Issue 28326: multiprocessing.Process depends on sys.stdout being open (original) (raw)

Created on 2016-10-01 11:45 by Valentin.Lorentz, last changed 2022-04-11 14:58 by admin. This issue is now closed.

Messages (8)
msg277807 - (view)	Author: ProgVal (Valentin.Lorentz)	Date: 2016-10-01 11:45
Hello, The following code: import sys import multiprocessing sys.stdout.close() def foo(): pass p = multiprocessing.Process(target=foo) p.start() Crashes with: Traceback (most recent call last): File "foo.py", line 10, in p.start() File "/usr/lib/python3.5/multiprocessing/process.py", line 105, in start self._popen = self._Popen(self) File "/usr/lib/python3.5/multiprocessing/context.py", line 212, in _Popen return _default_context.get_context().Process._Popen(process_obj) File "/usr/lib/python3.5/multiprocessing/context.py", line 267, in _Popen return Popen(process_obj) File "/usr/lib/python3.5/multiprocessing/popen_fork.py", line 17, in __init__ sys.stdout.flush() ValueError: I/O operation on closed file. This bug has been reported to me on a daemonized program (written prior to PEP 3143).
msg277849 - (view)	Author: Tiago Antao (tiagoantao) *	Date: 2016-10-02 04:38
I made a small patch for this. This is the first time I submit one, so please be careful with this...
msg278271 - (view)	Author: Terry J. Reedy (terry.reedy) *	Date: 2016-10-07 21:37
Patch looks plausible to me. The flush calls definitely need to be guarded.
msg278273 - (view)	Author: Tiago Antao (tiagoantao) *	Date: 2016-10-07 21:51
This is the first patch that I am submitting. More than willing to do any changes deemed necessary...
msg304713 - (view)	Author: Antoine Pitrou (pitrou) *	Date: 2017-10-21 16:57
In , we see that sys.stdout and sys.stderr can sometimes simply be None, so we must check for that too.
msg304737 - (view)	Author: Antoine Pitrou (pitrou) *	Date: 2017-10-22 09:40
New changeset daeefd2e049b74340307481112a39f77de0f4769 by Antoine Pitrou in branch 'master': bpo-28326: Fix multiprocessing.Process when stdout and/or stderr is closed or None. (#4073) https://github.com/python/cpython/commit/daeefd2e049b74340307481112a39f77de0f4769
msg304740 - (view)	Author: Antoine Pitrou (pitrou) *	Date: 2017-10-22 10:27
New changeset 34ef6da8f5fb03b83268bd35b77fb2183c748b70 by Antoine Pitrou in branch '3.6': [3.6] bpo-28326: Fix multiprocessing.Process when stdout and/or stderr is closed or None. (GH-4073). (#4075) https://github.com/python/cpython/commit/34ef6da8f5fb03b83268bd35b77fb2183c748b70
msg304741 - (view)	Author: Antoine Pitrou (pitrou) *	Date: 2017-10-22 10:27
This is now fixed in 3.6 and 3.7. Closing!