UMTX_OP_MUTEX_WAKE2
UMTX_OP_MUTEX_WAKE2, mp->m_lock.m_flags,
(void)_umtx_op_err(mtx, UMTX_OP_MUTEX_WAKE2,
[UMTX_OP_MUTEX_WAKE2] = __umtx_op_wake2_umutex,