[Bug python/13316] New: (cpychecker) Suspected memory leak in gdb/python/py-param.c: compute_enum_values

[Bug python/13316] New: (cpychecker) Suspected memory leak in gdb/python/py-param.c: compute_enum_values

[dmalcolm at redhat dot com]

http://sourceware.org/bugzilla/show_bug.cgi?id=13316

             Bug #: 13316
           Summary: (cpychecker) Suspected memory leak in
                    gdb/python/py-param.c: compute_enum_values
           Product: gdb
           Version: HEAD
            Status: NEW
          Severity: normal
          Priority: P2
         Component: python
        AssignedTo: unassigned@sourceware.org
        ReportedBy: dmalcolm@redhat.com
    Classification: Unclassified


Created attachment 6018
  --> http://sourceware.org/bugzilla/attachment.cgi?id=6018
HTML report showing the execution paths that leak memory

See the attached HTML report from gcc-python-plugin's cpychecker.

It looks like a reference count on "*item" is leaked for each time through the
loop in compute_enum_values().

Reading 
  http://docs.python.org/c-api/sequence.html#PySequence_GetItem

a successful call to PySequence_GetItem() is meant to give the caller ownership
of a reference count on the returned PyObject*

Double-checking with Python's Objects/abstract.c:
  PyObject *
  PySequence_GetItem(PyObject *s, Py_ssize_t i)
  {
        [... setup and error handling ...]
        return m->sq_item(s, i);
  }

and looking at e.g. Objects/listobject.c: list_item (the sq_item callback for
PyList_Type): it Py_INCREFs the returned item.

Hence I believe that cpychecker is correctly reporting a memory leak here (for
both the case of a successful execution of compute_enum_values(), and the
failure path it shows).

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[Bug python/13316] (cpychecker) Suspected memory leak in gdb/python/py-param.c: compute_enum_values

[pmuldoon at redhat dot com]

http://sourceware.org/bugzilla/show_bug.cgi?id=13316

Phil Muldoon <pmuldoon at redhat dot com> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
                 CC|                            |pmuldoon at redhat dot com
         AssignedTo|unassigned at sourceware    |pmuldoon at redhat dot com
                   |dot org                     |

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[Bug python/13316] (cpychecker) Suspected memory leak in gdb/python/py-param.c: compute_enum_values

[tromey at redhat dot com]

https://sourceware.org/bugzilla/show_bug.cgi?id=13316

Tom Tromey <tromey at redhat dot com> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
             Status|NEW                         |RESOLVED
                 CC|                            |tromey at redhat dot com
         Resolution|---                         |FIXED
   Target Milestone|---                         |7.7

--- Comment #1 from Tom Tromey <tromey at redhat dot com> ---
I fixed this a while back without realizing there was a PR:

2013-05-20  Tom Tromey  <tromey@redhat.com>

    * python/py-param.c (compute_enum_values): Decref 'item'.

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