witness_assert
witness_assert(&rwl->rwl_lock_obj, LA_XLOCKED);
witness_assert(&rwl->rwl_lock_obj, LA_SLOCKED);
witness_assert(&rwl->rwl_lock_obj, LA_LOCKED);
witness_assert(&rwl->rwl_lock_obj, LA_UNLOCKED);
void witness_assert(const struct lock_object *, int);