167d1f48-81c8-4cdf-91c6-26d7097f932f
commented
5 years ago Hi!
I found a bug in the multiprocessing module.
The documentation (https://docs.python.org/3.6/library/multiprocessing.html) for the Queue.get method says: "If timeout is a positive number, it blocks at most timeout seconds ..."
But the Queue.get method freezes if the process filling the queue terminates while reading data.
In the attachment is an example of a program (testqueue.py) that freezes after ~ 5-30 seconds.
After pressing <control>-<c>, the output is as follows:
Traceback (most recent call last):
File "./testqueue.py", line 45, in <module>
result = ps_queues[cpu].get(timeout=2)
File "/usr/lib64/python3.6/multiprocessing/queues.py", line 108, in get
res = self._recv_bytes()
File "/usr/lib64/python3.6/multiprocessing/connection.py", line 216, in recv_bytes
buf = self._recv_bytes(maxlength)
File "/usr/lib64/python3.6/multiprocessing/connection.py", line 411, in _recv_bytes
return self._recv(size)
File "/usr/lib64/python3.6/multiprocessing/connection.py", line 379, in _recv
chunk = read(handle, remaining)
KeyboardInterruptPlease fix it.
iritkatriel
eshkrig
Note: these values reflect the state of the issue at the time it was migrated and might not reflect the current state.
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GitHub fields: ```python assignee = None closed_at = None created_at =
labels = ['extension-modules', 'type-bug', '3.9']
title = 'A bug in the multiprocessing module'
updated_at =
user = 'https://bugs.python.org/eshkrig'
```
bugs.python.org fields:
```python
activity =
actor = 'eshkrig'
assignee = 'none'
closed = False
closed_date = None
closer = None
components = ['Extension Modules']
creation =
creator = 'eshkrig'
dependencies = []
files = ['48609']
hgrepos = []
issue_num = 38195
keywords = []
message_count = 3.0
messages = ['352613', '411500', '411645']
nosy_count = 4.0
nosy_names = ['pitrou', 'davin', 'eshkrig', 'iritkatriel']
pr_nums = []
priority = 'normal'
resolution = None
stage = 'resolved'
status = 'open'
superseder = None
type = 'behavior'
url = 'https://bugs.python.org/issue38195'
versions = ['Python 3.9']
```