs/ctree.c
+++ b/fs/btrfs/ctree.c
@@ -31,8 +31,8 @@
 
 static const struct btrfs_csums {
 	u16		size;
-	const char	*name;
-	const char	*driver;
+	const char	name[10];
+	const char	driver[12];
 } btrfs_csums[] = {
 	[BTRFS_CSUM_TYPE_CRC32] = { .size = 4, .name = "crc32c" },
 	[BTRFS_CSUM_TYPE_XXHASH] = { .size = 8, .name = "xxhash64" },
@@ -63,7 +63,8 @@
 const char *btrfs_super_csum_driver(u16 csum_type)
 {
 	/* csum type is validated at mount time */
-	return btrfs_csums[csum_type].driver ?:
+	return btrfs_csums[csum_type].driver[0] ?
+		btrfs_csums[csum_type].driver :
 		btrfs_csums[csum_type].name;
 }