Bugs item #1199282, was opened at 2005-05-10 20:24
Message generated for change (Comment added) made by astrand
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Category: Python Library
Group: Python 2.4
Status: Open
Resolution: None
Priority: 5
Submitted By: cheops (atila-cheops)
Assigned to: Peter Ã
strand (astrand)
Summary: subprocess _active.remove(self) self not in list _active
Initial Comment:
I start a subprocess in a seperate thread (25 concurrent
threads)
in some of the threads the following error occurs
Exception in thread Thread-4:
Traceback (most recent call last):
File "C:\Python24\lib\threading.py", line 442, in
__bootstrap
self.run()
File "upgrade.py", line 45, in run
returncode = p.wait()
File "C:\Python24\lib\subprocess.py", line 765, in wait
_active.remove(self)
ValueError: list.remove(x): x not in list
this is the code that starts the subprocess and where I
wait for the result
p = subprocess.Popen('command', \
stdin=None,
stdout=subprocess.PIPE, \
stderr=subprocess.STDOUT,
universal_newlines=True)
returncode = p.wait()
errormessage = p.stdout.readlines()
----------------------------------------------------------------------
>Comment By: Peter Ã
strand (astrand)
Date: 2006-03-29 07:11
Message:
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>I think accesses to _active should be serialized in a
>thread-safe way. _active could be a Queue (from the Queue
>module) for example
Simply list operations such as remove() and append() are
thread safe, so there should be no need for a Queue. Also, a
Queue cannot be used since the subprocess module needs to be
compatible with Python 2.2.
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Comment By: Tristan Faujour (tfaujour)
Date: 2006-03-29 01:17
Message:
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I am running into the same problem on a Windows 2k/XP
plateform with a multi-threaded application. It occurs randomly.
It has never appened (yet) on a Linux plateform.
I think accesses to _active should be serialized in a
thread-safe way. _active could be a Queue (from the Queue
module) for example.
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Comment By: HVB bei TUP (hvb_tup)
Date: 2006-01-25 09:10
Message:
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Wouldn't it be best to completely remove any references
to "_active" and "_cleanup"?
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Comment By: cheops (atila-cheops)
Date: 2006-01-25 08:08
Message:
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As suggested by astrand
adding a try ... except clause in the file subprocess.py did
the job
I had to add that try ... except clause in 2 places
if you look in the file there are 2 instances were
list.remove(x) occurs unprotected.
try:
list.remove(x)
except:
pass
I have worked with 2.4.0, 2.4.1 and 2.4.2 and all three
needed the patch.
Hope this helps.
----------------------------------------------------------------------
Comment By: HVB bei TUP (hvb_tup)
Date: 2006-01-23 17:34
Message:
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BTW: In my case, I call python.exe from a Windows service.
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Comment By: HVB bei TUP (hvb_tup)
Date: 2006-01-23 17:30
Message:
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I have a similar problem.
Python 2.4.1 under MS Windows 2003,
Multi-Threaded application (about concurrent 10 threads).
In my case the same error occurs during _cleanup called
from __init__ :
File "E:\lisa_ins\ewu\coop\reporting\python\tup_lisa\util\t
hreadutil.py", line 582, in callSubProcess
creationflags = creationflags
File "C:\Python24\lib\subprocess.py", line 506, in
__init__
_cleanup()
File "C:\Python24\lib\subprocess.py", line 414, in
_cleanup
inst.poll()
File "C:\Python24\lib\subprocess.py", line 755, in poll
_active.remove(self)
ValueError: list.remove(x): x not in list
Is there a work-around?
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Comment By: cheops (atila-cheops)
Date: 2005-09-19 11:29
Message:
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I noticed this bug under windows
to reproduce the bug, I attached the script I use, but this
needs input, I tried with a simpler example (pinging a number
of host concurrently) but that did not cause the bug.
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Comment By: Peter Ã
strand (astrand)
Date: 2005-06-23 18:03
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I believe it should be sufficient to add a try...except
clause around _active.remove(). Can you upload a complete
example that triggers the bug? Have you noticed this bug on
Windows, UNIX or both platforms?
----------------------------------------------------------------------
Comment By: cheops (atila-cheops)
Date: 2005-05-12 12:17
Message:
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this might be related to bug 1183780
----------------------------------------------------------------------
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