[New-bugs-announce] [issue15914] multiprocessing.SyncManager connection hang

Sean B. Palmer report at bugs.python.org
Mon Sep 10 23:29:48 CEST 2012

New submission from Sean B. Palmer:


import multiprocessing
manager = multiprocessing.Manager()
namespace = manager.Namespace()
print("create.py complete")


import create
print("run.py complete")

Correct behaviour occurs for create.py:

$ python3 create.py
create.py complete

INCORRECT behaviour occurs for run.py:

$ python3 run.py

No output, because it hangs. On SIGINT:

^CTraceback (most recent call last):
  File "run.py", line 1, in <module>
    import create
  File "[...]/create.py", line 7, in <module>
  File "[...]/create.py", line 5, in test
    namespace = manager.Namespace()
  File "/Library/Frameworks/Python.framework/Versions/3.2/lib/python3.2/multiprocessing/managers.py", line 670, in temp
    token, exp = self._create(typeid, *args, **kwds)
  File "/Library/Frameworks/Python.framework/Versions/3.2/lib/python3.2/multiprocessing/managers.py", line 568, in _create
    conn = self._Client(self._address, authkey=self._authkey)
  File "/Library/Frameworks/Python.framework/Versions/3.2/lib/python3.2/multiprocessing/connection.py", line 175, in Client
    answer_challenge(c, authkey)
  File "/Library/Frameworks/Python.framework/Versions/3.2/lib/python3.2/multiprocessing/connection.py", line 412, in answer_challenge
    message = connection.recv_bytes(256)         # reject large message

$ python3
Python 3.2.3 (v3.2.3:3d0686d90f55, Apr 10 2012, 11:25:50) 
[GCC 4.2.1 (Apple Inc. build 5666) (dot 3)] on darwin

This appears to be a duplicate of this *closed* bug:


This was closed because nobody could reproduce the behaviour on Python 3. I have reproduced it, but I don't know how to reopen that bug, so I'm filing this one. The test case in 7474 also fails for me.

messages: 170240
nosy: palmer
priority: normal
severity: normal
status: open
title: multiprocessing.SyncManager connection hang
type: crash
versions: Python 3.2

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