KN_DETACHED
knchild->kn_status = KN_DETACHED;
if ((kn->kn_status & KN_DETACHED) == 0) {
kn->kn_status |= KN_DETACHED;
if ((kn->kn_status & KN_DETACHED) == 0) {
kn->kn_status |= KN_DETACHED;