Crash in QWidgetBackingStore when resizing videographicsitem example

The crash below happens reproducibly on Linux. Start the videographicsitem example, choose a video, press play and then resize the window.

laknoll@rincewind-virtual:~/dev/qt5/qtmultimedia/examples/videographicsitem$ gdb ./videographicsitem
GNU gdb (Ubuntu/Linaro 7.4-2012.04-0ubuntu2) 7.4-2012.04
Copyright (C) 2012 Free Software Foundation, Inc.
License GPLv3+: GNU GPL version 3 or later <http://gnu.org/licenses/gpl.html>
This is free software: you are free to change and redistribute it.
There is NO WARRANTY, to the extent permitted by law. Type "show copying"
and "show warranty" for details.
This GDB was configured as "i686-linux-gnu".
For bug reporting instructions, please see:
<http://bugs.launchpad.net/gdb-linaro/>...
Reading symbols from /home/laknoll/dev/qt5/qtmultimedia/examples/videographicsitem/videographicsitem...done.
(gdb) r
Starting program: /home/laknoll/dev/qt5/qtmultimedia/examples/videographicsitem/videographicsitem
[Thread debugging using libthread_db enabled]
Using host libthread_db library "/lib/i386-linux-gnu/libthread_db.so.1".
[New Thread 0xb4967b40 (LWP 8313)]
This plugin does not support setting window opacity
QBackingStore::flush() called with non-exposed window, behavior is undefined
QBackingStore::flush() called with non-exposed window, behavior is undefined
QBackingStore::flush() called with non-exposed window, behavior is undefined
QBackingStore::flush() called with non-exposed window, behavior is undefined
QBackingStore::flush() called with non-exposed window, behavior is undefined
QBackingStore::flush() called with non-exposed window, behavior is undefined
QBackingStore::flush() called with non-exposed window, behavior is undefined
QBackingStore::flush() called with non-exposed window, behavior is undefined
[New Thread 0xb32fdb40 (LWP 8314)]
[Thread 0xb32fdb40 (LWP 8314) exited]
[New Thread 0xb32fdb40 (LWP 8315)]
[New Thread 0xae6d6b40 (LWP 8316)]
[New Thread 0xadcffb40 (LWP 8317)]
[New Thread 0xad2ffb40 (LWP 8318)]
[New Thread 0xabad0b40 (LWP 8319)]
[New Thread 0xaaeffb40 (LWP 8320)]
Failed to start video surface
QBackingStore::flush() called with non-exposed window, behavior is undefined
QBackingStore::flush() called with non-exposed window, behavior is undefined
ASSERT: "widget->isVisible() && widget->updatesEnabled()" in file kernel/qwidgetbackingstore.cpp, line 474

Program received signal SIGABRT, Aborted.
0xb7fdd424 in __kernel_vsyscall ()
(gdb) bt
#0 0xb7fdd424 in __kernel_vsyscall ()
#1 0xb6b5b1ef in __GI_raise (sig=6) at ../nptl/sysdeps/unix/sysv/linux/raise.c:64
#2 0xb6b5e835 in __GI_abort () at abort.c:91
#3 0xb6e5da36 in qt_message_output (msgType=QtFatalMsg, context=..., message=...) at global/qlogging.cpp:701
#4 0xb6e5bac7 in qt_message (msgType=QtFatalMsg, context=..., msg=0xb70ceb88 "ASSERT: \"%s\" in file %s, line %d", ap=0xbfffe518 "H~ȷ8}ȷ\332\001") at global/qlogging.cpp:175
#5 0xb6e5bcdd in QMessageLogger::fatal (this=0xbfffe53c, msg=0xb70ceb88 "ASSERT: \"%s\" in file %s, line %d") at global/qlogging.cpp:247
#6 0xb6e57b88 in qt_assert (assertion=0xb7c87e48 "widget->isVisible() && widget->updatesEnabled()", file=0xb7c87d38 "kernel/qwidgetbackingstore.cpp", line=474)
at global/qglobal.cpp:1921
#7 0xb7859969 in QWidgetBackingStore::markDirty (this=0x81f08d0, rgn=..., widget=0x81e2b88, updateImmediately=false, invalidateBuffer=false) at kernel/qwidgetbackingstore.cpp:474
#8 0xb78bac7c in QWidgetWindow::handleExposeEvent (this=0x81ee690, event=0xbfffebb0) at kernel/qwidgetwindow.cpp:497
#9 0xb78b95bd in QWidgetWindow::event (this=0x81ee690, event=0xbfffebb0) at kernel/qwidgetwindow.cpp:176
#10 0xb784f7d8 in QApplicationPrivate::notify_helper (this=0x8055638, receiver=0x81ee690, e=0xbfffebb0) at kernel/qapplication.cpp:3627
#11 0xb784d0ab in QApplication::notify (this=0xbfffef34, receiver=0x81ee690, e=0xbfffebb0) at kernel/qapplication.cpp:3056
#12 0xb7011653 in QCoreApplication::notifyInternal (this=0xbfffef34, receiver=0x81ee690, event=0xbfffebb0) at kernel/qcoreapplication.cpp:721
#13 0xb736454d in QCoreApplication::sendSpontaneousEvent (receiver=0x81ee690, event=0xbfffebb0) at ../../include/QtCore/../../src/corelib/kernel/qcoreapplication.h:210
#14 0xb7362a61 in QGuiApplicationPrivate::processExposeEvent (e=0x8241e38) at kernel/qguiapplication.cpp:1975
#15 0xb735f0b5 in QGuiApplicationPrivate::processWindowSystemEvent (e=0x8241e38) at kernel/qguiapplication.cpp:1152
#16 0xb73525f0 in QWindowSystemInterface::sendWindowSystemEventsImplementation (flags=...) at kernel/qwindowsysteminterface.cpp:531
#17 0xb735256b in QWindowSystemInterface::sendWindowSystemEvents (flags=...) at kernel/qwindowsysteminterface.cpp:510
#18 0xb4ae782c in userEventSourceDispatch () at eventdispatchers/qeventdispatcher_glib.cpp:76
#19 0xb6312d86 in g_main_context_dispatch () from /lib/i386-linux-gnu/libglib-2.0.so.0
#20 0xb6313125 in ?? () from /lib/i386-linux-gnu/libglib-2.0.so.0
#21 0xb6313201 in g_main_context_iteration () from /lib/i386-linux-gnu/libglib-2.0.so.0
#22 0xb707956a in QEventDispatcherGlib::processEvents (this=0x8057e38, flags=...) at kernel/qeventdispatcher_glib.cpp:423
#23 0xb700e963 in QEventLoop::processEvents (this=0xbfffee9c, flags=...) at kernel/qeventloop.cpp:135
#24 0xb700ec1a in QEventLoop::exec (this=0xbfffee9c, flags=...) at kernel/qeventloop.cpp:211
#25 0xb7011cf4 in QCoreApplication::exec () at kernel/qcoreapplication.cpp:973
#26 0xb735ed7d in QGuiApplication::exec () at kernel/qguiapplication.cpp:1031
#27 0xb784cd60 in QApplication::exec () at kernel/qapplication.cpp:2946
#28 0x0804c82d in main (argc=1, argv=0xbfffefe4) at main.cpp:52