t.Logf("Inuse %vMB for stack mem", inuse>>20)
	if inuse > 4<<20 {
		t.Fatalf("Stack inuse: want %v, got %v", 4<<20, inuse)
	}
}

// Test stack growing in different contexts.
func TestStackGrowth(t *testing.T) {
	if *flagQuick {
		t.Skip("-quick")
	}

	var wg sync.WaitGroup

	// in a normal goroutine
	var growDuration time.Duration // For debugging failures
	wg.Add(1)
	go func() {