MUTEX_OWNER
#define MUTEX_OWNER(mp) ((ulwp_t *)(uintptr_t)(mp)->mutex_owner)
#define MUTEX_OWNER(lp) ((kthread_id_t)((lp)->m_owner & MUTEX_THREAD))
#define MUTEX_OWNER(lp) ((kthread_id_t)((lp)->m_owner << PTR24_LSB))
#define MUTEX_OWNER(lp) ((kthread_id_t)((lp)->m_owner & MUTEX_THREAD))