diff --git a/tools/mm/page_owner_sort.c b/tools/mm/page_owner_sort.c
index e6954909401c..904d48931af8 100644
--- a/tools/mm/page_owner_sort.c
+++ b/tools/mm/page_owner_sort.c
@@ -788,8 +788,7 @@ int main(int argc, char **argv)
 	}
 
 	fin = fopen(argv[optind], "r");
-	fout = fopen(argv[optind + 1], "w");
-	if (!fin || !fout) {
+	if (!fin) {
 		usage();
 		perror("open: ");
 		exit(1);
@@ -826,6 +825,13 @@ int main(int argc, char **argv)
 			goto out_free;
 	}
 
+	fout = fopen(argv[optind + 1], "w");
+	if (!fout) {
+		usage();
+		perror("open: ");
+		exit(1);
+	}
+
 	printf("loaded %d\n", list_size);
 
 	printf("sorting ....\n");