While trying to reproduce issue #11870 using "gdb -args ./python Lib/test/regrtest.py -F -v --timeout=600 test_threading", I had the following error on Linux:
----------------------
test_default_timeout (test.test_threading.BarrierTests) ... [Thread 0x7ffff1acf700 (LWP 27178) exited]
[New Thread 0x7ffff1acf700 (LWP 27181)]
[New Thread 0x7ffff12ce700 (LWP 27182)]
[New Thread 0x7ffff3c99700 (LWP 27183)]
[New Thread 0x7ffff325a700 (LWP 27184)]
Unhandled exception in thread started by <function task at 0x1302340>
Unhandled exception in thread started by <function task at 0x1302340>
Unhandled exception in thread started by <function task at 0x1302340>
Traceback (most recent call last):
Unhandled exception in thread started by <function task at 0x1302340>
  File "/home/haypo/prog/HG/cpython/Lib/test/lock_tests.py", line 37, in task
Traceback (most recent call last):
Traceback (most recent call last):
  File "/home/haypo/prog/HG/cpython/Lib/test/lock_tests.py", line 37, in task
Traceback (most recent call last):
  File "/home/haypo/prog/HG/cpython/Lib/test/lock_tests.py", line 37, in task
    f()
    f()
  File "/home/haypo/prog/HG/cpython/Lib/test/lock_tests.py", line 37, in task
  File "/home/haypo/prog/HG/cpython/Lib/test/lock_tests.py", line 838, in f
ERROR
----------------------

----------------------
ERROR: test_default_timeout (test.test_threading.BarrierTests)

Traceback (most recent call last):
  File "/home/haypo/prog/HG/cpython/Lib/test/lock_tests.py", line 843, in test_default_timeout
    self.run_threads(f)
  File "/home/haypo/prog/HG/cpython/Lib/test/lock_tests.py", line 672, in run_threads
    f()
  File "/home/haypo/prog/HG/cpython/Lib/test/lock_tests.py", line 838, in f
    i = barrier.wait()
  File "/home/haypo/prog/HG/cpython/Lib/threading.py", line 472, in wait
    self._enter() # Block while the barrier drains.
  File "/home/haypo/prog/HG/cpython/Lib/threading.py", line 496, in _enter
    raise BrokenBarrierError
threading.BrokenBarrierError
----------------------

The error occured on:

 * Ubuntu 10.04
 * Python 3.3 (2127df2c972e)
 * Intel(R) Core(TM)2 Quad  CPU   Q9300  @ 2.50GHz
 * 4 GB of memory