diff --git a/fs/ext4/mmp.c b/fs/ext4/mmp.c
index ed6548d..444b701 100644
--- a/fs/ext4/mmp.c
+++ b/fs/ext4/mmp.c
@@ -41,6 +41,8 @@
 	 * is not blocked in the elevator. */
 	if (!*bh)
 		*bh = sb_getblk(sb, mmp_block);
+	if (!*bh)
+		return -ENOMEM;
 	if (*bh) {
 		get_bh(*bh);
 		lock_buffer(*bh);