diff --git a/disk-utils/mkfs.cramfs.c b/disk-utils/mkfs.cramfs.c
index 94f0c3397..b5edb7a4b 100644
--- a/disk-utils/mkfs.cramfs.c
+++ b/disk-utils/mkfs.cramfs.c
@@ -218,8 +218,10 @@ identical_file(struct entry *e1, struct entry *e2){
 	if (!start1)
 		return 0;
 	start2 = do_mmap(e2->path, e2->size, e2->mode);
-	if (!start2)
+	if (!start2) {
+		do_munmap(start1, e1->size, e1->mode);
 		return 0;
+	}
 	equal = !memcmp(start1, start2, e1->size);
 	do_munmap(start1, e1->size, e1->mode);
 	do_munmap(start2, e2->size, e2->mode);