Crash and error message from Python VM

[pcdinh]

BPO	11148
Nosy	@ronaldoussoren, @ned-deily

^{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:

assignee = 'https://github.com/ronaldoussoren'
closed_at = <Date 2011-03-14.17:32:10.286>
created_at = <Date 2011-02-08.10:19:28.592>
labels = ['OS-mac', 'interpreter-core', 'type-crash']
title = 'Crash and error message from Python VM'
updated_at = <Date 2011-03-14.17:32:10.284>
user = 'https://bugs.python.org/pcdinh'

bugs.python.org fields:

activity = <Date 2011-03-14.17:32:10.284>
actor = 'ronaldoussoren'
assignee = 'ronaldoussoren'
closed = True
closed_date = <Date 2011-03-14.17:32:10.286>
closer = 'ronaldoussoren'
components = ['Interpreter Core', 'macOS']
creation = <Date 2011-02-08.10:19:28.592>
creator = 'pcdinh'
dependencies = []
files = []
hgrepos = []
issue_num = 11148
keywords = []
message_count = 5.0
messages = ['128168', '128177', '128264', '128280', '130863']
nosy_count = 4.0
nosy_names = ['ronaldoussoren', 'ned.deily', 'neologix', 'pcdinh']
pr_nums = []
priority = 'normal'
resolution = 'duplicate'
stage = 'resolved'
status = 'closed'
superseder = None
type = 'crash'
url = 'https://bugs.python.org/issue11148'
versions = ['Python 2.6']

[pcdinh]

Quite often, I got the following message printed out the console while I run my Python script

pthread_cond_signal: Undefined error: 0

Or it crashed

https://gist.github.com/799841

Tested with Python 2.6.1 and 2.6.6 (Mac)

What I am trying to do is to set up a logging component that collects all messages sent from child processes to a pipe created by the parent process. The logging component is controlled by a thread created by parent process

[ronaldoussoren]

Can you provide a script that shows the problem? Without such a script it will be hard to reproduce, and fix, this problem.

[pcdinh]

I just simplified my script into a smaller one that can be easier to understand and find out what happens

https://gist.github.com/819979

Thanks

[neologix]

I think this issue is related to http://bugs.python.org/issue11158, which is in turn related to http://bugs.python.org/issue6721 (Locks in python standard library should be sanitized on fork).

When a mutex created by a parent process is used from within a child process, this can lead not only to a deadlock, but also to SIGSEGV.

To understand the purpose of pthread_atfork, recall that fork duplicates the whole memory space, including mutexes in their current locking state, but only the calling thread: other threads are not running in the child process. The mutexes are not usable after the fork and must be initialized with pthread_mutex_init in the child process. This is a limitation of the current implementation and might or might not be present in future versions.

They must be initialized.

Suggesting to close both bpo-11148 and bpo-11158 as dupe of bpo-6721.

[ronaldoussoren]

I agree this is a duplicate of bpo-6721. I'm therefore closing this issue.