This looks like a recent regression. I noticed it for the first time maybe when bug 305875 was introduced, and encountered it for another two or three times afterward. Today I finally find out how to reproduce it 100%, as described in the title. I built kwin from the current HEAD ( 883628749ac942b486ecf32a5dbbec0fda6a0b57 ) I'm using nouveau 1.0.1 and kernel-3.5.3 . Haven't tried the official nvidia driver, if that matters. Here is the backtrace obtained after the freeze : #0 0xb76bd988 in deref (this=<optimized out>) at /usr/include/qt4/QtCore/qatomic_i386.h:127 #1 ~QList (this=<optimized out>, this=<optimized out>, this=<optimized out>) at /usr/include/qt4/QtCore/qlist.h:731 #2 QListIterator (this=<optimized out>, this=<optimized out>, this=<optimized out>, container=..., this=<optimized out>, container=...) at /usr/include/qt4/QtCore/qlist.h:730 #3 KWin::TabBox::TabBoxHandlerImpl::checkApplications (this=<optimized out>, client=0x961f498) at /tmp/portage/kde-base/kwin-9999/work/kwin-9999/kwin/tabbox/tabbox.cpp:165 #4 0xb76be0d2 in KWin::TabBox::TabBoxHandlerImpl::clientToAddToList (this=<optimized out>, client=<error reading variable: Unhandled dwarf expression opcode 0x0>, desktop=<optimized out>) at /tmp/portage/kde-base/kwin-9999/work/kwin-9999/kwin/tabbox/tabbox.cpp:236 #5 0xb76cabcb in KWin::TabBox::ClientModel::createClientList (this=<optimized out>, desktop=<optimized out>, partialReset=<error reading variable: Unhandled dwarf expression opcode 0x0>) at /tmp/portage/kde-base/kwin-9999/work/kwin-9999/kwin/tabbox/clientmodel.cpp:173 #6 0xb76ca5c0 in KWin::TabBox::ClientModel::createClientList (this=0x8f8c5e8, partialReset=<optimized out>) at /tmp/portage/kde-base/kwin-9999/work/kwin-9999/kwin/tabbox/clientmodel.cpp:145 #7 0xb76d2734 in KWin::TabBox::TabBoxHandler::createModel (this=<error reading variable: Unhandled dwarf expression opcode 0x0>, partialReset=<error reading variable: Unhandled dwarf expression opcode 0x2>) at /tmp/portage/kde-base/kwin-9999/work/kwin-9999/kwin/tabbox/tabboxhandler.cpp:454 #8 0xb76c22a9 in KWin::TabBox::TabBox::reset (this=<error reading variable: Unhandled dwarf expression opcode 0xdd>, partial_reset=<error reading variable: Unhandled dwarf expression opcode 0x7>) at /tmp/portage/kde-base/kwin-9999/work/kwin-9999/kwin/tabbox/tabbox.cpp:539 #9 0xb76c49c5 in KWin::TabBox::TabBox::startKDEWalkThroughWindows (this=<optimized out>, mode=<error reading variable: Unhandled dwarf expression opcode 0x7>) at /tmp/portage/kde-base/kwin-9999/work/kwin-9999/kwin/tabbox/tabbox.cpp:1177 #10 0xb76c4176 in KWin::TabBox::TabBox::navigatingThroughWindows (this=<optimized out>, forward=<optimized out>, shortcut=<error reading variable: Unhandled dwarf expression opcode 0xc8>, mode=<error reading variable: Unhandled dwarf expression opcode 0x1>) at /tmp/portage/kde-base/kwin-9999/work/kwin-9999/kwin/tabbox/tabbox.cpp:907 #11 0xb76c7e0c in slotWalkThroughWindows (this=<error reading variable: Unhandled dwarf expression opcode 0x0>) at /tmp/portage/kde-base/kwin-9999/work/kwin-9999/kwin/tabbox/tabbox.cpp:921 #12 KWin::TabBox::TabBox::qt_static_metacall (_o=<optimized out>, _c=QMetaObject::InvokeMetaMethod, _id=<error reading variable: Unhandled dwarf expression opcode 0x7>, _a=<error reading variable: Unhandled dwarf expression opcode 0x0>) at /tmp/portage/kde-base/kwin-9999/work/kwin-9999_build/kwin/tabbox.moc:153 #13 0xb5e92761 in QMetaObject::activate (sender=0x8f56040, m=0xb5cbea78 <QAction::staticMetaObject>, local_signal_index=1, argv=0xbfded868) at kernel/qobject.cpp:3547 #14 0xb537a3ad in QAction::triggered (this=0x8f56040, _t1=false) at .moc/release-shared/moc_qaction.cpp:277 #15 0xb537a64b in QAction::activate (this=0x8f56040, event=QAction::Trigger) at kernel/qaction.cpp:1257 #16 0xb7195d0f in trigger (this=0x8f56040) at /usr/include/qt4/QtGui/qaction.h:218 #17 KGlobalAccelPrivate::_k_invokeAction (this=0x8f8e130, componentUnique=..., actionUnique=..., timestamp=69834425) at /mnt/personal/build/portage/kde-base/kdelibs-9999/work/kdelibs-9999/kdeui/shortcuts/kglobalaccel.cpp:449 #18 0xb7196c46 in qt_static_metacall (_a=0xbfdeda30, _o=0x8f6ce10, _c=<optimized out>, _id=<optimized out>) at /mnt/personal/build/portage/kde-base/kdelibs-9999/work/kdelibs-9999_build/kdeui/kglobalaccel.moc:54 #19 KGlobalAccel::qt_static_metacall (_o=0x8f6ce10, _c=QMetaObject::InvokeMetaMethod, _id=0, _a=0xbfdeda30) at /mnt/personal/build/portage/kde-base/kdelibs-9999/work/kdelibs-9999_build/kdeui/kglobalaccel.moc:48 #20 0xb5e92761 in QMetaObject::activate (sender=0x8f6fa08, m=0xb7399598 <OrgKdeKglobalaccelComponentInterface::staticMetaObject>, local_signal_index=0, argv=0xbfdeda30) at kernel/qobject.cpp:3547 #21 0xb72d2f05 in OrgKdeKglobalaccelComponentInterface::globalShortcutPressed (this=0x8f6fa08, _t1=..., _t2=..., _t3=69834425) at /mnt/personal/build/portage/kde-base/kdelibs-9999/work/kdelibs-9999_build/kdeui/kglobalaccel_component_interface.moc:164 #22 0xb72d364e in qt_static_metacall (_a=0xbfdedc08, _id=0, _o=0x8f6fa08, _c=<optimized out>) at /mnt/personal/build/portage/kde-base/kdelibs-9999/work/kdelibs-9999_build/kdeui/kglobalaccel_component_interface.moc:75 #23 OrgKdeKglobalaccelComponentInterface::qt_static_metacall (_o=0x8f6fa08, _c=QMetaObject::InvokeMetaMethod, _id=0, _a=0xbfdedc08) at /mnt/personal/build/portage/kde-base/kdelibs-9999/work/kdelibs-9999_build/kdeui/kglobalaccel_component_interface.moc:69 #24 0xb72d3bfc in OrgKdeKglobalaccelComponentInterface::qt_metacall (this=0x8f6fa08, _c=QMetaObject::InvokeMetaMethod, _id=0, _a=0xbfdedc08) at /mnt/personal/build/portage/kde-base/kdelibs-9999/work/kdelibs-9999_build/kdeui/kglobalaccel_component_interface.moc:130 #25 0xb5ffa565 in ?? () from /usr/lib/qt4/libQtDBus.so.4 #26 0xb60047dd in ?? () from /usr/lib/qt4/libQtDBus.so.4 #27 0xb5e96d0b in QObject::event (this=0x8f6fa08, e=0x9553260) at kernel/qobject.cpp:1195 #28 0xb5381cf4 in notify_helper (e=0x9553260, receiver=0x8f6fa08, this=0x8e04658) at kernel/qapplication.cpp:4557 #29 QApplicationPrivate::notify_helper (this=0x8e04658, receiver=0x8f6fa08, e=0x9553260) at kernel/qapplication.cpp:4529 #30 0xb5387b4a in QApplication::notify (this=0x9553260, receiver=0x8f6fa08, e=0x9553260) at kernel/qapplication.cpp:4286 #31 0xb7142ec1 in KApplication::notify (this=0xbfdee4b8, receiver=0x8f6fa08, event=0x9553260) at /mnt/personal/build/portage/kde-base/kdelibs-9999/work/kdelibs-9999/kdeui/kernel/kapplication.cpp:311 #32 0xb75de48e in KWin::Application::notify ( this=<error reading variable: DWARF-2 expression error: DW_OP_reg operations must be used either alone or in conjunction with DW_OP_piece or DW_OP_bit_piece.>, o=<error reading variable: Unhandled dwarf expression opcode 0x2>, e=<error reading variable: Unhandled dwarf expression opcode 0x2>) at /tmp/portage/kde-base/kwin-9999/work/kwin-9999/kwin/main.cpp:371 #33 0xb5e7bf5e in QCoreApplication::notifyInternal (this=0xbfdee4b8, receiver=0x8f6fa08, event=0x9553260) at kernel/qcoreapplication.cpp:915 #34 0xb5e7fb30 in sendEvent (event=<optimized out>, receiver=<optimized out>) at kernel/qcoreapplication.h:231 #35 QCoreApplicationPrivate::sendPostedEvents (receiver=0x0, event_type=0, data=0x8dba130) at kernel/qcoreapplication.cpp:1539 #36 0xb5e7fe6c in QCoreApplication::sendPostedEvents (receiver=0x0, event_type=0) at kernel/qcoreapplication.cpp:1432 #37 0xb543536a in sendPostedEvents () at ../../include/QtCore/../../src/corelib/kernel/qcoreapplication.h:236 #38 QEventDispatcherX11::processEvents (this=0x8dbaea0, flags=...) at kernel/qeventdispatcher_x11.cpp:75 #39 0xb5e7a80d in QEventLoop::processEvents (this=0xbfdee3c4, flags=...) at kernel/qeventloop.cpp:149 #40 0xb5e7aaa9 in QEventLoop::exec (this=0xbfdee3c4, flags=...) at kernel/qeventloop.cpp:204 #41 0xb5e7ff1a in QCoreApplication::exec () at kernel/qcoreapplication.cpp:1187 #42 0xb537f3b4 in QApplication::exec () at kernel/qapplication.cpp:3818 #43 0xb75dfc60 in kdemain (argc=<optimized out>, argv=<optimized out>) at /tmp/portage/kde-base/kwin-9999/work/kwin-9999/kwin/main.cpp:545 #44 0xb73bc597 in __libc_start_main (main=0x8048710 <main(int, char**)>, argc=1, ubp_av=0xbfdee804, init=0x8048720 <__libc_csu_init>, fini=0x8048780 <__libc_csu_fini>, rtld_fini=0xb778f3b0 <_dl_fini>, stack_end=0xbfdee7fc) at libc-start.c:226 #45 0x08048641 in _start () at ../sysdeps/i386/elf/start.S:119 Reproducible: Always Steps to Reproduce: 1. Choose the "cover switch" effect for switching window 2. go to an empty virtual desktop and press Alt+Tab Actual Results: kwin freezes Expected Results: it should not freeze
$ qdbus org.kde.kwin /KWin supportInformation KWin Support Information: The following information should be used when requesting support on e.g. http://forum.kde.org. It provides information about the currently running instance, which options are used, what OpenGL driver and which effects are running. Please post the information provided underneath this introductory text to a paste bin service like http://paste.kde.org instead of pasting into support threads. ========================== Options ======= focusPolicy: 0 nextFocusPrefersMouse: false clickRaise: true autoRaise: false autoRaiseInterval: 0 delayFocusInterval: 0 shadeHover: false shadeHoverInterval: 250 separateScreenFocus: false activeMouseScreen: false placement: 4 focusPolicyIsReasonable: true borderSnapZone: 10 windowSnapZone: 10 centerSnapZone: 0 snapOnlyWhenOverlapping: false showDesktopIsMinimizeAll: false rollOverDesktops: true focusStealingPreventionLevel: 2 legacyFullscreenSupport: false operationTitlebarDblClick: commandActiveTitlebar1: 0 commandActiveTitlebar2: 30 commandActiveTitlebar3: 2 commandInactiveTitlebar1: 4 commandInactiveTitlebar2: 30 commandInactiveTitlebar3: 2 commandWindow1: 7 commandWindow2: 8 commandWindow3: 8 commandWindowWheel: 31 commandAll1: 10 commandAll2: 3 commandAll3: 14 keyCmdAllModKey: 16777251 showGeometryTip: false electricBorders: false electricBorderDelay: 150 electricBorderCooldown: 350 electricBorderPushbackPixels: 1 electricBorderMaximize: false electricBorderTiling: false borderlessMaximizedWindows: false killPingTimeout: 5000 hideUtilityWindowsForInactive: true inactiveTabsSkipTaskbar: false autogroupSimilarWindows: false autogroupInForeground: true compositingMode: 1 useCompositing: true compositingInitialized: true hiddenPreviews: 1 unredirectFullscreen: false glSmoothScale: 1 glVSync: true xrenderSmoothScale: false maxFpsInterval: 17 refreshRate: 0 vBlankTime: 6144 glDirect: true glStrictBinding: true glStrictBindingFollowsDriver: true Compositing =========== Qt Graphics System: raster Compositing is active Compositing Type: OpenGL OpenGL vendor string: nouveau OpenGL renderer string: Gallium 0.4 on NV86 OpenGL version string: 3.0 Mesa 9.0-devel Driver: Nouveau GPU class: G80/G90 OpenGL version: 3.0 Mesa version: 9.0 X server version: 1.12.99 Linux kernel version: 3.5.3 Direct rendering: yes Requires strict binding: yes GLSL shaders: yes Texture NPOT support: yes OpenGL 2 Shaders are used Loaded Effects: --------------- kwin4_effect_zoom kwin4_effect_login kwin4_effect_slidingpopups kwin4_effect_coverswitch kwin4_effect_translucency kwin4_effect_screenshot kwin4_effect_slide kwin4_effect_diminactive kwin4_effect_fade kwin4_effect_dialogparent kwin4_effect_taskbarthumbnail kwin4_effect_presentwindows kwin4_effect_blur kwin4_effect_dashboard Currently Active Effects: ------------------------- kwin4_effect_translucency kwin4_effect_diminactive kwin4_effect_blur Effect Settings: ---------------- kwin4_effect_zoom: zoomFactor: 1.25 mousePointer: 0 mouseTracking: 0 enableFocusTracking: false followFocus: true focusDelay: 350 moveFactor: 20 targetZoom: 1 kwin4_effect_login: fadeToBlack: false kwin4_effect_slidingpopups: fadeInTime: 125 fadeOutTime: 125 kwin4_effect_coverswitch: animationDuration: 100 animateSwitch: true animateStart: true animateStop: true reflection: true windowTitle: true zPosition: 592 dynamicThumbnails: true thumbnailWindows: 8 primaryTabBox: true secondaryTabBox: false kwin4_effect_translucency: decoration: 1 moveResize: 0.8 dialogs: 1 inactive: 1 comboboxPopups: 1 menus: 1 individualMenuConfig: false dropDownMenus: 1 popupMenus: 1 tornOffMenus: 1 moveResizeDuration: 400 activeInactiveDuration: 400 kwin4_effect_screenshot: kwin4_effect_slide: kwin4_effect_diminactive: dimPanels: false dimDesktop: false dimKeepAbove: false dimByGroup: true dimStrength: 25 kwin4_effect_fade: kwin4_effect_dialogparent: changeTime: 150 kwin4_effect_taskbarthumbnail: kwin4_effect_presentwindows: layoutMode: 0 showCaptions: true showIcons: true doNotCloseWindows: false ignoreMinimized: false accuracy: 20 fillGaps: true fadeDuration: 75 showPanel: false leftButtonWindow: 1 rightButtonWindow: 2 middleButtonWindow: 0 leftButtonDesktop: 2 middleButtonDesktop: 0 rightButtonDesktop: 0 dragToClose: false kwin4_effect_blur: blurRadius: 12 cacheTexture: true kwin4_effect_dashboard: brightness: 0.5 saturation: 0.5 blur: false
sure it's not bug #306260 (ie. how recent is your version and is the patch merged to master? (no access to my build sys atm.))
> is the patch > merged to master? (no access to my build sys atm.)) no
I merged KDE/4.9 into master, so please test again.
No freezing now. Thanks
*** This bug has been marked as a duplicate of bug 306260 ***