diff --git a/sys/kern/kern_sleepq.c b/sys/kern/kern_sleepq.c
index dda4eed3f1c0..e4bd395826b2 100644
--- a/sys/kern/kern_sleepq.c
+++ b/sys/kern/kern_sleepq.c
@@ -1,7 +1,7 @@
-/*	$NetBSD: kern_sleepq.c,v 1.58 2020/01/12 13:08:32 ad Exp $	*/
+/*	$NetBSD: kern_sleepq.c,v 1.59 2020/01/26 19:01:56 ad Exp $	*/
 
 /*-
- * Copyright (c) 2006, 2007, 2008, 2009, 2019 The NetBSD Foundation, Inc.
+ * Copyright (c) 2006, 2007, 2008, 2009, 2019, 2020 The NetBSD Foundation, Inc.
  * All rights reserved.
  *
  * This code is derived from software contributed to The NetBSD Foundation
@@ -35,7 +35,7 @@
  */
 
 #include <sys/cdefs.h>
-__KERNEL_RCSID(0, "$NetBSD: kern_sleepq.c,v 1.58 2020/01/12 13:08:32 ad Exp $");
+__KERNEL_RCSID(0, "$NetBSD: kern_sleepq.c,v 1.59 2020/01/26 19:01:56 ad Exp $");
 
 #include <sys/param.h>
 #include <sys/kernel.h>
@@ -114,7 +114,13 @@ sleepq_remove(sleepq_t *sq, lwp_t *l)
 
 	KASSERT(lwp_locked(l, NULL));
 
-	TAILQ_REMOVE(sq, l, l_sleepchain);
+	if ((l->l_syncobj->sobj_flag & SOBJ_SLEEPQ_NULL) == 0) {
+		KASSERT(sq != NULL);
+		TAILQ_REMOVE(sq, l, l_sleepchain);
+	} else {
+		KASSERT(sq == NULL);
+	}
+
 	l->l_syncobj = &sched_syncobj;
 	l->l_wchan = NULL;
 	l->l_sleepq = NULL;
@@ -175,6 +181,12 @@ static void
 sleepq_insert(sleepq_t *sq, lwp_t *l, syncobj_t *sobj)
 {
 
+	if ((sobj->sobj_flag & SOBJ_SLEEPQ_NULL) != 0) {
+		KASSERT(sq == NULL); 
+		return;
+	}
+	KASSERT(sq != NULL);
+
 	if ((sobj->sobj_flag & SOBJ_SLEEPQ_SORTED) != 0) {
 		lwp_t *l2;
 		const int pri = lwp_eprio(l);
@@ -441,7 +453,7 @@ sleepq_reinsert(sleepq_t *sq, lwp_t *l)
 {
 
 	KASSERT(l->l_sleepq == sq);
-	if ((l->l_syncobj->sobj_flag & SOBJ_SLEEPQ_SORTED) == 0) {
+	if ((l->l_syncobj->sobj_flag & SOBJ_SLEEPQ_SORTED) == 0) { 
 		return;
 	}
 
diff --git a/sys/sys/syncobj.h b/sys/sys/syncobj.h
index df890cde94fe..458318875934 100644
--- a/sys/sys/syncobj.h
+++ b/sys/sys/syncobj.h
@@ -1,7 +1,7 @@
-/*	$NetBSD: syncobj.h,v 1.8 2009/10/21 21:12:07 rmind Exp $	*/
+/*	$NetBSD: syncobj.h,v 1.9 2020/01/26 19:01:56 ad Exp $	*/
 
 /*-
- * Copyright (c) 2007, 2008 The NetBSD Foundation, Inc.
+ * Copyright (c) 2007, 2008, 2020 The NetBSD Foundation, Inc.
  * All rights reserved.
  *
  * This code is derived from software contributed to The NetBSD Foundation
@@ -54,11 +54,13 @@ struct lwp *syncobj_noowner(wchan_t);
 #define	SOBJ_SLEEPQ_SORTED	0x01
 #define	SOBJ_SLEEPQ_FIFO	0x02
 #define	SOBJ_SLEEPQ_LIFO	0x04
+#define	SOBJ_SLEEPQ_NULL	0x08
 
 extern syncobj_t	sched_syncobj;
 extern syncobj_t	mutex_syncobj;
 extern syncobj_t	rw_syncobj;
 extern syncobj_t	sleep_syncobj;
+extern syncobj_t	lwp_park_syncobj;
 
 #endif /* defined(_KERNEL) */