// (Perhaps c.Wait hadn't been called, or perhaps it happened to race with
			// c.ctx being canceled.) Don't inject a needless error.
		} else {
			err = wrappedError{
				prefix: "exec: canceling Cmd",
				err:    interruptErr,
			}
		}
	}
	if c.WaitDelay == 0 {
		resultc <- ctxResult{err: err}
		return
	}

	timer := time.NewTimer(c.WaitDelay)
	select {

			// Panic instead of calling t.Fatal so that we get a goroutine dump.
			// We want to know exactly what the os/exec goroutines got stuck on.
			debug.SetTraceback("system")
			panic("canceling context did not stop program")
		}

		// Back off exponentially (up to 1-second sleeps) to give the OS time to
		// terminate the process.
		delay *= 2
		if delay > 1*time.Second {