Bug 1084500 - threading._after_fork spews "cannot notify on un-acquired lock" when os.fork is called from a thread
Summary: threading._after_fork spews "cannot notify on un-acquired lock" when os.fork ...
Keywords:
Status: CLOSED EOL
Alias: None
Product: Fedora
Classification: Fedora
Component: python-pthreading
Version: 23
Hardware: Unspecified
OS: Unspecified
unspecified
unspecified
Target Milestone: ---
Assignee: Barak
QA Contact: Fedora Extras Quality Assurance
URL:
Whiteboard: infra
Depends On:
Blocks:
TreeView+ depends on / blocked
 
Reported: 2014-04-04 14:00 UTC by Dan Kenigsberg
Modified: 2016-12-20 12:46 UTC (History)
4 users (show)

Fixed In Version:
Clone Of:
Environment:
Last Closed: 2016-12-20 12:46:37 UTC
Type: Bug
Embargoed:


Attachments (Terms of Use)
reproducer (448 bytes, text/plain)
2014-04-04 14:00 UTC, Dan Kenigsberg
no flags Details

Description Dan Kenigsberg 2014-04-04 14:00:48 UTC
Created attachment 882722 [details]
reproducer

Description of problem:
pthreading.monkey_patch() changes threading.Lock only after threading._MainThread has been initialized with the predefined Lock.

For some reason, when it's time to __stop() the main thread, 
_MainThread.__block.notify_all() fails.

I'm not aware of any side effects of this, but it's ugly and sounds dangerous.

Version-Release number of selected component (if applicable):
pthreading-0.1.3

How reproducible:
100%

Steps to Reproduce:
1. pthreading.monkey_patch()
2. call os.fork from a thread

(see attached reproducer)

Actual results:
Traceback (most recent call last):
  File "fork_exception.py", line 11, in after_fork
    orig_after_fork()
  File "/usr/lib64/python2.7/threading.py", line 1239, in _after_fork
    thread._Thread__stop()
  File "/usr/lib64/python2.7/threading.py", line 874, in __stop
    self.__block.notify_all()
  File "/usr/lib64/python2.7/threading.py", line 409, in notifyAll
    self.notify(len(self.__waiters))
  File "/usr/lib64/python2.7/threading.py", line 386, in notify
    raise RuntimeError("cannot notify on un-acquired lock")
RuntimeError: cannot notify on un-acquired lock
Exception RuntimeError: RuntimeError('cannot notify on un-acquired lock',) in <module 'threading' from '/usr/lib64/python2.7/threading.pyc'> ignored

Expected results:
silence

Comment 2 Fedora End Of Life 2015-05-29 11:27:48 UTC
This message is a reminder that Fedora 20 is nearing its end of life.
Approximately 4 (four) weeks from now Fedora will stop maintaining
and issuing updates for Fedora 20. It is Fedora's policy to close all
bug reports from releases that are no longer maintained. At that time
this bug will be closed as EOL if it remains open with a Fedora  'version'
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Although we aim to fix as many bugs as possible during every release's 
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Comment 3 Fedora End Of Life 2016-11-24 11:08:54 UTC
This message is a reminder that Fedora 23 is nearing its end of life.
Approximately 4 (four) weeks from now Fedora will stop maintaining
and issuing updates for Fedora 23. It is Fedora's policy to close all
bug reports from releases that are no longer maintained. At that time
this bug will be closed as EOL if it remains open with a Fedora  'version'
of '23'.

Package Maintainer: If you wish for this bug to remain open because you
plan to fix it in a currently maintained version, simply change the 'version' 
to a later Fedora version.

Thank you for reporting this issue and we are sorry that we were not 
able to fix it before Fedora 23 is end of life. If you would still like 
to see this bug fixed and are able to reproduce it against a later version 
of Fedora, you are encouraged  change the 'version' to a later Fedora 
version prior this bug is closed as described in the policy above.

Although we aim to fix as many bugs as possible during every release's 
lifetime, sometimes those efforts are overtaken by events. Often a 
more recent Fedora release includes newer upstream software that fixes 
bugs or makes them obsolete.

Comment 4 Fedora End Of Life 2016-12-20 12:46:37 UTC
Fedora 23 changed to end-of-life (EOL) status on 2016-12-20. Fedora 23 is
no longer maintained, which means that it will not receive any further
security or bug fix updates. As a result we are closing this bug.

If you can reproduce this bug against a currently maintained version of
Fedora please feel free to reopen this bug against that version. If you
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bug.

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