EXC_BAD_ACCESS的查找方法
1. 配置NSZombieEnabled环境变量
2. 加入MallocStackLogging环境变量启用malloc记录
当错误发生时，在终端执行:
malloc_history ${App_PID} ${Object_instance_addr}
2011-02-27 14:56:42.042 app[3943:307] *** -[CFString retain]: message sent to deallocated instance 0x15294b60
>malloc_history 3943 0x15294b60