Index: kernel/generic/src/adt/btree.c
===================================================================
--- kernel/generic/src/adt/btree.c	(revision 52c79ac323b577fe6bcbf65a35e13e5e0d2043cb)
+++ kernel/generic/src/adt/btree.c	(revision 7bcfbbc039dd4d392dc880cbc1a87b94b7ca853f)
@@ -971,5 +971,5 @@
 		printf("(");
 		for (i = 0; i < node->keys; i++) {
-			printf("%lld%s", node->key[i], i < node->keys - 1 ? "," : "");
+			printf("%llu%s", node->key[i], i < node->keys - 1 ? "," : "");
 			if (node->depth && node->subtree[i]) {
 				list_append(&node->subtree[i]->bfs_link, &head);
@@ -993,5 +993,5 @@
 		printf("(");
 		for (i = 0; i < node->keys; i++)
-			printf("%lld%s", node->key[i], i < node->keys - 1 ? "," : "");
+			printf("%llu%s", node->key[i], i < node->keys - 1 ? "," : "");
 		printf(")");
 	}