Symbol: UMTX_OP_SET_CEILING
lib/libthr/thread/thr_umtx.c
178
return (_umtx_op_err(mtx, UMTX_OP_SET_CEILING, ceiling, oldceiling, 0));
sys/kern/kern_umtx.c
4912
[UMTX_OP_SET_CEILING] = __umtx_op_set_ceiling,