[ python-Bugs-1256669 ] Significant memory leak with PyImport_ReloadModule

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Bugs item #1256669, was opened at 2005-08-11 05:49
Message generated for change (Comment added) made by nnorwitz
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Category: None
Group: Python 2.4
Status: Open
Resolution: None
Priority: 5
Submitted By: Ben Held (bheld)
Assigned to: Nobody/Anonymous (nobody)
Summary: Significant memory leak with PyImport_ReloadModule

Initial Comment:
Having recently upgraded to Python 2.4, I am having a 
large memory 
leak with the following code built with VC++ 6.0: 


                PyObject *pName, *pModule; 


                Py_Initialize(); 
                pName = PyString_FromString(argv[1]); 


                pModule = PyImport_Import(pName); 
                Py_DECREF(pName); 


                PyObject* pModule2 = 
PyImport_ReloadModule(pModule)­; 
                Py_DECREF(pModule2); 
                Py_DECREF(pModule); 
                Py_Finalize(); 
                return 0; 


I get leaks of over 500 kb.  I have another program which 
is much more 
complex, in which every call to PyImport_ReloadModule 
is leaking 200+ 
kb, even though I am calling Py_DECREF correctly.


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>Comment By: Neal Norwitz (nnorwitz)
Date: 2005-09-19 23:02

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I just tested with Python 2.4.2 on Linux with valgrind.  It
doesn't report any leaks.  So this could be specific to
Python 2.3.5, Windows, VC++ 6.0 or some other variation.  

Can you provide more info?  For example, what module are you
passing on the command line?  Can you provide that code? 
What objects specifically do you think are leaking?  Where
were they allocated?

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Comment By: Ben Held (bheld)
Date: 2005-09-14 11:09

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This behavior is evident with Python 2.3.5 built on Windows 
with VC++ 6.0.

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Comment By: Collin Winter (collinwinter)
Date: 2005-09-14 10:53

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I've been unable to verify this on Linux. I've tested python
versions 2.2.3, 2.3.5 and 2.4.1, all compiled with gcc 3.3.5
on Debian 3.1 under kernel 2.6.8. I used the sample program
provided by Ben, modified with an infinite loop over the
PyImport_ReloadModule/PyDECREF(pModule2) lines, sleeping for
1 second after every 25 iterations. I tested reloading the
modules distutils, os.path, distutils.command.sdist for 300+
iterations each under each python version. No memory leak
was observed.

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Comment By: Ben Held (bheld)
Date: 2005-08-16 06:56

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Boundschecker shows the leak and I have verified this by 
watching the process memory increase via the task manager.

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Comment By: Martin v. Löwis (loewis)
Date: 2005-08-13 06:34

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How do you know there is a memory leak?

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