diff --git a/ospfd/ospf_nsm.c b/ospfd/ospf_nsm.c
index bfd565e..8a93f0e 100644
--- a/ospfd/ospf_nsm.c
+++ b/ospfd/ospf_nsm.c
@@ -440,6 +440,11 @@
   /* call it here because we cannot call it from ospf_nsm_event */
   nsm_change_state (nbr, NSM_Down);
   
+  /* killing nbr_self is invalid */
+  assert (nbr != nbr->oi->nbr_self);
+  if (nbr == nbr->oi->nbr_self)
+    return 1;
+  
   /* Reset neighbor. */
   nsm_reset_nbr (nbr);