Index: sys/kern/kern_event.c
===================================================================
--- sys/kern/kern_event.c
+++ sys/kern/kern_event.c
@@ -2414,23 +2414,16 @@
     void (*kl_assert_lock)(void *, int))
 {
 
-	if (lock == NULL)
-		knl->kl_lockarg = &knlist_lock;
-	else
-		knl->kl_lockarg = lock;
+	KASSERT(lock != NULL, ("knlist_init lock NULL"));
+	KASSERT(kl_lock != NULL, ("knlist_init lock fn NULL"));
+	KASSERT(kl_unlock != NULL, ("knlist_init unlock fn NULL"));
+	KASSERT(kl_assert_lock != NULL,
+		("knlist_init assert locked fn NULL"));
 
-	if (kl_lock == NULL)
-		knl->kl_lock = knlist_mtx_lock;
-	else
-		knl->kl_lock = kl_lock;
-	if (kl_unlock == NULL)
-		knl->kl_unlock = knlist_mtx_unlock;
-	else
-		knl->kl_unlock = kl_unlock;
-	if (kl_assert_lock == NULL)
-		knl->kl_assert_lock = knlist_mtx_assert_lock;
-	else
-		knl->kl_assert_lock = kl_assert_lock;
+	knl->kl_lockarg = lock;
+	knl->kl_lock = kl_lock;
+	knl->kl_unlock = kl_unlock;
+	knl->kl_assert_lock = kl_assert_lock;
 
 	knl->kl_autodestroy = 0;
 	SLIST_INIT(&knl->kl_list);
@@ -2439,8 +2432,11 @@
 void
 knlist_init_mtx(struct knlist *knl, struct mtx *lock)
 {
+	if (lock == NULL)
+		lock = &knlist_lock;
 
-	knlist_init(knl, lock, NULL, NULL, NULL);
+	knlist_init(knl, lock, knlist_mtx_lock, knlist_mtx_unlock,
+	     knlist_mtx_assert_lock);
 }
 
 struct knlist *