s390x RHEL7 LTO 3.x:
https://buildbot.python.org/all/#/builders/402/builds/979

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0:02:00 load avg: 5.14 [193/427/2] test_pickletools crashed (Exit code -11) -- running: test_unparse (30.6 sec), test_concurrent_futures (1 min 56 sec), test_multiprocessing_spawn (43.2 sec)
Fatal Python error: Segmentation fault

Current thread 0x000003ffb8e77700 (most recent call first):
  File "/home/dje/cpython-buildarea/3.x.edelsohn-rhel-z.lto/build/Lib/test/pickletester.py", line 3304 in __getattr__
  File "/home/dje/cpython-buildarea/3.x.edelsohn-rhel-z.lto/build/Lib/test/pickletester.py", line 3305 in __getattr__
  File "/home/dje/cpython-buildarea/3.x.edelsohn-rhel-z.lto/build/Lib/test/pickletester.py", line 3305 in __getattr__
  (...)
  File "/home/dje/cpython-buildarea/3.x.edelsohn-rhel-z.lto/build/Lib/test/pickletester.py", line 3305 in __getattr__
  File "/home/dje/cpython-buildarea/3.x.edelsohn-rhel-z.lto/build/Lib/test/pickletester.py", line 3305 in __getattr__
  File "/home/dje/cpython-buildarea/3.x.edelsohn-rhel-z.lto/build/Lib/test/pickletester.py", line 3305 in __getattr__
  ...

Extension modules: _testcapi, _testbuffer (total: 2)
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and

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test_instance_dispatch_table (test.test_pickle.CDispatchTableTests) ... ok
test_appends_on_non_lists (test.test_pickle.CDumpPickle_LoadPickle) ... ok
test_attribute_name_interning (test.test_pickle.CDumpPickle_LoadPickle) ... ok
Fatal Python error: Segmentation fault

Current thread 0x000003ff80377700 (most recent call first):
  File "/home/dje/cpython-buildarea/3.x.edelsohn-rhel-z.lto/build/Lib/test/pickletester.py", line 3305 in __getattr__
  File "/home/dje/cpython-buildarea/3.x.edelsohn-rhel-z.lto/build/Lib/test/pickletester.py", line 3305 in __getattr__
  File "/home/dje/cpython-buildarea/3.x.edelsohn-rhel-z.lto/build/Lib/test/pickletester.py", line 3305 in __getattr__
  (...)
  File "/home/dje/cpython-buildarea/3.x.edelsohn-rhel-z.lto/build/Lib/test/pickletester.py", line 3305 in __getattr__
  File "/home/dje/cpython-buildarea/3.x.edelsohn-rhel-z.lto/build/Lib/test/pickletester.py", line 3305 in __getattr__
  File "/home/dje/cpython-buildarea/3.x.edelsohn-rhel-z.lto/build/Lib/test/pickletester.py", line 3305 in __getattr__
  ...

Extension modules: _testcapi, _testbuffer (total: 2)
--------------------