Recent failure (17 days ago) on the master branch:

https://travis-ci.org/python/cpython/jobs/396258134

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ERROR: testSendmsgTimeout (test.test_socket.SendmsgSCTPStreamTest)
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Traceback (most recent call last):
  File "/home/travis/build/python/cpython/Lib/test/test_socket.py", line 314, in _tearDown
    raise exc
  File "/home/travis/build/python/cpython/Lib/test/test_socket.py", line 332, in clientRun
    test_func()
  File "/home/travis/build/python/cpython/Lib/test/test_socket.py", line 2648, in _testSendmsgTimeout
    self.sendmsgToServer([b"a"*512])
  File "/home/travis/build/python/cpython/Lib/test/test_socket.py", line 2337, in sendmsgToServer
    *(args + self.sendmsg_to_server_defaults[len(args):]))
OSError: [Errno 12] Cannot allocate memory
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FAIL: testSendmsgDontWait (test.test_socket.SendmsgSCTPStreamTest)
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Traceback (most recent call last):
  File "/home/travis/build/python/cpython/Lib/test/test_socket.py", line 314, in _tearDown
    raise exc
  File "/home/travis/build/python/cpython/Lib/test/test_socket.py", line 332, in clientRun
    test_func()
  File "/home/travis/build/python/cpython/Lib/test/test_socket.py", line 2672, in _testSendmsgDontWait
    (errno.EAGAIN, errno.EWOULDBLOCK))
AssertionError: 12 not found in (11, 11)