growStack(nil)
		growDuration = time.Since(start)
	}()
	wg.Wait()
	t.Log("first growStack took", growDuration)

	// in locked goroutine
	wg.Add(1)
	go func() {
		defer wg.Done()
		LockOSThread()
		growStack(nil)
		UnlockOSThread()
	}()
	wg.Wait()

	// in finalizer
	var finalizerStart time.Time
	var started atomic.Bool
	var progress atomic.Uint32
	wg.Add(1)

			if i%2 == 1 {
				// On Plan 9, after calling LockOSThread, the goroutines
				// run on different processes which don't share the working
				// directory. This used to be an issue because Go expects
				// the working directory to be program-wide.
				// See issue 9428.
				runtime.LockOSThread()
			}
			select {
			case <-done:
				return
			case <-hold:
			}

	disableSigChan = make(chan uint32)
	enableSigChan = make(chan uint32)
	go func() {
		// Signal masks are per-thread, so make sure this goroutine stays on one
		// thread.
		LockOSThread()
		defer UnlockOSThread()
		// The sigBlocked mask contains the signals not active for os/signal,
		// initially all signals except the essential. When signal.Notify()/Stop is called,

			},
		)
	} else {
		t.Log(`skipping "use_mklink_cmd" test, mklink does not supports directory symbolic links`)
	}

	// The rest of these test requires SeCreateSymbolicLinkPrivilege to be held.
	runtime.LockOSThread()
	defer runtime.UnlockOSThread()

	err := windows.ImpersonateSelf(windows.SecurityImpersonation)
	if err != nil {
		t.Fatal(err)
	}
	defer windows.RevertToSelf()

	// will become invalid after a thread switch. This test
	// checks that the bad caching doesn't happen.

	ch := make(chan int)
	go func(ch chan int) {
		ch <- 5
		LockOSThread()
	}(ch)

	g1 := getg()

	// Block on a receive. This is likely to get us a thread
	// switch. If we yield to the sender goroutine, it will
	// lock the thread, forcing us to resume on a different

// type [*ExitError]. Other error types may be returned for other situations.
//
// If the calling goroutine has locked the operating system thread
// with [runtime.LockOSThread] and modified any inheritable OS-level
// thread state (for example, Linux or Plan 9 name spaces), the new
// process will inherit the caller's thread state.
func (c *Cmd) Run() error {
	if err := c.Start(); err != nil {

	for i := 0; i < 100000; i++ {
		testCallbackPanic(t)
	}
}

func testCallbackPanicLocked(t *testing.T) {
	runtime.LockOSThread()
	defer runtime.UnlockOSThread()

	if !lockedOSThread() {
		t.Fatal("runtime.LockOSThread didn't")
	}
	defer func() {
		s := recover()
		if s == nil {
			t.Fatal("did not panic")
		}
		if s.(string) != "callback panic" {

// the index of the last subkey (obtainable from RegQueryInfoKey),
// decrementing until index 0 is enumerated.
//
// Successive calls to this API must happen on the same OS thread,
// so call [runtime.LockOSThread] before calling this function.
func RegEnumKeyEx(key Handle, index uint32, name *uint16, nameLen *uint32, reserved *uint32, class *uint16, classLen *uint32, lastWriteTime *Filetime) (regerrno error) {

		{"GOMAXPROCS", Func, 0},
		{"GOOS", Const, 0},
		{"GOROOT", Func, 0},
		{"Goexit", Func, 0},
		{"GoroutineProfile", Func, 0},
		{"Gosched", Func, 0},
		{"KeepAlive", Func, 7},
		{"LockOSThread", Func, 0},
		{"MemProfile", Func, 0},
		{"MemProfileRate", Var, 0},
		{"MemProfileRecord", Type, 0},
		{"MemProfileRecord.AllocBytes", Field, 0},
		{"MemProfileRecord.AllocObjects", Field, 0},