[Numpy-discussion] segfault caused by incorrect Py_DECREF in ufunc

Travis Oliphant oliphant@ee.byu....
Fri Jul 6 14:43:22 CDT 2007


Tom Denniston wrote:

>Below is the code around line 900 for ufuncobject.c
>(http://svn.scipy.org/svn/numpy/trunk/numpy/core/src/ufuncobject.c)
>
>There is a decref labeled with ">>>" below that is incorrect.  As per
>the python documentation
>(http://docs.python.org/api/dictObjects.html):
>
>#PyObject* PyDict_GetItem( PyObject *p, PyObject *key)
>#
>#Return value: Borrowed reference.
>#Return the object from dictionary p which has a key key. Return NULL
>if the key #key is not present, but without setting an exception.
>
>PyDict_GetItem returns a borrowed reference.  Therefore this code does
>not own the contents to which the obj pointer points and should not
>decref on it.  Simply removing the Py_DECREF(obj) line gets rid of the
>segfault.
>
>I was wondering if someone could confirm that my interpretation is
>correct and remove the line.  I don't have access to the svn or know
>how to change it.
>
>Most people do not see this problem because it only affects user defined types.
>  
>

You are right on with your analysis.  Thank you for the test, check, and 
fix.

I've changed it in SVN. 

Best regards,

-Travis



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