htb_safe_rb_erase
htb_safe_rb_erase(&parent->pq_node,
htb_safe_rb_erase(&cl->pq_node,
htb_safe_rb_erase(&parent->pq_node, &q->hlevel[0].wait_pq);
htb_safe_rb_erase(cl->node + prio, &hprio->row);
htb_safe_rb_erase(cl->node + prio,
htb_safe_rb_erase(&cl->pq_node, &q->hlevel[cl->level].wait_pq);
htb_safe_rb_erase(p, wait_pq);