New submission from Dmitry Marakasov <amd...@amdmi3.ru>:
System: FreeBSD 12.0-RELEASE, amd64.
This simple program
from multiprocessing import Pool
from time import sleep
Pool().map(sleep, [0.01] * 10)
works fine with python 3.7, but is likely (about 20-50% probability on my 4
core box) to hang with python 3.8. Example backtraces after interruption:
% python3.8 1.py
^CException ignored in: <Finalize object, dead>
Traceback (most recent call last):
File "/usr/local/lib/python3.8/multiprocessing/util.py", line 201, in __call__
Process ForkPoolWorker-2:
Process ForkPoolWorker-4:
res = self._callback(*self._args, **self._kwargs)
File "/usr/local/lib/python3.8/multiprocessing/pool.py", line 689, in
_terminate_pool
cls._help_stuff_finish(inqueue, task_handler, len(pool))
File "/usr/local/lib/python3.8/multiprocessing/pool.py", line 674, in
_help_stuff_finish
inqueue._rlock.acquire()
KeyboardInterrupt:
Process ForkPoolWorker-3:
Process ForkPoolWorker-1:
% python3.8 1.py
^CException ignored in: <Finalize object, dead>
Traceback (most recent call last):
File "/usr/local/lib/python3.8/multiprocessing/util.py", line 201, in __call__
Process ForkPoolWorker-3:
Process ForkPoolWorker-4:
Process ForkPoolWorker-1:
res = self._callback(*self._args, **self._kwargs)
File "/usr/local/lib/python3.8/multiprocessing/pool.py", line 689, in
_terminate_pool
cls._help_stuff_finish(inqueue, task_handler, len(pool))
File "/usr/local/lib/python3.8/multiprocessing/pool.py", line 674, in
_help_stuff_finish
inqueue._rlock.acquire()
KeyboardInterrupt:
Process ForkPoolWorker-2:
% python3.8 1.py
^CException ignored in: <Finalize object, dead>
Process ForkPoolWorker-2:
Process ForkPoolWorker-3:
Traceback (most recent call last):
File "/usr/local/lib/python3.8/multiprocessing/util.py", line 201, in __call__
Process ForkPoolWorker-1:
res = self._callback(*self._args, **self._kwargs)
File "/usr/local/lib/python3.8/multiprocessing/pool.py", line 689, in
_terminate_pool
cls._help_stuff_finish(inqueue, task_handler, len(pool))
File "/usr/local/lib/python3.8/multiprocessing/pool.py", line 674, in
_help_stuff_finish
Traceback (most recent call last):
Traceback (most recent call last):
File "/usr/local/lib/python3.8/multiprocessing/process.py", line 313, in
_bootstrap
self.run()
File "/usr/local/lib/python3.8/multiprocessing/process.py", line 313, in
_bootstrap
self.run()
File "/usr/local/lib/python3.8/multiprocessing/process.py", line 108, in run
self._target(*self._args, **self._kwargs)
File "/usr/local/lib/python3.8/multiprocessing/process.py", line 108, in run
self._target(*self._args, **self._kwargs)
File "/usr/local/lib/python3.8/multiprocessing/pool.py", line 114, in worker
task = get()
File "/usr/local/lib/python3.8/multiprocessing/pool.py", line 114, in worker
task = get()
File "/usr/local/lib/python3.8/multiprocessing/queues.py", line 355, in get
with self._rlock:
File "/usr/local/lib/python3.8/multiprocessing/queues.py", line 355, in get
with self._rlock:
File "/usr/local/lib/python3.8/multiprocessing/synchronize.py", line 95, in
__enter__
return self._semlock.__enter__()
File "/usr/local/lib/python3.8/multiprocessing/synchronize.py", line 95, in
__enter__
return self._semlock.__enter__()
KeyboardInterrupt
KeyboardInterrupt
inqueue._rlock.acquire()
KeyboardInterrupt:
Traceback (most recent call last):
File "/usr/local/lib/python3.8/multiprocessing/process.py", line 313, in
_bootstrap
self.run()
File "/usr/local/lib/python3.8/multiprocessing/process.py", line 108, in run
self._target(*self._args, **self._kwargs)
File "/usr/local/lib/python3.8/multiprocessing/pool.py", line 114, in worker
task = get()
File "/usr/local/lib/python3.8/multiprocessing/queues.py", line 356, in get
res = self._reader.recv_bytes()
File "/usr/local/lib/python3.8/multiprocessing/connection.py", line 216, in
recv_bytes
buf = self._recv_bytes(maxlength)
File "/usr/local/lib/python3.8/multiprocessing/connection.py", line 414, in
_recv_bytes
buf = self._recv(4)
File "/usr/local/lib/python3.8/multiprocessing/connection.py", line 379, in
_recv
chunk = read(handle, remaining)
KeyboardInterrupt
Process ForkPoolWorker-4:
Related issue in FreeBSD bugzilla:
https://bugs.freebsd.org/bugzilla/show_bug.cgi?id=241801
----------
components: Library (Lib)
messages: 356243
nosy: AMDmi3
priority: normal
severity: normal
status: open
title: python 3.8 hang in multiprocessing.Pool() locking on FreeBSD
versions: Python 3.8
_______________________________________
Python tracker <rep...@bugs.python.org>
<https://bugs.python.org/issue38744>
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