diff --git a/mod/silverbox/box.c b/mod/silverbox/box.c
index 384a7cee173ac2466787c5bbfd6d85939d3e53ff..8885d573af83c0ddc0d1bfcd73a135e272115f1f 100644
--- a/mod/silverbox/box.c
+++ b/mod/silverbox/box.c
@@ -750,7 +750,7 @@ box_dispach(struct box_txn *txn, enum box_mode mode, u16 op, struct tbuf *data)
 
 	txn->op = op;
 	txn->n = read_u32(data);
-	if (txn->n > nelem(namespace) - 1)
+	if (txn->n > namespace_count - 1)
 		box_raise(ERR_CODE_NO_SUCH_NAMESPACE, "bad namespace number");
 	txn->index = &namespace[txn->n].index[0];