// 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},

pkg runtime, func GOMAXPROCS(int) int
pkg runtime, func GOROOT() string
pkg runtime, func Goexit()
pkg runtime, func GoroutineProfile([]StackRecord) (int, bool)
pkg runtime, func Gosched()
pkg runtime, func LockOSThread()
pkg runtime, func MemProfile([]MemProfileRecord, bool) (int, bool)
pkg runtime, func NumCPU() int
pkg runtime, func NumCgoCall() int64
pkg runtime, func NumGoroutine() int