I guess this is some kind of race condition.  I see
test_queue fail about 5% of the time (judged by running
./python ../Lib/test/regrtest.py test_queue test_queue
test_queue test_queue ... with a couple of hundred
test_queue's, but I've seen it fail as part of a more
normal test run too).

It's always this failure:

test test_queue failed -- blocking function '<bound
method FailingQueue.put of
<test.test_queue.FailingQueue instance at 0x4041b184>>'
appeared not to block

and then, at least sometimes, you get this traceback:

Exception in thread Thread-3408:
Traceback (most recent call last):
  File
"/home/mwh/src/python/dist/src/Lib/threading.py", line
442, in __bootstrap
    self.run()
  File
"/home/mwh/src/python/dist/src/Lib/test/test_queue.py",
line 23, in run
    self.fn(*self.args)
  File "/home/mwh/src/python/dist/src/Lib/Queue.py",
line 129, in get
    item = self._get()
  File
"/home/mwh/src/python/dist/src/Lib/test/test_queue.py",
line 58, in _get
    return Queue.Queue._get(self)
AttributeError: 'NoneType' object has no attribute 'Queue'

somewhat later, usually while a subsequent test is running.

This is a debug build from CVS as of an hour or so back
on Redhat Linux 9 (so, in particular, with the NPTL
threading libray, not LinuxThreads).