[Development] crash when activating timers

[Thiago Macieira]

On Wednesday 13 August 2014 17:07:16 Daniel Teske wrote:
> On Wednesday 13 Aug 2014 08:05:52 Thiago Macieira wrote:
> > On Wednesday 13 August 2014 14:32:13 Ziller Eike wrote:
> > > So my question: Does anyone have any idea how this could possibly
> > > happen,
> > > how we could reproduce and/or debug and fix it?
> > 
> > I also got a bug report that is similar:
> > https://bugreports.qt-project.org/browse/QTBUG-40636
> > 
> > It's right now in "need info" state. There's nothing I can do with what's
> > reported there or by your backtrace. Any chance we can convince people to
> > run Creator inside valgrind?
> > 
> > Also, please store the debug files from the build somewhere.
> 
> There is a valgrind log attached to the creator bug.

Hmm

==10972== Invalid read of size 8                                                                                                  
==10972==    at 0x6528718: QCoreApplication::notifyInternal(QObject*, QEvent*) 
(in /usr/local/Trolltech/5.2.1/gcc_64/lib/libQt5Core.so.5.2.1)
==10972==  Address 0x32c86588 is 8 bytes before a block of size 32 free'd
==10972==    at 0x4C2B60C: free (in /usr/lib/valgrind/vgpreload_memcheck-
amd64-linux.so)
==10972==    by 0x1606157F: CPlusPlus::CreateBindings::~CreateBindings() 
(qalgorithms.h:323)

That doesn't make sense. CPlusPlus::CreateBindings doesn't use any QObject, so 
it shouldn't affect the event processing.

Theories so far:
1) bug in QSharedPointer, corrupting the pointer to be freed
2) bug in QSharedPointer, keeping the pointer past real freeing (dangling 
pointer, so it freed something it shouldn't have)
3) bug in valgrind, reporting bad info
4) bug in malloc
5) thread-safety problem


-- 
Thiago Macieira - thiago.macieira (AT) intel.com
  Software Architect - Intel Open Source Technology Center