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Created on2014-05-13 08:49 byidsvandermolen, last changed2022-04-11 14:58 byadmin. This issue is nowclosed.
| Files | ||||
|---|---|---|---|---|
| File name | Uploaded | Description | Edit | |
| socketserver_reap.diff | neologix,2014-06-07 12:05 | review | ||
| Messages (6) | |||
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| msg218414 -(view) | Author: Ids van der Molen (idsvandermolen) | Date: 2014-05-13 08:49 | |
collect_children routine in SocketServer.py contains two possible race conditions. First one is in while loop "while len(self.active_children) >= self.max_children:". If status of child is collected outside of Socket server (for example in signal handler or something), then the variable self.active_children will not match actual child processes and the os.waitpid(0, 0) within the while loop will raise os.error, errno=10 (ECHILD) "No Child Processes". self.active_children should be emptied in this case, otherwise you'll end up with an endless loop comsuming 100% CPU (as happened to us).The second possible race condition is below in the collect_children routine in the "for child in self.active_children" which contains a statement self.active_children.remove(pid) which would modify the iterator. I do not now about python 2.7, but before this would result in "incorrect iteration".Original code: for child in self.active_children: try: pid, status = os.waitpid(child, os.WNOHANG) except os.error: pid = None if not pid: continue try: self.active_children.remove(pid) except ValueError, e: raise ValueError('%s. x=%d and list=%r' % (e.message, pid, self.active_children))Fixed code: to_remove = [] for child in self.active_children: try: pid, status = os.waitpid(child, os.WNOHANG) except os.error: pid = None if not pid: continue to_remove.append(pid) for pid in to_remove: try: self.active_children.remove(pid) except ValueError, e: raise ValueError('%s. x=%d and list=%r' % (e.message, pid, self.active_children)) | |||
| msg219930 -(view) | Author: Charles-François Natali (neologix)* | Date: 2014-06-07 12:05 | |
Here's a patch fixing both issues. | |||
| msg221122 -(view) | Author: Roundup Robot (python-dev) | Date: 2014-06-20 21:03 | |
New changesetaa5e3f7a5501 by Charles-François Natali in branch '2.7':Issue#21491: SocketServer: Fix a race condition in child processes reaping.http://hg.python.org/cpython/rev/aa5e3f7a5501 | |||
| msg221124 -(view) | Author: Roundup Robot (python-dev) | Date: 2014-06-20 21:42 | |
New changeset2a7375bd09f9 by Charles-François Natali in branch '3.4':Issue#21491: socketserver: Fix a race condition in child processes reaping.http://hg.python.org/cpython/rev/2a7375bd09f9 | |||
| msg221126 -(view) | Author: Roundup Robot (python-dev) | Date: 2014-06-20 21:51 | |
New changesetae0b572ced20 by Charles-François Natali in branch 'default':Issue#21491: socketserver: Fix a race condition in child processes reaping.http://hg.python.org/cpython/rev/ae0b572ced20 | |||
| msg221163 -(view) | Author: Charles-François Natali (neologix)* | Date: 2014-06-21 09:10 | |
Committed, thanks! | |||
| History | |||
|---|---|---|---|
| Date | User | Action | Args |
| 2022-04-11 14:58:03 | admin | set | github: 65690 |
| 2014-06-21 09:10:17 | neologix | set | status: open -> closed versions: + Python 3.3, Python 3.4 type: resource usage -> behavior messages: +msg221163 resolution: fixed stage: patch review -> resolved |
| 2014-06-20 21:51:21 | python-dev | set | messages: +msg221126 |
| 2014-06-20 21:42:38 | python-dev | set | messages: +msg221124 |
| 2014-06-20 21:03:53 | python-dev | set | nosy: +python-dev messages: +msg221122 |
| 2014-06-07 12:05:44 | neologix | set | files: +socketserver_reap.diff nosy: +pitrou,vstinner messages: +msg219930 keywords: +patch,needs review stage: patch review |
| 2014-05-13 08:59:10 | pitrou | set | nosy: +neologix |
| 2014-05-13 08:49:14 | idsvandermolen | create | |