func StackMemory() {
	mem1, err := getPagefileUsage()
	if err != nil {
		panic(err)
	}
	const threadCount = 100
	var wg sync.WaitGroup
	for i := 0; i < threadCount; i++ {
		wg.Add(1)
		go func() {
			runtime.LockOSThread()
			wg.Done()
			select {}
		}()
	}
	wg.Wait()
	mem2, err := getPagefileUsage()
	if err != nil {
		panic(err)
	}
	// assumes that this process creates 1 thread for each

	defer func() {
		c <- 0
	}()
	go func() {
		os.Exit(<-c)
	}()
	runtime.Goexit()
}

func main() {
}

/* Before fix:

invalid m->locked = 2
fatal error: internal lockOSThread error

goroutine 2 [runnable]:
runtime.MHeap_Scavenger()
	/Users/rsc/g/go/src/pkg/runtime/mheap.c:438
runtime.goexit()
	/Users/rsc/g/go/src/pkg/runtime/proc.c:1313
created by runtime.main

		if err != nil {
			t.Fatal(err)
		}
		runtime.GOMAXPROCS(ogomaxprocs)
		debug.SetGCPercent(ogcpercent)
	}
}

func debugCallWorker(ready chan<- *runtime.G, stop *uint32, done chan<- error) {
	runtime.LockOSThread()
	defer runtime.UnlockOSThread()

	ready <- runtime.Getg()

	x := 2
	debugCallWorker2(stop, &x)
	if x != 1 {
		done <- fmt.Errorf("want x = 2, got %d; register pointer not adjusted?", x)
	}

// The idea is to get some threads going, so that a signal will be delivered
// to a thread started by Go.
//
//export RunGoroutines
func RunGoroutines() {
	for i := 0; i < 4; i++ {
		go func() {
			runtime.LockOSThread()
			select {}
		}()
	}
}

// Block blocks the current thread while running Go code.
//
//export Block
func Block() {
	select {}
}

var P *byte

// pointer errors.
type coro struct {
	gp guintptr
	f  func(*coro)

	// State for validating thread-lock interactions.
	mp        *m
	lockedExt uint32 // mp's external LockOSThread counter at coro creation time.
	lockedInt uint32 // mp's internal lockOSThread counter at coro creation time.
}

//go:linkname newcoro

// newcoro creates a new coro containing a
// goroutine blocked waiting to run f
// and returns that coro.

	// 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

		// Lock the current goroutine to its process
		// and store the pid in io so that Cancel can
		// interrupt it. We ignore the "hangup" signal,
		// so the signal does not take down the entire
		// Go runtime.
		runtime.LockOSThread()
		runtime_ignoreHangup()
		aio.pid = syscall.Getpid()
		aio.mu.Unlock()

		n, err := fn(b)

		aio.mu.Lock()
		aio.pid = -1
		runtime_unignoreHangup()
		aio.mu.Unlock()

	// 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