[Bug 672209] Re: [SRU] multiprocessing module dysfunctional

[Launchpad Bug Tracker]

** Branch linked: lp:ubuntu/maverick-proposed/python2.7

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https://bugs.launchpad.net/bugs/672209

Title:
  [SRU] multiprocessing module dysfunctional

Status in “python2.7” package in Ubuntu:
  Fix Released
Status in “python2.7” source package in Maverick:
  Fix Committed

Bug description:
  * Impact of bug: This bug will prevent common usage of the multiprocessing module in Python 2.7 on Maverick.
  * Fix: The bug was addressed in the current version of Ubuntu with a no-change rebuild. Since the original problem was caused by kernel configuration on the buildd's, and (as verified by PPA build) this has been rectified, a simple rebuild is all that's needed
  * TEST CASE: see above or: $ python2.7 -c 'from _multiprocessing import SemLock'
  * I don't see much chance for regression. Code which relies on multiprocessing in Python 2.7 can't currently run on Maverick. This rebuild will only re-enable standard Python functionality.
  Binary package hint: python2.7

  On Maverick with python2.7 (2.7-6 deb version), the multiprocessing
  module fails to operate:

  python2.7 -c 'import multiprocessing; multiprocessing.Pool()'
  Traceback (most recent call last):
    File "<string>", line 1, in <module>
    File "/usr/lib/python2.7/multiprocessing/__init__.py", line 227, in Pool
      return Pool(processes, initializer, initargs, maxtasksperchild)
    File "/usr/lib/python2.7/multiprocessing/pool.py", line 89, in __init__
      self._setup_queues()
    File "/usr/lib/python2.7/multiprocessing/pool.py", line 181, in _setup_queues
      from .queues import SimpleQueue
    File "/usr/lib/python2.7/multiprocessing/queues.py", line 22, in <module>
      from multiprocessing.synchronize import Lock, BoundedSemaphore, Semaphore, Condition
    File "/usr/lib/python2.7/multiprocessing/synchronize.py", line 33, in <module>
      " function, see issue 3770.")
  ImportError: This platform lacks a functioning sem_open implementation, therefore, the required synchronization primitives needed will not function, see issue 3770.