Red Hat Bugzilla – Bug 800085
Memory leaks found in py-radix-0.5-9.fc17 using gcc-with-cpychecker static analyzer
Last modified: 2015-02-17 09:08:54 EST
Description of problem:
I've been writing an experimental static analysis tool to detect bugs commonly occurring within C Python extension modules:
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):
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:
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):
gcc-python-plugin post-0.9 git 11462291a66c8db693c8884cb84b795bb5988ffb running the checker in an *f16* chroot
Reported upstream http://code.google.com/p/py-radix/issues/detail?id=5
This bug appears to have been reported against 'rawhide' during the Fedora 19 development cycle.
Changing version to '19'.
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cycle bugs. We are very sorry. It will help us with cleanup during Fedora 19 End Of Life. Thank you.)
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