python多处理：一些函数在完成后不返回（队列材料太大）

I am using multiprocessing's Process and Queue. I start several functions in parallel and most behave nicely: they finish, their output goes to their Queue, and they show up as .is_alive() == False. But for some reason a couple of functions are not behaving. They always show .is_alive() == True, even after the last line in the function (a print statement saying "Finished") is complete. This happens regardless of the set of functions I launch, even it there's only one. If not run in parallel, the functions behave fine and return normally. What I am using multiprocessing's Process and Queue.