// Start signaller
	atomic.StoreInt32(&issue9400.Baton, 0)
	go func() {
		// Wait for RewindAndSetgid
		for atomic.LoadInt32(&issue9400.Baton) == 0 {
			runtime.Gosched()
		}
		// Broadcast SIGSETXID
		runtime.LockOSThread()
		C.setgid(0)
		// Indicate that signalling is done
		atomic.StoreInt32(&issue9400.Baton, 0)
	}()

	// Grow the stack and put down a test pattern
	const pattern = 0x123456789abcdef

// the ID of the M the SIGUSR1 was received on. If the caller writes
// a non-zero byte to w, WaitForSigusr1 returns immediately with -1, -1.
func WaitForSigusr1(r, w int32, ready func(mp *M)) (int64, int64) {
	lockOSThread()
	// Make sure we can receive SIGUSR1.
	unblocksig(_SIGUSR1)

	waitForSigusr1.rdpipe = r
	waitForSigusr1.wrpipe = w

	mp := getg().m
	testSigusr1 = waitForSigusr1Callback
	ready(mp)

	//
	// Debuggers rely on us running on the same thread until we get to
	// dispatch the function they asked as to.
	//
	// We're going to transfer this to the new G we just created.
	lockOSThread()

	// Create a new goroutine to execute the call on. Run this on
	// the system stack to avoid growing our stack.
	systemstack(func() {
		// TODO(mknyszek): It would be nice to wrap these arguments in an allocated

	// leave the thread locked to die without a risk of the current thread
	// left lingering with incorrect namespace.
	var innerError error
	go func() {
		defer wg.Done()
		runtime.LockOSThread()
		innerError = containedCall()
	}()
	wg.Wait()

	return innerError

	go func() {
		if locked {
			runtime.LockOSThread()
		}
		for {
			select {
			case <-c:
				cack <- true
				return
			default:
				runtime.Gosched()
			}
		}
	}()
	time.Sleep(10 * time.Millisecond)
	c <- true
	<-cack
}

func TestYieldLocked(t *testing.T) {
	const N = 10
	c := make(chan bool)
	go func() {
		runtime.LockOSThread()
		for i := 0; i < N; i++ {
			runtime.Gosched()

	}
}

func TestDebugLogWraparound(t *testing.T) {
	skipDebugLog(t)

	// Make sure we don't switch logs so it's easier to fill one up.
	runtime.LockOSThread()
	defer runtime.UnlockOSThread()

	runtime.ResetDebugLog()
	var longString = strings.Repeat("a", 128)
	var want strings.Builder
	for i, j := 0, 0; j < 2*runtime.DebugLogBytes; i, j = i+1, j+len(longString) {

func (k Key) ReadSubKeyNames() ([]string, error) {
	// RegEnumKeyEx must be called repeatedly and to completion.
	// During this time, this goroutine cannot migrate away from
	// its current thread. See #49320.
	runtime.LockOSThread()
	defer runtime.UnlockOSThread()

	names := make([]string, 0)
	// Registry key size limit is 255 bytes and described there:
	// https://learn.microsoft.com/en-us/windows/win32/sysinfo/registry-element-size-limits

				if e != 0 {
					return e
				}
				return nil
			},
		},
	}

	waiter := func(q <-chan uintptr, r chan<- uintptr, once bool) {
		for x := range q {
			runtime.LockOSThread()
			v, _, e := syscall.Syscall(syscall.SYS_PRCTL, PR_GET_KEEPCAPS, 0, 0)
			if e != 0 {
				t.Errorf("tid=%d prctl(PR_GET_KEEPCAPS) failed: %v", syscall.Gettid(), e)
			} else if x != v {

		runtime.Close(w)
	}()
	runtime.Closeonexec(r)
	runtime.Closeonexec(w)

	var want, got int64
	var wg sync.WaitGroup
	ready := make(chan *runtime.M)
	wg.Add(1)
	go func() {
		runtime.LockOSThread()
		want, got = runtime.WaitForSigusr1(r, w, func(mp *runtime.M) {
			ready <- mp
		})
		runtime.UnlockOSThread()
		wg.Done()
	}()
	waitingM := <-ready
	runtime.SendSigusr1(waitingM)

	if runtime.GOOS == "android" {
		return
	}
	// Used to panic because of the UnlockOSThread below.
	C.lockOSThreadC()
}

//export lockOSThreadCallback
func lockOSThreadCallback() {
	runtime.LockOSThread()
	runtime.UnlockOSThread()
	go C.usleep(10000)
	runtime.Gosched()
}

// issue 4054 part 2 - part 1 in test.go

var issue4054b = []int{C.A, C.B, C.C, C.D, C.E, C.F, C.G, C.H, C.II, C.J}