for atomic.LoadUint64(&flag) == 0 {
			runtime.Gosched()
		}
		done <- true
	}()
	time.Sleep(50 * time.Millisecond)
	atomic.StoreUint64(&flag, 1)
	<-done
}

func TestTracebackAll(t *testing.T) {
	// With gccgo, if a profiling signal arrives at the wrong time
	// during traceback, it may crash or hang. See issue #29448.
	f, err := os.CreateTemp("", "proftraceback")
	if err != nil {