Comment 3 for bug 1441933

Here is a full stacktrace: http://paste.ubuntu.com/10781115/

(I just hacked /usr/lib/python2.7/dist-packages/crochet/_eventloop.py to call result.printTraceback() —that's right, that's the kind of thing you have to do to get Twisted to give you a (vaguely) meaningful stacktrace).