PLOCK_WAITRES
if (p->p_lock & PLOCK_WAITRES)
KKASSERT((p->p_lock & (PLOCK_ZOMB | PLOCK_WAITRES)) == PLOCK_ZOMB);
(o | PLOCK_WAITRES) & ~PLOCK_WAITING)) {
if ((o & (PLOCK_ZOMB | PLOCK_WAITRES)) == 0) {
} else if (o & PLOCK_WAITRES) {
n = (o - 1) & ~(PLOCK_ZOMB | PLOCK_WAITING | PLOCK_WAITRES);