Intermittent python.exe crash with iocpreactor/Vista

New submission from ivank <[email protected]>:

If you run
{{{
python C:\Python26\Scripts\trial.py -r iocp -e twisted.test.test_udp.UDPTestCase.testSendPackets
}}}
enough times manually (not with trial -u) (I used up, enter, up enter), python.exe crashes. This happens less than 0.5% of the time; it is about 5 times less likely than #3969.

When I hit this bug, Vista's "Python has stopped working" dialog opens, and then then Vista's  "DEP has stopped this program" balloon opens.

My uneducated guess is memory corruption in iocpsupport.

I tested with Server 2008 SP1, Python 2.6.2 32 bit, Twisted r27226 (built with VS2008).

----------
Type     : defect
Component: core
Keywords : iocp iocpreactor security
Priority : high
Nosy     : 
----------
http://twistedmatrix.com/trac/ticket/3970