访问Lock

Question

我想在子进程中使用Lock来处理文件。当我在初始化程序中访问Lock时，Pool对初始化程序进行无限递归调用。

from multiprocessing import Lock, get_context


class MyClass(object):

    @classmethod
    def run_mp(cls, jobs):
        context = get_context('spawn')
        w_lock = Lock()
        with context.Pool(1, initializer=cls._mp_init, initargs=(w_lock, )) as pool:
            res = pool.map(cls._execute_job, jobs)
            pool.close()

    @classmethod
    def _mp_init(cls, w_lock):
        # global weights_lock
        # weights_lock = w_lock
        print('weights lock')
        print(w_lock)  # this line causes infinite calls to this method

    @classmethod
    def _execute_job(cls, job):
        pass


if __name__ == '__main__':
    jobs = [1]
    mc = MyClass()
    mc.run_mp(jobs)

预期产量

我在本地计算机上获得了预期的输出-mac_os，python3.7

weights lock
<Lock(owner=unknown)>

错误的输出

当我在gcloud（Linux 18.04，python 3.6）的linux实例上运行此命令时，我得到了

weights lock
weights lock
weights lock
weights lock
weights lock
# ... infinitely

如果我在print(w_lock)方法中将_init_mp注释掉，那么输出将再次如预期那样

weight lock

因此，基本上，当我尝试访问w_lock时，它会进入_init_mp的无限递归调用中。

我尝试在具有相同行为的不同glcoud实例上运行此程序。

我不明白为什么在Linux上访问锁会导致这种行为。有什么解释吗？