taskq_del_barrier(9) and timeout_del_barrier(9) should always call taskq_barrier(9) and timeout_barrier(9) respectively.

In the case that task or timeout were scheduled to run both
*_del_barrier(9) only remove it from pending queue and doesn't wait its
finish. However task could be simultaneously running and scheduled to the
next run, so they need to always wait until running handler has completed.

ok dlg

sys/kern/kern_task.c

···
-/*	$OpenBSD: kern_task.c,v 1.35 2024/05/14 08:26:13 jsg Exp $ */
+/*	$OpenBSD: kern_task.c,v 1.36 2025/01/13 03:21:10 mvs Exp $ */
 
 /*
  * Copyright (c) 2013 David Gwynne <[e-mail]>
···
 {
 	WITNESS_CHECKORDER(&tq->tq_lock_object, LOP_NEWORDER, NULL);
 
-	if (task_del(tq, t))
-		return;
-
+	task_del(tq, t);
 	taskq_do_barrier(tq);
 }
 

sys/kern/kern_timeout.c

···
-/*	$OpenBSD: kern_timeout.c,v 1.100 2024/11/07 16:02:29 miod Exp $	*/
+/*	$OpenBSD: kern_timeout.c,v 1.101 2025/01/13 03:21:10 mvs Exp $	*/
 /*
  * Copyright (c) 2001 Thomas Nordin <[e-mail]>
  * Copyright (c) 2000-2001 Artur Grabowski <[e-mail]>
···
 	timeout_sync_order(ISSET(to->to_flags, TIMEOUT_PROC));
 
 	removed = timeout_del(to);
-	if (!removed)
-		timeout_barrier(to);
+	timeout_barrier(to);
 
 	return removed;
 }