diff --git a/lib/util/idtree.c b/lib/util/idtree.c
index 2104c741f3e..e2cfcc50315 100644
--- a/lib/util/idtree.c
+++ b/lib/util/idtree.c
@@ -181,8 +181,13 @@ restart:
 	 */
 	n = id;
 	while (p->bitmap == IDR_FULL) {
-		if (!(p = pa[++l]))
+		if (l >= MAX_LEVEL) {
 			break;
+		}
+		p = pa[++l];
+		if (p == NULL) {
+			break;
+		}
 		n = n >> IDR_BITS;
 		set_bit((n & IDR_MASK), p->bitmap);
 	}