test_open() of test_eintr hangs randomly on x86-64 El Capitan 3.x buildbot. test_eintr failed but then passed when run again.

pythoninfo:

platform.platform: Darwin-15.6.0-x86_64-i386-64bit  # macOS 10.11 (El Capitan)


https://buildbot.python.org/all/#/builders/93/builds/1574

test_all (test.test_eintr.EINTRTests) ... FAIL

======================================================================
FAIL: test_all (test.test_eintr.EINTRTests)
----------------------------------------------------------------------
Traceback (most recent call last):
  File "/Users/buildbot/buildarea/3.x.billenstein-elcapitan/build/Lib/test/test_eintr.py", line 18, in test_all
    script_helper.assert_python_ok("-u", tester)
  File "/Users/buildbot/buildarea/3.x.billenstein-elcapitan/build/Lib/test/support/script_helper.py", line 157, in assert_python_ok
    return _assert_python(True, *args, **env_vars)
  File "/Users/buildbot/buildarea/3.x.billenstein-elcapitan/build/Lib/test/support/script_helper.py", line 143, in _assert_python
    res.fail(cmd_line)
  File "/Users/buildbot/buildarea/3.x.billenstein-elcapitan/build/Lib/test/support/script_helper.py", line 70, in fail
    raise AssertionError("Process return code is %d\n"
AssertionError: Process return code is 1
command line: ['/Users/buildbot/buildarea/3.x.billenstein-elcapitan/build/python.exe', '-X', 'faulthandler', '-I', '-u', '/Users/buildbot/buildarea/3.x.billenstein-elcapitan/build/Lib/test/eintrdata/eintr_tester.py']

stdout:
---

---

stderr:
---
........ss.s.ss.Timeout (0:10:00)!
Thread 0x00007fff7c082000 (most recent call first):
  File "/Users/buildbot/buildarea/3.x.billenstein-elcapitan/build/Lib/test/eintrdata/eintr_tester.py", line 349 in python_open
  File "/Users/buildbot/buildarea/3.x.billenstein-elcapitan/build/Lib/test/eintrdata/eintr_tester.py", line 345 in _test_open
  File "/Users/buildbot/buildarea/3.x.billenstein-elcapitan/build/Lib/test/support/__init__.py", line 596 in wrapper
  File "/Users/buildbot/buildarea/3.x.billenstein-elcapitan/build/Lib/test/eintrdata/eintr_tester.py", line 353 in test_open
  File "/Users/buildbot/buildarea/3.x.billenstein-elcapitan/build/Lib/unittest/case.py", line 642 in run
  File "/Users/buildbot/buildarea/3.x.billenstein-elcapitan/build/Lib/unittest/case.py", line 702 in __call__
  File "/Users/buildbot/buildarea/3.x.billenstein-elcapitan/build/Lib/unittest/suite.py", line 122 in run
  File "/Users/buildbot/buildarea/3.x.billenstein-elcapitan/build/Lib/unittest/suite.py", line 84 in __call__
  File "/Users/buildbot/buildarea/3.x.billenstein-elcapitan/build/Lib/unittest/suite.py", line 122 in run
  File "/Users/buildbot/buildarea/3.x.billenstein-elcapitan/build/Lib/unittest/suite.py", line 84 in __call__
  File "/Users/buildbot/buildarea/3.x.billenstein-elcapitan/build/Lib/unittest/runner.py", line 176 in run
  File "/Users/buildbot/buildarea/3.x.billenstein-elcapitan/build/Lib/unittest/main.py", line 271 in runTests
  File "/Users/buildbot/buildarea/3.x.billenstein-elcapitan/build/Lib/unittest/main.py", line 101 in __init__
  File "/Users/buildbot/buildarea/3.x.billenstein-elcapitan/build/Lib/test/eintrdata/eintr_tester.py", line 527 in <module>
---

----------------------------------------------------------------------

Ran 1 test in 605.488s

FAILED (failures=1)
Warning -- files was modified by test_eintr
  Before: []
  After:  ['@test_57532_tmp'] 
test test_eintr failed