golang

	for _, v := range resultObjects {
		sd, exist := m[v.Endpoint]
		if !exist {
                        sd := new(SavedData) // sd = new(SavedData)
			sd.Ip = v.Endpoint
			sd.StartTime = time.Unix(start, 0)
			sd.EndTime = time.Unix(end, 0)

			m[v.Endpoint] = sd
		}
		...
  	        ...
                ...

		sd.CpuMax = float64(max)
		sd.CpuMin = min

		m[v.Endpoint] = sd
	}

跑这段代码会出现这个问题：

panic: runtime error: invalid memory address or nil pointer dereference

因为忽略了作用域