Application crash when dock widget is closed

Thread 1 (Thread 0xb7fc7780 (LWP 14119)):
#0 end (this=0x886c018, step=0) at animation/qvariantanimation.cpp:308
#1 QVariantAnimationPrivate::valueAt (this=0x886c018, step=0) at animation/qvariantanimation.cpp:308
#2 0x015539f3 in QVariantAnimation::keyValueAt (this=0x890bed8, step=0) at animation/qvariantanimation.cpp:566
#3 0x01553a6f in QVariantAnimation::startValue (this=0x890bed8) at animation/qvariantanimation.cpp:530
#4 0x01556e5a in QPropertyAnimation::updateState (this=0x890bed8, newState=QAbstractAnimation::Running, oldState=QAbstractAnimation::Stopped) at animation/qpropertyanimation.cpp:287
#5 0x0155158e in QAbstractAnimationPrivate::setState (this=0x891b270, newState=QAbstractAnimation::Running) at animation/qabstractanimation.cpp:380
#6 0x010add68 in QWidgetAnimator::animate (this=0x8473f88, widget=0x86474d8, _final_geometry=..., animate=112) at widgets/qwidgetanimator.cpp:102
#7 0x00ffe8fa in QDockAreaLayout::apply (this=0x8473bb4, animate=false) at widgets/qdockarealayout.cpp:3084
#8 0x01027172 in QMainWindowLayoutState::apply (this=0x8473b08, animated=false) at widgets/qmainwindowlayout.cpp:235
#9 0x010285f6 in QMainWindowLayout::applyState (this=0x8473af8, newState=..., animate=false) at widgets/qmainwindowlayout.cpp:1925
#10 0x01028eb0 in QMainWindowLayout::setGeometry (this=0x8473af8, _r=...) at widgets/qmainwindowlayout.cpp:1473
#11 0x00c0a19f in QLayoutPrivate::doResize (this=0x8474658, r=...) at kernel/qlayout.cpp:681
#12 0x00c0a2c7 in QLayout::activate (this=0x8473af8) at kernel/qlayout.cpp:1259
#13 0x00c0b083 in QLayout::widgetEvent (this=0x8473af8, e=0x890c360) at kernel/qlayout.cpp:752
#14 0x00bd9d36 in QApplicationPrivate::notify_helper (this=0x8428038, receiver=0xbfff9450, e=0x890c360) at kernel/qapplication.cpp:4313
#15 0x00be0079 in QApplication::notify (this=0xbffff548, receiver=0xbfff9450, e=0x890c360) at kernel/qapplication.cpp:4287
#16 0x016643db in QCoreApplication::notifyInternal (this=0xbffff548, receiver=0xbfff9450, event=0x890c360) at kernel/qcoreapplication.cpp:704
#17 0x01667dcb in sendEvent (receiver=0x0, event_type=0, data=0x8426380) at ../../include/QtCore/../../src/corelib/kernel/qcoreapplication.h:215
#18 QCoreApplicationPrivate::sendPostedEvents (receiver=0x0, event_type=0, data=0x8426380) at kernel/qcoreapplication.cpp:1345
#19 0x01667f2d in QCoreApplication::sendPostedEvents (receiver=0x0, event_type=0) at kernel/qcoreapplication.cpp:1238
#20 0x0168e74f in sendPostedEvents (s=0x842ad10) at ../../include/QtCore/../../src/corelib/kernel/qcoreapplication.h:220
#21 postEventSourceDispatch (s=0x842ad10) at kernel/qeventdispatcher_glib.cpp:276
#22 0x021efc78 in g_main_context_dispatch () from /lib/libglib-2.0.so.0
#23 0x021f35e0 in ?? () from /lib/libglib-2.0.so.0
#24 0x021f36f4 in g_main_context_iteration () from /lib/libglib-2.0.so.0
#25 0x0168e245 in QEventDispatcherGlib::processEvents (this=0x84289b0, flags=...) at kernel/qeventdispatcher_glib.cpp:412
#26 0x00c89455 in QGuiEventDispatcherGlib::processEvents (this=0x84289b0, flags=...) at kernel/qguieventdispatcher_glib.cpp:204
#27 0x01662fc9 in QEventLoop::processEvents (this=0xbfff93f4, flags=...) at kernel/qeventloop.cpp:149
#28 0x016632fa in QEventLoop::exec (this=0xbfff93f4, flags=...) at kernel/qeventloop.cpp:201
#29 0x01667fef in QCoreApplication::exec () at kernel/qcoreapplication.cpp:981
#30 0x00bd8ff7 in QApplication::exec () at kernel/qapplication.cpp:3601
#31 0x080bccd0 in main (argc=1, argv=0xbffff614) at main.cpp:10