Bug 800085 - Memory leaks found in py-radix-0.5-9.fc17 using gcc-with-cpychecker static analyzer
Summary: Memory leaks found in py-radix-0.5-9.fc17 using gcc-with-cpychecker static an...
Keywords:
Status: CLOSED EOL
Alias: None
Product: Fedora
Classification: Fedora
Component: py-radix
Version: 19
Hardware: Unspecified
OS: Unspecified
unspecified
unspecified
Target Milestone: ---
Assignee: Matt Domsch
QA Contact: Fedora Extras Quality Assurance
URL: http://fedorapeople.org/~dmalcolm/gcc...
Whiteboard:
Depends On:
Blocks: cpychecker
TreeView+ depends on / blocked
 
Reported: 2012-03-05 17:40 UTC by Dave Malcolm
Modified: 2015-02-17 14:08 UTC (History)
1 user (show)

Fixed In Version:
Doc Type: Bug Fix
Doc Text:
Clone Of:
Environment:
Last Closed: 2015-02-17 14:08:54 UTC
Type: ---
Embargoed:


Attachments (Terms of Use)

Description Dave Malcolm 2012-03-05 17:40:36 UTC
Description of problem:
I've been writing an experimental static analysis tool to detect bugs commonly occurring within C Python extension modules:
  https://fedorahosted.org/gcc-python-plugin/
  http://gcc-python-plugin.readthedocs.org/en/latest/cpychecker.html
  http://fedoraproject.org/wiki/Features/StaticAnalysisOfPythonRefcounts

I ran the latest version of the tool (in git master; post 0.9) on
py-radix-0.5-9.fc17.src.rpm, and it reports various errors.

You can see a list of errors here, triaged into categories (from most significant to least significant):
http://fedorapeople.org/~dmalcolm/gcc-python-plugin/2012-03-05/py-radix-0.5-9.fc17/

I've manually reviewed the issues reported by the tool.

Within the category "Reference leaks" the 2 issues reported appear to reflect genuine memory leaks within the code:
PyList_Append adds a new reference to the item passed it, it doesn't steal a reference, hence:
   PyList_Append(list, Py_BuildValue())
will leak a reference to the built value.

Also, Py_BuildValue("O") adds a new reference for the result to the input object, rather than stealing one.  The subsequent Py_INCREF on the inputs is thus erroneous.  (also Py_BuildValue("(OO)" could fail if the 2-tuple can't be allocated when under low memory conditions).

Within the category "Reference count too low within an initialization routine" the 1 issue reported is inconsequential.

Within the category "Possible reference leaks" the 1 issue reported may or may not be a bug, depending on whether radix_getstate() returns a borrowed reference or a new one.  The Py_INCREF following a Py_BuildValue("O") looks incorrect also.

Within the category "Returning (PyObject*)NULL without setting an exception" the 3 issues reported may well be false positives: the checker doesn't know whether or now args_to_prefix sets an exception when it returns NULL.

There may of course be other bugs in my checker tool.

Hope this is helpful; let me know if you need help reading the logs that the tool generates - I know that it could use some improvement.

Version-Release number of selected component (if applicable):
py-radix-0.5-9.fc17
gcc-python-plugin post-0.9 git 11462291a66c8db693c8884cb84b795bb5988ffb running the checker in an *f16* chroot

Comment 1 Matt Domsch 2012-03-06 05:18:50 UTC
Reported upstream http://code.google.com/p/py-radix/issues/detail?id=5

Comment 2 Fedora End Of Life 2013-04-03 16:05:11 UTC
This bug appears to have been reported against 'rawhide' during the Fedora 19 development cycle.
Changing version to '19'.

(As we did not run this process for some time, it could affect also pre-Fedora 19 development
cycle bugs. We are very sorry. It will help us with cleanup during Fedora 19 End Of Life. Thank you.)

More information and reason for this action is here:
https://fedoraproject.org/wiki/BugZappers/HouseKeeping/Fedora19

Comment 3 Fedora End Of Life 2015-01-09 17:02:48 UTC
This message is a notice that Fedora 19 is now at end of life. Fedora 
has stopped maintaining and issuing updates for Fedora 19. It is 
Fedora's policy to close all bug reports from releases that are no 
longer maintained. Approximately 4 (four) weeks from now this bug will
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Comment 4 Fedora End Of Life 2015-02-17 14:08:54 UTC
Fedora 19 changed to end-of-life (EOL) status on 2015-01-06. Fedora 19 is
no longer maintained, which means that it will not receive any further
security or bug fix updates. As a result we are closing this bug.

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