There have been a number of EINTR-releated issues reported in the past, some unique to BSD-based systems and/or OS X; see for example, Issue9867 and Issue12268.  I don't know that any of them specifically addressed problems with writes to Python 2 file objects.  FWIW, with your test case, I'm not able to reproduce a failure on 10.9.3 using python.org 2.7.8 or 2.7.3 or with the system 2.7.5.  And, with a modified print(), I didn't see a failure with python.org 3.4.1, either.  Can you say more about the origins of your Python 2.7.2?  Have you tried with a current 2.7.8?  How quickly does the test fail, e.g. after how many iterations?