[issue16447] SEGFAULT when setting type.__name__

[STINNER Victor]

STINNER Victor added the comment:

It looks like the bug is the pattern "Py_DECREF(obj->attr); obj->attr = new_value;". Replacing it with "{ PyObject *tmp = obj->attr; obj->attr = new_value; Py_DECREF(tmp); }" does fix this specific issue.

We can use the coccinelle tool to replace all such patterns in the whole CPython code base using attached py_decref_replace.spatch "semantic patch". See also issue #16445, I proposed a similar idea (and another semantic patch).

Attached python27_decref_replace.patch patch is the result of the command "spatch -in_place -sp_file py_decref_replace.spatch -dir .".

The patch is quite huge, I didn't read it yet :-)


 Mac/Modules/carbonevt/_CarbonEvtmodule.c |   7 +++++--
 Mac/Modules/list/_Listmodule.c           |   7 +++++--
 Modules/_bsddb.c                         |  42 ++++++++++++++++++++++++++++++------------
 Modules/_csv.c                           |   7 +++++--
 Modules/_ctypes/_ctypes.c                |  98 ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++----------------------------
 Modules/_curses_panel.c                  |   7 +++++--
 Modules/_elementtree.c                   |  81 ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++---------------------
 Modules/_json.c                          |   7 +++++--
 Modules/_sqlite/connection.c             |  28 ++++++++++++++++++++--------
 Modules/_sqlite/cursor.c                 |  42 ++++++++++++++++++++++++++++++------------
 Modules/bz2module.c                      |   9 +++++----
 Modules/cPickle.c                        |  36 +++++++++++++++++++++++++++---------
 Modules/flmodule.c                       |  28 ++++++++++++++++++++--------
 Modules/itertoolsmodule.c                |   7 +++++--
 Modules/selectmodule.c                   |   7 +++++--
 Modules/signalmodule.c                   |   7 +++++--
 Modules/svmodule.c                       |   7 +++++--
 Modules/zlibmodule.c                     |  23 +++++++++++++++--------
 Objects/descrobject.c                    |   7 +++++--
 Objects/exceptions.c                     |  21 +++++++++++++++------
 Objects/fileobject.c                     |  14 ++++++++++----
 Objects/funcobject.c                     |   7 +++++--
 Objects/typeobject.c                     |  21 +++++++++++++++------
 Python/ceval.c                           |   7 +++++--
 Python/sysmodule.c                       |   7 +++++--
 25 files changed, 382 insertions(+), 152 deletions(-)

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nosy: +haypo
Added file: http://bugs.python.org/file27931/py_decref_replace.spatch

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Python tracker <report at bugs.python.org>
<http://bugs.python.org/issue16447>
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