diff --git a/ospf6d/ospf6d.c b/ospf6d/ospf6d.c
index eae01af..387f692 100644
--- a/ospf6d/ospf6d.c
+++ b/ospf6d/ospf6d.c
@@ -1854,6 +1854,8 @@
 void
 ospf6_clean (void)
 {
+  if (!ospf6)
+    return;
   if (ospf6->route_table)
     ospf6_route_remove_all (ospf6->route_table);
   if (ospf6->brouter_table)