Error on some forked thread termination in python threading module

[Charles R. Harwood]

I'd like for the fix to python issue 14308 to be ported to python2.7 in Ubuntu Precise.
http://bugs.python.org/issue14308

As near as I can tell, it affects python 2.7 threading.Thread threads which have were are created, call currentThread(), are then forked, and then terminate.

For my purposes, it is affecting some code I wrote which does spawns processes to run simple shell scripts in the background. It also seems to have affected various Django projects as well as Duplicity as per https://bugs.launchpad.net/duplicity/+bug/946993. As I read that ticket, it was fixed via a workaround in Duplicity/Debbugs? It seems to me that this is really a Python2.7 bug.

I was able to easily reproduce this bug with this small test case as per the python bug ticket on Ubuntu Precise Server:
<code>
#!/usr/bin/python
import os
import thread
import threading
import time

def t():
    threading.currentThread() # Populate threading._active with a DummyThread
    time.sleep(3)

thread.start_new_thread(t, ())
time.sleep(1)

pid = os.fork()
if pid == 0:
    os._exit(0)

os.waitpid(pid, 0)
</code>

The fix is a simple two-line patch to threading.py implemented by the fix for python bug 14308. I have also attached that, again from http://bugs.python.org/issue14308.

As far as I can tell, this has not made its way from upstream to Precise. My sincerest apologies if this is reported elsewhere or my report is somehow inappropriate.

[Ubuntu Foundations Team Bug Bot (crichton)]

The attachment "Patch from Python Bug 14308" of this bug report has been identified as being a patch. The ubuntu-reviewers team has been subscribed to the bug report so that they can review the patch. In the event that this is in fact not a patch you can resolve this situation by removing the tag 'patch' from the bug report and editing the attachment so that it is not flagged as a patch. Additionally, if you are member of the ubuntu-reviewers team please also unsubscribe the team from this bug report.

[This is an automated message performed by a Launchpad user owned by Brian Murray. Please contact him regarding any issues with the action taken in this bug report.]

[Matthias Klose (doko)]

fixed in quantal and raring

[Chris Halse Rogers (raof)]

Hello Charles, or anyone else affected,

Accepted python2.7 into precise-proposed. The package will build now and be available at http://launchpad.net/ubuntu/+source/python2.7/2.7.3-0ubuntu3.2 in a few hours, and then in the -proposed repository.

Please help us by testing this new package. See https://wiki.ubuntu.com/Testing/EnableProposed for documentation how to enable and use -proposed. Your feedback will aid us getting this update out to other Ubuntu users.

If this package fixes the bug for you, please add a comment to this bug, mentioning the version of the package you tested, and change the tag from verification-needed to verification-done. If it does not fix the bug for you, please add a comment stating that, and change the tag to verification-failed. In either case, details of your testing will help us make a better decision.

Further information regarding the verification process can be found at https://wiki.ubuntu.com/QATeam/PerformingSRUVerification . Thank you in advance!

[Colin Watson (cjwatson)]

This seems to be doing the right thing; no exception now with the provided test case.

[Scott Kitterman (kitterman)]

The verification of this Stable Release Update has completed successfully and the package has now been released to -updates. Subsequently, the Ubuntu Stable Release Updates Team is being unsubscribed and will not receive messages about this bug report. In the event that you encounter a regression using the package from -updates please report a new bug using ubuntu-bug and tag the bug report regression-update so we can easily find any regresssions.

[Launchpad Janitor (janitor)]

This bug was fixed in the package python2.7 - 2.7.3-0ubuntu3.2

---------------
python2.7 (2.7.3-0ubuntu3.2) precise-proposed; urgency=low

  * Backport fix for issue #14308. Fix an exception when a "dummy" thread is
    in the threading module's active list after a fork(). LP: #1100343.
  * Remove dangling symlink in pkgconfig. LP: #1088771.
  * Make python2.7{,-minimal,-dbg} Multi-Arch: allowed. LP: #1130709.
 -- Matthias Klose <email address hidden> Thu, 28 Mar 2013 12:40:39 +0100