It looks like the sentinel doesn't handle fatal death of the child process:
test test_multiprocessing crashed -- Traceback (most recent call last):
File "./Lib/test/regrtest.py", line 1043, in runtest_inner
File "/Users/db3l/buildarea/3.x.bolen-tiger/build/Lib/test/test_multiprocessing.py", line 2189, in test_main
ManagerMixin.manager.start()
File "/Users/db3l/buildarea/3.x.bolen-tiger/build/Lib/multiprocessing/managers.py", line 531, in start
self._address = reader.recv()
File "/Users/db3l/buildarea/3.x.bolen-tiger/build/Lib/multiprocessing/connection.py", line 273, in recv
buf = self._recv_bytes(sentinels=sentinels)
File "/Users/db3l/buildarea/3.x.bolen-tiger/build/Lib/multiprocessing/connection.py", line 430, in _recv_bytes
buf = self._recv(4, sentinels)
File "/Users/db3l/buildarea/3.x.bolen-tiger/build/Lib/multiprocessing/connection.py", line 413, in _recv
raise EOFError
EOFError