uc.uc_link = nil
	uc.uc_sigmask = sigset_all

	var oset sigset
	sigprocmask(_SIG_SETMASK, &sigset_all, &oset)

	lwp_mcontext_init(&uc.uc_mcontext, stk, mp, mp.g0, abi.FuncPCABI0(netbsdMstart))

	ret := retryOnEAGAIN(func() int32 {
		errno := lwp_create(unsafe.Pointer(&uc), _LWP_DETACHED, unsafe.Pointer(&mp.procid))
		// lwp_create returns negative errno
		return -errno
	})
	sigprocmask(_SIG_SETMASK, &oset, nil)

		exit(1)
	}

	// Finally, create the thread. It starts at mstart_stub, which does some low-level
	// setup and then calls mstart.
	var oset sigset
	sigprocmask(_SIG_SETMASK, &sigset_all, &oset)
	err = retryOnEAGAIN(func() int32 {
		return pthread_create(&attr, abi.FuncPCABI0(mstart_stub), unsafe.Pointer(mp))
	})
	sigprocmask(_SIG_SETMASK, &oset, nil)
	if err != 0 {
		writeErrStr(failthreadcreate)
		exit(1)
	}
}

		parent_tid: nil,
		tls_base:   unsafe.Pointer(&mp.tls[0]),
		tls_size:   unsafe.Sizeof(mp.tls),
	}

	var oset sigset
	sigprocmask(_SIG_SETMASK, &sigset_all, &oset)
	ret := retryOnEAGAIN(func() int32 {
		errno := thr_new(&param, int32(unsafe.Sizeof(param)))
		// thr_new returns negative errno
		return -errno
	})
	sigprocmask(_SIG_SETMASK, &oset, nil)
	if ret != 0 {

	}

	// Disable signals during create, so that the new thread starts
	// with signals disabled. It will enable them in minit.
	sigprocmask(_SIG_SETMASK, &sigset_all, &oset)
	ret = retryOnEAGAIN(func() int32 {
		return pthread_create(&tid, &attr, abi.FuncPCABI0(tstart_sysvicall), unsafe.Pointer(mp))
	})
	sigprocmask(_SIG_SETMASK, &oset, nil)
	if ret != 0 {

	}

	// Disable signals during clone, so that the new thread starts
	// with signals disabled. It will enable them in minit.
	var oset sigset
	sigprocmask(_SIG_SETMASK, &sigset_all, &oset)
	ret := retryOnEAGAIN(func() int32 {
		r := clone(cloneFlags, stk, unsafe.Pointer(mp), unsafe.Pointer(mp.g0), unsafe.Pointer(abi.FuncPCABI0(mstart)))
		// clone returns positive TID, negative errno.
		// We don't care about the TID.