Crash into QQuickText::invalidateFontCaches

0x00007ffff79e2ac0 in QQuickText::invalidateFontCaches() () from /opt/qt/5.4/gcc_64/lib/libQt5Quick.so.5
(gdb) bt
#0  0x00007ffff79e2ac0 in QQuickText::invalidateFontCaches() () from /opt/qt/5.4/gcc_64/lib/libQt5Quick.so.5
#1  0x00007ffff799f542 in QQuickWindowPrivate::polishItems() () from /opt/qt/5.4/gcc_64/lib/libQt5Quick.so.5
#2  0x00007ffff7971dc3 in ?? () from /opt/qt/5.4/gcc_64/lib/libQt5Quick.so.5
#3  0x00007ffff79724ad in ?? () from /opt/qt/5.4/gcc_64/lib/libQt5Quick.so.5
#4  0x00007ffff6c228f4 in QApplicationPrivate::notify_helper(QObject*, QEvent*) () from /opt/qt/5.4/gcc_64/lib/libQt5Widgets.so.5
#5  0x00007ffff6c26506 in QApplication::notify(QObject*, QEvent*) () from /opt/qt/5.4/gcc_64/lib/libQt5Widgets.so.5
#6  0x00007ffff58ccc84 in QCoreApplication::notifyInternal(QObject*, QEvent*) () from /opt/qt/5.4/gcc_64/lib/libQt5Core.so.5
#7  0x00007ffff59269c4 in QTimerInfoList::activateTimers() () from /opt/qt/5.4/gcc_64/lib/libQt5Core.so.5
#8  0x00007ffff5926c6d in ?? () from /opt/qt/5.4/gcc_64/lib/libQt5Core.so.5
#9  0x00007ffff120dd13 in g_main_context_dispatch () from /lib/x86_64-linux-gnu/libglib-2.0.so.0
#10 0x00007ffff120e060 in ?? () from /lib/x86_64-linux-gnu/libglib-2.0.so.0
#11 0x00007ffff120e124 in g_main_context_iteration () from /lib/x86_64-linux-gnu/libglib-2.0.so.0
#12 0x00007ffff5927554 in QEventDispatcherGlib::processEvents(QFlags<QEventLoop::ProcessEventsFlag>) () from /opt/qt/5.4/gcc_64/lib/libQt5Core.so.5
#13 0x00007ffff58caeab in QEventLoop::exec(QFlags<QEventLoop::ProcessEventsFlag>) () from /opt/qt/5.4/gcc_64/lib/libQt5Core.so.5
#14 0x00007ffff58cfdc5 in QCoreApplication::exec() () from /opt/qt/5.4/gcc_64/lib/libQt5Core.so.5
#15 0x000000000041eb45 in main ()