QImage crash when saving image(Qt5.0.2) on mac osx 10.8.3

[stereomatching]

Codes

@#include <functional>

#include <QApplication>
#include <QtConcurrent/QtConcurrentMap>
#include <QImage>
#include <QLabel>

//QMutex mutex;

int process_image_impl(QString const &name)
{
QImage image(name);

if(!image.isNull()){                
     //QMutexLocker(&QMutex);  you have to lock it to prevent undefined behavior
     image.save("save/" + name);       
}

return 0;

}

int main(int argc, char *argv[])
{
QApplication a(argc, argv);

namespace ph = std::placeholders;

QStringList image_name;
for(size_t i = 0; i != 10; ++i){
    image_name <<("onebit_" + QString::number(30 + i) + ".png");
}
QtConcurrent::blockingMapped(image_name, std::bind<int>(process_image_impl, ph::_1));

QLabel w;
w.show();

return a.exec(&#41;;

}@

Sometimes this would crash(race condition?) if you don't lock the save function
Is this a bug? Or a behavior of save?In Qt4 I haven't found this kind of problem yet

Sorry, I don't know how to trace the bugs by callstack on mac yet
It wouldn't generate the callstack trace like this page show

"callstack":http://doc.qt.digia.com/qtcreator/creator-debug-mode.html

These are part of the error messages after the .app crash
Anyone know how to decipher the messages?
Could I find out the program crash on which line by the messages?
Or I have an easier way to map the address to source codes?

"error messages":http://www.flickr.com/photos/92283971@N04/8678167798/in/photostream

Should I treat this as a bug and report?

ps : there are the other small bug, the SLOT aboutQt will always show you you are using Qt5.0.1 but not Qt5.0.2