I'm confused with this crash problem

In my application, I called a Google library 's login function, it's in anotherthread, and after I get the response of login, the application seems freeze. I use gdb to get the following stack info , some body please help me know what's the meaning of it, how does it happen
Code:
#0 0x414d34d4 in QMetaObject::cast(QObject*) const () 
from /opt/Qt/lib/libQtCore.so.4 
#1 0x40891298 in QWidgetPrivate::paintBackground(QPainter*, QRegion const&, int) const () from /opt/Qt/lib/libQtGui.so.4 
#2 0x4089c4bc in QWidgetPrivate::drawWidget(QPaintDevice*, QRegion const&, QPoint const&, int, QPainter*, QWidgetBackingStore*) () 
from /opt/Qt/lib/libQtGui.so.4 
#3 0x4089cd40 in QWidgetPrivate::paintSiblingsRecursive(QPaintDevice*, QList<QObject*> const&, int, QRegion const&, QPoint const&, int, QPainter*, QWidgetBackingStore*) () from /opt/Qt/lib/libQtGui.so.4 
#4 0x4089cbe4 in QWidgetPrivate::paintSiblingsRecursive(QPaintDevice*, QList<QObject*> const&, int, QRegion const&, QPoint const&, int, QPainter*, QWidgetBackingStore*) () from /opt/Qt/lib/libQtGui.so.4 
#5 0x4089cbe4 in QWidgetPrivate::paintSiblingsRecursive(QPaintDevice*, QList<QObject*> const&, int, QRegion const&, QPoint const&, int, QPainter*, QWidgetBackingStore*) () from /opt/Qt/lib/libQtGui.so.4 
#6 0x4089cbe4 in QWidgetPrivate::paintSiblingsRecursive(QPaintDevice*, QList<QObject*> const&, int, QRegion const&, QPoint const&, int, QPainter*, QWidgetBackingStore*) () from /opt/Qt/lib/libQtGui.so.4 
#7 0x4089cbe4 in QWidgetPrivate::paintSiblingsRecursive(QPaintDevice*, QList<QObject*> const&, int, QRegion const&, QPoint const&, int, QPainter*, QWidgetBackingStore*) () from /opt/Qt/lib/libQtGui.so.4 
#8 0x4089cbe4 in QWidgetPrivate::paintSiblingsRecursive(QPaintDevice*, QList<QObject*> const&, int, QRegion const&, QPoint const&, int, QPainter*, QWidgetBackingStore*) () from /opt/Qt/lib/libQtGui.so.4 
#9 0x4089cbe4 in QWidgetPrivate::paintSiblingsRecursive(QPaintDevice*, QList<QObject*> const&, int, QRegion const&, QPoint const&, int, QPainter*, QWidgetBackingStore*) () from /opt/Qt/lib/libQtGui.so.4 
#10 0x4089cbe4 in QWidgetPrivate::paintSiblingsRecursive(QPaintDevice*, QList<QObject*> const&, int, QRegion const&, QPoint const&, int, QPainter*, QWidgetBackingStore*) () from /opt/Qt/lib/libQtGui.so.4 
#11 0x4089cbe4 in QWidgetPrivate::paintSiblingsRecursive(QPaintDevice*, QList<QObject*> const&, int, QRegion const&, QPoint const&, int, QPainter*, QWidgetBackingStore*) () from /opt/Qt/lib/libQtGui.so.4 
#12 0x4089cbe4 in QWidgetPrivate::paintSiblingsRecursive(QPaintDevice*, QList<QObject*> const&, int, QRegion const&, QPoint const&, int, QPainter*, QWidgetBackingStore*) () from /opt/Qt/lib/libQtGui.so.4 
#13 0x4089cbe4 in QWidgetPrivate::paintSiblingsRecursive(QPaintDevice*, QList<QObject*> const&, int, QRegion const&, QPoint const&, int, QPainter*, QWidgetBackingStore*) () from /opt/Qt/lib/libQtGui.so.4 
#14 0x4089c1f4 in QWidgetPrivate::drawWidget(QPaintDevice*, QRegion const&, QPoint const&, int, QPainter*, QWidgetBackingStore*) () 
from /opt/Qt/lib/libQtGui.so.4 
#15 0x40a9e040 in QWidgetBackingStore::sync() () 
from /opt/Qt/lib/libQtGui.so.4 
#16 0x4088ccd4 in QWidgetPrivate::syncBackingStore() () 
from /opt/Qt/lib/libQtGui.so.4 
#17 0x4089de10 in QWidget::event(QEvent*) () from /opt/Qt/lib/libQtGui.so.4 
#18 0x40d0c270 in QFrame::event(QEvent*) () from /opt/Qt/lib/libQtGui.so.4 
#19 0x40d7aa04 in QStackedWidget::event(QEvent*) () 
from /opt/Qt/lib/libQtGui.so.4 
#20 0x40839d70 in QApplicationPrivate::notify_helper(QObject*, QEvent*) () 
from /opt/Qt/lib/libQtGui.so.4 
#21 0x4083f438 in QApplication::notify(QObject*, QEvent*) () 
from /opt/Qt/lib/libQtGui.so.4 
#22 0x414cbd00 in QCoreApplication::notifyInternal(QObject*, QEvent*) () 
from /opt/Qt/lib/libQtCore.so.4 
#23 0x414cd070 in QCoreApplicationPrivate::sendPostedEvents(QObject*, int, QThreadData*) () from /opt/Qt/lib/libQtCore.so.4 
#24 0x00000000 in ?? ()