[PyQt] PyQt/SIP with no tp_mro

[Paul Bonser]

I'll see if I can come up with a minimal test to reproduce it. Right now
it's happening in the context of a fairly large system.

On Sun, Jul 10, 2011 at 12:25 PM, Phil Thompson <phil at riverbankcomputing.com
> wrote:

> On Thu, 7 Jul 2011 14:27:25 -0500, Paul Bonser <misterpib at gmail.com>
> wrote:
> > I'm running into an issue with SIP/PyQt where sip_api_is_py_method is
> > getting called and it is segfaulting when it gets to this section:
> >
> >>     cls = (PyObject *)Py_TYPE(sipSelf);
> >>     mro = ((PyTypeObject *)cls)->tp_mro;
> >>     assert(PyTuple_Check(mro));
> >
> > Because mro ends up being NULL.
> >
> > This is the backtrace:
> >
> > #0  0x00007f880d00d8ef in sip_api_is_py_method (gil=0x7fff6a7b6d6c,
> > pymc=0x587e7e9 "", sipSelf=0x4e21b90, cname=0x0, mname=0x7f880c81cf92
> > "eventFilter") at siplib.c:7586
> > #1  0x00007f880c7e3cb0 in sipQObject::eventFilter (this=0x587e7d0,
> > a0=0x57e6660, a1=0x5cde260) at sipQtCoreQObject.cpp:360
> > #2  0x00007f880c276627 in
> > QCoreApplicationPrivate::sendThroughObjectEventFilters (this=<value
> > optimized out>, receiver=0x57e6660, event=0x5cde260) at
> > kernel/qcoreapplication.cpp:846
> > #3  0x00007f8809f549b1 in QApplicationPrivate::notify_helper
> > (this=0x19e6820, receiver=0x57e6660, e=0x5cde260) at
> > kernel/qapplication.cpp:4453
> > #4  0x00007f8809f593aa in QApplication::notify (this=0x1f8c960,
> > receiver=0x57e6660, e=0x5cde260) at kernel/qapplication.cpp:3861
> > #5  0x00007f880b146d28 in sipQApplication::notify (this=0x1f8c960,
> > a0=0x57e6660, a1=0x5cde260) at sipQtGuiQApplication.cpp:297
> > #6  0x00007f880c27649c in QCoreApplication::notifyInternal
> > (this=0x1f8c960, receiver=0x57e6660, event=0x5cde260) at
> > kernel/qcoreapplication.cpp:731
> > #7  0x00007f880c279c25 in sendEvent (receiver=0x0, event_type=0,
> > data=0x1f8b4c0) at
> > ../../include/QtCore/../../src/corelib/kernel/qcoreapplication.h:215
> > #8  QCoreApplicationPrivate::sendPostedEvents (receiver=0x0,
> > event_type=0, data=0x1f8b4c0) at kernel/qcoreapplication.cpp:1372
> > #9  0x00007f880c2a1253 in sendPostedEvents (s=0x1fa4560) at
> > ../../include/QtCore/../../src/corelib/kernel/qcoreapplication.h:220
> > #10 postEventSourceDispatch (s=0x1fa4560) at
> > kernel/qeventdispatcher_glib.cpp:277
> > #11 0x00007f880ba61bcd in g_main_context_dispatch () from
> > /lib/x86_64-linux-gnu/libglib-2.0.so.0
> > #12 0x00007f880ba623a8 in ?? () from
> /lib/x86_64-linux-gnu/libglib-2.0.so.0
> > #13 0x00007f880ba62639 in g_main_context_iteration () from
> > /lib/x86_64-linux-gnu/libglib-2.0.so.0
> > #14 0x00007f880c2a13ef in QEventDispatcherGlib::processEvents
> > (this=0x1fa1be0, flags=<value optimized out>) at
> > kernel/qeventdispatcher_glib.cpp:422
> > #15 0x00007f8809ffbdfe in QKeyMapperPrivate::possibleKeysCore
> > (this=0x7f880c279f9f, event=<value optimized out>) at
> > kernel/qkeymapper_x11.cpp:386
> > #16 0x0000000003a16030 in ?? ()
> > #17 0x7fffffff05384200 in ?? ()
> > #18 0x0000002200000013 in ?? ()
> > #19 0x000000000398ec34 in ?? ()
> > #20 0x0000000003979b40 in ?? ()
> > #21 0x000000000398cd40 in ?? ()
> > #22 0x0000000003927f50 in ?? ()
> > #23 0x0000000000000000 in ?? ()
> >
> > Can anyone tell me in what situations tp_mro might end up being NULL?
> > It seems like that should really only be the case during object
> > initialization, right?
> >
> > Adding the following before the assert line seems to alleviate the
> issue:
> >
> >>     if (mro == NULL)
> >>     {
> >> #ifdef WITH_THREAD
> >>         PyGILState_Release(*gil);
> >> #endif
> >>         return NULL;
> >>     }
> >
> > Is this a valid solution, or should the problem be tracked down to the
> > source of tp_mro being NULL?
>
> If the mro is NULL then something is wrong.
>
> Do you have a test that reproduces the problem?
>
> Phil
>



-- 
Paul Bonser | http://probablyprogramming.com | @pib
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://www.riverbankcomputing.com/pipermail/pyqt/attachments/20110710/fb570e54/attachment-0001.html>