New submission from Itay Brandes :
multiprocessing.dummy crashes when attempting to create a ThreadPool from a
Thread.
The following code will crush on 2.7.3:
import multiprocessing.dummy
import threading
class Worker(threading.Thread):
def __init__(self):
threading.Thread.__init__(self)
def run(self):
poll = multiprocessing.dummy.Pool(5)
print str(poll)
w = Worker()
w.start()
will crush with the following traceback:
poll = multiprocessing.dummy.Pool(5)
File "C:\Python27\lib\multiprocessing\dummy\__init__.py", line 150, in Pool
return ThreadPool(processes, initializer, initargs)
File "C:\Python27\lib\multiprocessing\pool.py", line 685, in __init__
Pool.__init__(self, processes, initializer, initargs)
File "C:\Python27\lib\multiprocessing\pool.py", line 136, in __init__
self._repopulate_pool()
File "C:\Python27\lib\multiprocessing\pool.py", line 199, in _repopulate_pool
w.start()
File "C:\Python27\lib\multiprocessing\dummy\__init__.py", line 73, in start
self._parent._children[self] = None
AttributeError: 'Worker' object has no attribute '_children'
If you have access to the thread itself, you can set the _children attribute
youself (w._children = weakref.WeakKeyDictionary()), but it is not possible
with threads different from threading.thread (Such as PyQt4's QThread thread,
which is essential for GUI programming).
The fix that I found is to edit the
Python27\Lib\multiprocessing\dummy\__init__.py file. The crashing code is line
number 73.
This line should be nested in an if block:
if hasattr(self._parent, '_children'):
self._parent._children[self] = None
That way the code is fixed.
Thanks!
--
components: None
messages: 161339
nosy: Itay.Brandes
priority: normal
severity: normal
status: open
title: multiprocessing.dummy craches when self._parent._children does not exist
type: crash
versions: Python 2.7
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<http://bugs.python.org/issue14881>
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