diff --git a/lib/event.c b/lib/event.c
index 5031f314..766ffa15 100644
--- a/lib/event.c
+++ b/lib/event.c
@@ -182,6 +182,7 @@ ev_run_list(event_list *l)
   WALK_LIST_FIRST(n, tmp_list)
     {
       event *e = SKIP_BACK(event, n, n);
+      ASSERT_DIE(n->next->prev == n);
 
       if (legacy)
       {
diff --git a/lib/lists.c b/lib/lists.c
index dc2e4cbb..2f92defe 100644
--- a/lib/lists.c
+++ b/lib/lists.c
@@ -208,6 +208,9 @@ add_tail_list(list *to, list *l)
   EXPENSIVE_CHECK(check_list(to, NULL));
   EXPENSIVE_CHECK(check_list(l, NULL));
 
+  ASSERT_DIE(l->head->prev == &l->head_node);
+  ASSERT_DIE(l->tail->next == &l->tail_node);
+
   node *p = to->tail;
   node *q = l->head;