A different hang on "AMD64 Windows7 SP1 3.4/" buildbot:

http://buildbot.python.org/all/builders/AMD64%20Windows7%20SP1%203.4/builds/805/steps/test/logs/stdio

This build is also related to the changeset d3804307cce44f7f02e38166daf6d8227aa45021: "IocpProactor.close() must not cancel pending _WaitCancelFuture futures".

IMO it's not a new bug, it's just that it was not seen before. I may be related to the issue #23293.

[390/390/1] test_asyncio
Timeout (1:00:00)!
Current thread 0x000005c8 (most recent call first):
  File "C:\buildbot.python.org\3.4.kloth-win64\build\lib\asyncio\windows_events.py", line 620 in _unregister
  File "C:\buildbot.python.org\3.4.kloth-win64\build\lib\asyncio\windows_events.py", line 196 in _unregister_wait_cb
  File "C:\buildbot.python.org\3.4.kloth-win64\build\lib\asyncio\windows_events.py", line 212 in _unregister_wait
  File "C:\buildbot.python.org\3.4.kloth-win64\build\lib\asyncio\windows_events.py", line 152 in set_result
  File "C:\buildbot.python.org\3.4.kloth-win64\build\lib\asyncio\windows_events.py", line 674 in _poll
  File "C:\buildbot.python.org\3.4.kloth-win64\build\lib\asyncio\windows_events.py", line 389 in select
  File "C:\buildbot.python.org\3.4.kloth-win64\build\lib\asyncio\base_events.py", line 1081 in _run_once
  File "C:\buildbot.python.org\3.4.kloth-win64\build\lib\asyncio\base_events.py", line 258 in run_forever
  File "C:\buildbot.python.org\3.4.kloth-win64\build\lib\asyncio\base_events.py", line 286 in run_until_complete
  File "C:\buildbot.python.org\3.4.kloth-win64\build\lib\test\test_asyncio\test_subprocess.py", line 211 in test_pause_reading
  File "C:\buildbot.python.org\3.4.kloth-win64\build\lib\unittest\case.py", line 577 in run
  File "C:\buildbot.python.org\3.4.kloth-win64\build\lib\unittest\case.py", line 625 in __call__
  File "C:\buildbot.python.org\3.4.kloth-win64\build\lib\unittest\suite.py", line 125 in run
  File "C:\buildbot.python.org\3.4.kloth-win64\build\lib\unittest\suite.py", line 87 in __call__
  File "C:\buildbot.python.org\3.4.kloth-win64\build\lib\unittest\suite.py", line 125 in run
  File "C:\buildbot.python.org\3.4.kloth-win64\build\lib\unittest\suite.py", line 87 in __call__
  File "C:\buildbot.python.org\3.4.kloth-win64\build\lib\unittest\suite.py", line 125 in run
  File "C:\buildbot.python.org\3.4.kloth-win64\build\lib\unittest\suite.py", line 87 in __call__
  File "C:\buildbot.python.org\3.4.kloth-win64\build\lib\unittest\suite.py", line 125 in run
  File "C:\buildbot.python.org\3.4.kloth-win64\build\lib\unittest\suite.py", line 87 in __call__
  File "C:\buildbot.python.org\3.4.kloth-win64\build\lib\unittest\runner.py", line 168 in run
  File "C:\buildbot.python.org\3.4.kloth-win64\build\lib\test\support\__init__.py", line 1769 in _run_suite
  File "C:\buildbot.python.org\3.4.kloth-win64\build\lib\test\support\__init__.py", line 1803 in run_unittest
  File "C:\buildbot.python.org\3.4.kloth-win64\build\lib\test\regrtest.py", line 1279 in test_runner
  File "C:\buildbot.python.org\3.4.kloth-win64\build\lib\test\regrtest.py", line 1280 in runtest_inner
  File "C:\buildbot.python.org\3.4.kloth-win64\build\lib\test\regrtest.py", line 967 in runtest
  File "C:\buildbot.python.org\3.4.kloth-win64\build\lib\test\regrtest.py", line 532 in main
  File "C:\buildbot.python.org\3.4.kloth-win64\build\lib\test\regrtest.py", line 1564 in main_in_temp_cwd
  File "C:\buildbot.python.org\3.4.kloth-win64\build\lib\test\regrtest.py", line 1589 in <module>
  File "C:\buildbot.python.org\3.4.kloth-win64\build\lib\runpy.py", line 85 in _run_code
  File "C:\buildbot.python.org\3.4.kloth-win64\build\lib\runpy.py", li