Occasional core-dump on dispy shutdown

[UnitedMarsupials-zz]

This happens very rarely, but it does happen on occasion...

...
2019-03-05 11:50:16 dispy - Closing node 10.92.161.42 for archive / 1551804595176
2019-03-05 11:50:16 dispy - Closing node 10.92.161.39 for archive / 1551804595176
2019-03-05 11:50:16 dispy - Closing node 10.92.161.9 for archive / 1551804595176
2019-03-05 11:50:16 dispy - Closing node 10.92.161.36 for archive / 1551804595176
2019-03-05 11:50:16 dispy - Closing node 10.92.161.27 for archive / 1551804595176
2019-03-05 11:50:16 archiver - Processing finished, 0 failures
2019-03-05 11:50:16 dispy - Shutting down scheduler ...
2019-03-05 11:50:16 dispy - Scheduler quitting: 0
2019-03-05 11:50:16 dispy - Scheduler quit
2019-03-05 11:50:16 pycos - terminating task !timer_proc/39422296 (daemon)
Fatal Python error: could not acquire lock for <_io.BufferedWriter name='<stdout>'> at interpreter shutdown, possibly due to daemon threads

Thread 0x00007f18e7a3c700 (most recent call first):
  File "/app/local/lib/python3.6/site-packages/pycos/__init__.py", line 166 in log
  File "/app/local/lib/python3.6/site-packages/pycos/__init__.py", line 3821 in _schedule
  File "/app/local/lib/python3.6/threading.py", line 864 in run
  File "/app/local/lib/python3.6/threading.py", line 916 in _bootstrap_inner
  File "/app/local/lib/python3.6/threading.py", line 884 in _bootstrap

Current thread 0x00007f18f3f5f740 (most recent call first):
Aborted (core dumped)

According to gdb, the crash stack is:

#0  0x00007f18f3097207 in raise () from /lib64/libc.so.6
#1  0x00007f18f30988f8 in abort () from /lib64/libc.so.6
#2  0x0000000000428232 in Py_FatalError (msg=<optimized out>) at Python/pylifecycle.c:1481
#3  0x00000000004390a2 in _enter_buffered_busy (self=self@entry=0x1e13ac8) at ./Modules/_io/bufferedio.c:309
#4  0x000000000052811a in buffered_flush () at Python/thread_pthread.h:420
#5  0x00000000004e36ea in _PyCFunction_FastCallDict () at Objects/methodobject.c:192
#6  0x00000000004a9d9e in _PyObject_FastCallDict () at Objects/abstract.c:2313
#7  0x000000000050d72e in callmethod (is_size_t=1, va=0x7ffd8b54f100, format=0x0, func=0x258e678) at Objects/abstract.c:2583
#8  _PyObject_CallMethodId_SizeT () at Objects/abstract.c:2685
#9  0x00000000004e36ea in _PyCFunction_FastCallDict () at Objects/methodobject.c:192
#10 0x00000000004a9d9e in _PyObject_FastCallDict () at Objects/abstract.c:2313
#11 0x000000000050d8ce in callmethod (is_size_t=0, va=0x7ffd8b54f2a0, format=0x0, func=0x7f18e004b3b8) at Objects/abstract.c:2583
#12 _PyObject_CallMethodId () at Objects/abstract.c:2640
#13 0x00000000005b7e2c in flush_std_files () at Python/pylifecycle.c:511
#14 0x000000000042822d in Py_FatalError (msg=<optimized out>) at Python/pylifecycle.c:1460
#15 0x00000000004390a2 in _enter_buffered_busy (self=self@entry=0x1e13ac8) at ./Modules/_io/bufferedio.c:309
#16 0x000000000052811a in buffered_flush () at Python/thread_pthread.h:420
#17 0x00000000004e36ea in _PyCFunction_FastCallDict () at Objects/methodobject.c:192
#18 0x00000000004a9d9e in _PyObject_FastCallDict () at Objects/abstract.c:2313
#19 0x000000000050d72e in callmethod (is_size_t=1, va=0x7ffd8b54f500, format=0x0, func=0x2637aa8) at Objects/abstract.c:2583
#20 _PyObject_CallMethodId_SizeT () at Objects/abstract.c:2685
#21 0x00000000004e36ea in _PyCFunction_FastCallDict () at Objects/methodobject.c:192
#22 0x00000000004a9d9e in _PyObject_FastCallDict () at Objects/abstract.c:2313
#23 0x000000000050d8ce in callmethod (is_size_t=0, va=0x7ffd8b54f6a0, format=0x0, func=0x7f18e0043cc8) at Objects/abstract.c:2583
#24 _PyObject_CallMethodId () at Objects/abstract.c:2640
#25 0x00000000005b7e2c in flush_std_files () at Python/pylifecycle.c:511
#26 0x00000000005be2c7 in Py_FinalizeEx () at Python/pylifecycle.c:580
#27 0x00000000005cb922 in Py_Main () at Modules/main.c:830
#28 0x0000000000483dbc in main (argc=6, argv=0x7ffd8b54f9f8) at ./Programs/python.c:69