Closing this issue after having verified that the issue can no longer be reproduced on the systems mentioned (Ubuntu 10.04 or OSX).  Related issues such as issue9205 have been addressed elsewhere and other possibly related issues such as issue22393 are being tracked separately.  It appears Jesse's patches in 2010 (though not explicitly added to this issue here) have indeed addressed this issue.


Using OS X 10.10:
Using Greg's original test script (from his first post), I ran the script 100 times (via shell script loop) but was unable to provoke the issue on OS X 10.10 using either the Anaconda build of Python 2.7.9 or a local build from the default (3.5.0a1+) branch.

Using Matt Walker's supplied test script (from a much later post here), I ran his script 100 times in tight succession but was unable to provoke the issue on OS X 10.10 using either the Anaconda build of Python 2.7.9 or a local build from the default (3.5.0a1+) branch.  Side note:  running Matt's test script kinda takes a while ("time.sleep(10)" seriously?), especially at 100 iterations.



Using Ubuntu 10.04 (64-bit):
I installed Ubuntu 10.04.4 64-bit Server in a VM and repeated the above test sequences with those two scripts using the stock Python 2.6.5, locally built 2.7 branch, and locally built default (3.5) branch versions.  Summary:
* At 100 iterations I was still unable to provoke the issue with Greg's script using 2.6.5, 2.7.9+, or 3.5.0a1+.
* Matt's script leverages functionality only introduced in 2.7 and so could not be run as-is with 2.6.5.
* At 100 iterations I was still unable to provoke the issue with Matt's script using 2.7.9+ or 3.5.0a1+.



Even if it's a little late in saying:  thanks goes to the reporters, Greg and Matt, and to Jesse for implementing the fix.