(gdb) bt
#0  WSEGL_SwapDrawable (hDrawable=0x0, ui32Data=1, i32NumRects=0, pi32Rects=0x0) at dri2_ws.c:990
#1  0x3c1e2f00 in IMGeglSwapBuffersRegion (eglDpy=<value optimized out>, draw=0x2295a8, numRects=0, rects=0x0)
    at khronos_egl.c:6362
#2  0x3b468abc in QEglContext::swapBuffers (this=<value optimized out>, surface=0x2295a8) at egl/qegl.cpp:524
#3  0x3ac07fa4 in QGLWindowSurface::flush (this=0x43507040, widget=<value optimized out>, rgn=<value optimized out>, 
    offset=...) at qwindowsurface_gl.cpp:663
#4  0x3afa7464 in QRuntimeWindowSurface::flush (this=0x4350e3c0, widget=0x1, region=..., offset=<value optimized out>)
    at painting/qgraphicssystem_runtime.cpp:274
#5  0x3afc5e88 in qt_flush (this=0x43501df8, widget=<value optimized out>, surface=<value optimized out>)
    at painting/qbackingstore.cpp:104
#6  QWidgetBackingStore::flush (this=0x43501df8, widget=<value optimized out>, surface=<value optimized out>)
    at painting/qbackingstore.cpp:1399
#7  0x3afc758c in QWidgetBackingStore::sync (this=<value optimized out>) at painting/qbackingstore.cpp:1341
#8  0x3adceb28 in QWidgetPrivate::syncBackingStore (this=0x11b7a8) at kernel/qwidget.cpp:1866
#9  0x3adfd2a4 in QETWidget::translateConfigEvent (this=0x11b5c8, event=<value optimized out>)
    at kernel/qapplication_x11.cpp:6222
#10 0x3ae08368 in QApplication::x11ProcessEvent (this=<value optimized out>, event=0xaec6e8b8)
    at kernel/qapplication_x11.cpp:4059
#11 0x3ae337a0 in x11EventSourceDispatch (s=0x1d8e8, callback=<value optimized out>, user_data=<value optimized out>)
    at kernel/qguieventdispatcher_glib.cpp:146
#12 0x3c02c55c in g_main_dispatch (context=<value optimized out>)
    at /home/bifh7/cs2009q3-armel/work/glib2.0-2.28.4/./glib/gmain.c:2440
#13 g_main_context_dispatch (context=<value optimized out>)
    at /home/bifh7/cs2009q3-armel/work/glib2.0-2.28.4/./glib/gmain.c:3013
#14 0x3c030d5c in g_main_context_iterate (context=0x1cae8, block=<value optimized out>, dispatch=<value optimized out>, 
    self=<value optimized out>) at /home/bifh7/cs2009q3-armel/work/glib2.0-2.28.4/./glib/gmain.c:3091
#15 0x3c030fbc in g_main_context_iteration (context=0x1cae8, may_block=1)
    at /home/bifh7/cs2009q3-armel/work/glib2.0-2.28.4/./glib/gmain.c:3154
#16 0x3b8f6a90 in QEventDispatcherGlib::processEvents (this=0x1b0d0, flags=...) at kernel/qeventdispatcher_glib.cpp:422
#17 0x3ae330cc in QGuiEventDispatcherGlib::processEvents (this=0x0, flags=<value optimized out>)
    at kernel/qguieventdispatcher_glib.cpp:204
#18 0x3b8c2b04 in QEventLoop::processEvents (this=<value optimized out>, flags=...) at kernel/qeventloop.cpp:149
#19 0x3b8c2fa8 in QEventLoop::exec (this=0xaec6ea9c, flags=...) at kernel/qeventloop.cpp:201
#20 0x3b8c882c in QCoreApplication::exec () at kernel/qcoreapplication.cpp:1064
#21 0x0000e2f4 in ?? ()