Version: KDE 4.4 RC2 (using Devel) OS: Linux Installed from: Compiled sources ** Bug Description ** With both KDE 4.4 RC1 and RC2, I have experienced occasional Plasma crashes (segfault). The common scenario for the crash's occurance seems to be this: 1) I have three copies of an application open, and all three instances are grouped as a single taskbar entry. 2) I close one of the three instances of the program 3) Plasma crashes (black desktop with no panel) ** Reproducing the Bug ** I haven't been able to reproduce this consistently (it only seems to happen when I'm just working along on my system, not when I'm trying to reproduce the bug). I'll post back if I can find a way to consistently reproduce this. I don't know how to get the debugging symbols installed with the Ubuntu packages, so my backtrace is probably of no use, but here it is anyway: Application: Plasma Workspace (kdeinit4), signal: Segmentation fault [Current thread is 1 (Thread 0xb77d7760 (LWP 3245))] Thread 2 (Thread 0xac677b70 (LWP 3246)): #0 0x00615422 in __kernel_vsyscall () #1 0x00273e15 in pthread_cond_wait@@GLIBC_2.3.2 () from /lib/tls/i686/cmov/libpthread.so.0 #2 0x014ee307 in QWaitCondition::wait(QMutex*, unsigned long) () from /usr/lib/libQtCore.so.4 #3 0x05e2d102 in ?? () from /usr/lib/libQtNetwork.so.4 #4 0x014ed3ae in ?? () from /usr/lib/libQtCore.so.4 #5 0x0026f80e in start_thread () from /lib/tls/i686/cmov/libpthread.so.0 #6 0x00bea8de in clone () from /lib/tls/i686/cmov/libc.so.6 Thread 1 (Thread 0xb77d7760 (LWP 3245)): [KCrash Handler] #6 0x04dc2916 in ?? () from /usr/lib/libQtGui.so.4 #7 0x04dc3aae in ?? () from /usr/lib/libQtGui.so.4 #8 0x04d9831b in QGraphicsScene::items(QRectF const&, Qt::ItemSelectionMode, Qt::SortOrder, QTransform const&) const () from /usr/lib/libQtGui.so.4 #9 0x04d9fa55 in ?? () from /usr/lib/libQtGui.so.4 #10 0x04d9ff20 in ?? () from /usr/lib/libQtGui.so.4 #11 0x04da01d8 in QGraphicsScene::mouseMoveEvent(QGraphicsSceneMouseEvent*) () from /usr/lib/libQtGui.so.4 #12 0x04daf3cd in QGraphicsScene::event(QEvent*) () from /usr/lib/libQtGui.so.4 #13 0x0470a19c in QApplicationPrivate::notify_helper(QObject*, QEvent*) () from /usr/lib/libQtGui.so.4 #14 0x04710df7 in QApplication::notify(QObject*, QEvent*) () from /usr/lib/libQtGui.so.4 #15 0x00eeea1a in KApplication::notify(QObject*, QEvent*) () from /usr/lib/libkdeui.so.5 #16 0x015eeeab in QCoreApplication::notifyInternal(QObject*, QEvent*) () from /usr/lib/libQtCore.so.4 #17 0x0470b07e in ?? () from /usr/lib/libQtGui.so.4 #18 0x04dcf852 in ?? () from /usr/lib/libQtGui.so.4 #19 0x04dcfa96 in QGraphicsView::mouseMoveEvent(QMouseEvent*) () from /usr/lib/libQtGui.so.4 #20 0x04766fd6 in QWidget::event(QEvent*) () from /usr/lib/libQtGui.so.4 #21 0x04b60433 in QFrame::event(QEvent*) () from /usr/lib/libQtGui.so.4 #22 0x04bf9cf2 in QAbstractScrollArea::viewportEvent(QEvent*) () from /usr/lib/libQtGui.so.4 #23 0x04dcd39b in QGraphicsView::viewportEvent(QEvent*) () from /usr/lib/libQtGui.so.4 #24 0x04bfc5e5 in ?? () from /usr/lib/libQtGui.so.4 #25 0x015ee14a in QCoreApplicationPrivate::sendThroughObjectEventFilters(QObject*, QEvent*) () from /usr/lib/libQtCore.so.4 #26 0x0470a179 in QApplicationPrivate::notify_helper(QObject*, QEvent*) () from /usr/lib/libQtGui.so.4 #27 0x0471176b in QApplication::notify(QObject*, QEvent*) () from /usr/lib/libQtGui.so.4 #28 0x00eeea1a in KApplication::notify(QObject*, QEvent*) () from /usr/lib/libkdeui.so.5 #29 0x015eeeab in QCoreApplication::notifyInternal(QObject*, QEvent*) () from /usr/lib/libQtCore.so.4 #30 0x0471071f in QApplicationPrivate::sendMouseEvent(QWidget*, QMouseEvent*, QWidget*, QWidget*, QWidget**, QPointer<QWidget>&, bool) () from /usr/lib/libQtGui.so.4 #31 0x04799d18 in ?? () from /usr/lib/libQtGui.so.4 #32 0x047991f1 in QApplication::x11ProcessEvent(_XEvent*) () from /usr/lib/libQtGui.so.4 #33 0x047c804a in ?? () from /usr/lib/libQtGui.so.4 #34 0x07bdce88 in g_main_context_dispatch () from /lib/libglib-2.0.so.0 #35 0x07be0730 in ?? () from /lib/libglib-2.0.so.0 #36 0x07be0863 in g_main_context_iteration () from /lib/libglib-2.0.so.0 #37 0x0161abd5 in QEventDispatcherGlib::processEvents(QFlags<QEventLoop::ProcessEventsFlag>) () from /usr/lib/libQtCore.so.4 #38 0x047c7b75 in ?? () from /usr/lib/libQtGui.so.4 #39 0x015ed4c9 in QEventLoop::processEvents(QFlags<QEventLoop::ProcessEventsFlag>) () from /usr/lib/libQtCore.so.4 #40 0x015ed91a in QEventLoop::exec(QFlags<QEventLoop::ProcessEventsFlag>) () from /usr/lib/libQtCore.so.4 #41 0x015f1b0f in QCoreApplication::exec() () from /usr/lib/libQtCore.so.4 #42 0x0470a237 in QApplication::exec() () from /usr/lib/libQtGui.so.4 #43 0x013c61ee in kdemain () from /usr/lib/libkdeinit4_plasma-desktop.so #44 0x0804dff7 in _start () ** My System ** Motherboard: MSI K9N SLI Platinum (nForce 570 SLI chipset) CPU: AMD Athlon(tm) 64 Processor 4000+ (2.6 GHz) RAM: 2GB DDR2 Video: Dell NVIDIA GeForce 7800 GTX w/ 256 MB RAM (PCI Express) OS: Kubuntu 9.10 i386 (with KDE 4.4 RC2) Linux Kernel: 2.6.31-9-rt NVIDIA driver: 185.18.36 Screen Resolution: 1280 x 960 X.org: 7.4 Qt version: 4.6
Okay, I have figured out how to 100% reproduce this on my system: 1) To have this work exactly as described, make sure your taskbar can hold four entries across before grouping occurs. My system is set at 1280x960 resolution, but I also have a certain number of launchers and icons, so YMMV. 2) My taskbar is set to manual sorting--I'm not sure if this makes a difference. 3) Close all applications (so there is nothing in the taskbar). 4) Open and minimize Dolphin. 5) Open and minimize Konqueror. 6) Open and minimize three copies of Kwrite (the third Kwrite instance should cause all Kwrite instances to be grouped). 7) Close one instance of Kwrite. 8) Close Konqueror. At this point, plasma segfaults as the remaining two Kwrite instances are to be split out into their own taskbar entries.
Can you install the full debug symbols of Qt (your debug package) so i can i have a full backtrace? Thank you.
Here's the full backtrace: Application: Plasma Workspace (kdeinit4), signal: Segmentation fault [Current thread is 1 (Thread 0xb775d760 (LWP 2473))] Thread 2 (Thread 0xab66bb70 (LWP 2474)): #0 0x00b5d422 in __kernel_vsyscall () #1 0x00379e15 in pthread_cond_wait@@GLIBC_2.3.2 () from /lib/tls/i686/cmov/libpthread.so.0 #2 0x01027307 in QWaitConditionPrivate::wait (this=0x9e099a0, mutex=0x9e0999c, time=4294967295) at thread/qwaitcondition_unix.cpp:87 #3 QWaitCondition::wait (this=0x9e099a0, mutex=0x9e0999c, time=4294967295) at thread/qwaitcondition_unix.cpp:159 #4 0x04e26102 in QHostInfoAgent::run (this=0x9e09990) at kernel/qhostinfo.cpp:252 #5 0x010263ae in QThreadPrivate::start (arg=0x9e09990) at thread/qthread_unix.cpp:244 #6 0x0037580e in start_thread () from /lib/tls/i686/cmov/libpthread.so.0 #7 0x006018de in clone () from /lib/tls/i686/cmov/libc.so.6 Thread 1 (Thread 0xb775d760 (LWP 2473)): [KCrash Handler] #6 QGraphicsScenePrivate::processDirtyItemsRecursive (this=0x9a428a0, item=0xa2bc290, dirtyAncestorContainsChildren=false, parentOpacity=1) at graphicsview/qgraphicsscene.cpp:4895 #7 0x01a1beed in QGraphicsScenePrivate::_q_processDirtyItems (this=0x9a428a0) at graphicsview/qgraphicsscene.cpp:466 #8 0x01a1c4f6 in QGraphicsScene::qt_metacall (this=0x9a7c430, _c=QMetaObject::InvokeMetaMethod, _id=14, _a=0xa6ee9a0) at .moc/release-shared/moc_qgraphicsscene.cpp:130 #9 0x0206c68a in Plasma::Corona::qt_metacall(QMetaObject::Call, int, void**) () from /usr/lib/libplasma.so.3 #10 0x054d75aa in ?? () from /usr/lib/libkdeinit4_plasma-desktop.so #11 0x0112d11a in QMetaObject::metacall (object=0x9a7c430, cl=QMetaObject::InvokeMetaMethod, idx=18, argv=0x0) at kernel/qmetaobject.cpp:237 #12 0x01137856 in QMetaCallEvent::placeMetaCall (this=0x9da4980, object=0x9a7c430) at kernel/qobject.cpp:574 #13 0x011388ae in QObject::event (this=0x9a7c430, e=0x9da4980) at kernel/qobject.cpp:1260 #14 0x01a181c4 in QGraphicsScene::event (this=0x9a7c430, event=0x9da4980) at graphicsview/qgraphicsscene.cpp:3450 #15 0x0137319c in QApplicationPrivate::notify_helper (this=0x99cf870, receiver=0x9a7c430, e=0x9da4980) at kernel/qapplication.cpp:4242 #16 0x01379df7 in QApplication::notify (this=0x99c96c0, receiver=0x9a7c430, e=0x9da4980) at kernel/qapplication.cpp:3661 #17 0x00de8a1a in KApplication::notify(QObject*, QEvent*) () from /usr/lib/libkdeui.so.5 #18 0x01127eab in QCoreApplication::notifyInternal (this=0x99c96c0, receiver=0x9a7c430, event=0x9da4980) at kernel/qcoreapplication.cpp:704 #19 0x0112a8e3 in QCoreApplication::sendEvent (receiver=0x0, event_type=0, data=0x99680d8) at ../../include/QtCore/../../src/corelib/kernel/qcoreapplication.h:215 #20 QCoreApplicationPrivate::sendPostedEvents (receiver=0x0, event_type=0, data=0x99680d8) at kernel/qcoreapplication.cpp:1345 #21 0x0112aa4d in QCoreApplication::sendPostedEvents (receiver=0x0, event_type=0) at kernel/qcoreapplication.cpp:1238 #22 0x011540df in QCoreApplication::sendPostedEvents (s=0x99d1bc0) at ../../include/QtCore/../../src/corelib/kernel/qcoreapplication.h:220 #23 postEventSourceDispatch (s=0x99d1bc0) at kernel/qeventdispatcher_glib.cpp:276 #24 0x052b6e88 in g_main_context_dispatch () from /lib/libglib-2.0.so.0 #25 0x052ba730 in ?? () from /lib/libglib-2.0.so.0 #26 0x052ba863 in g_main_context_iteration () from /lib/libglib-2.0.so.0 #27 0x01153bd5 in QEventDispatcherGlib::processEvents (this=0x99cf660, flags=...) at kernel/qeventdispatcher_glib.cpp:407 #28 0x01430b75 in QGuiEventDispatcherGlib::processEvents (this=0x99cf660, flags=...) at kernel/qguieventdispatcher_glib.cpp:202 #29 0x011264c9 in QEventLoop::processEvents (this=0xbfa44d14, flags=) at kernel/qeventloop.cpp:149 #30 0x0112691a in QEventLoop::exec (this=0xbfa44d14, flags=...) at kernel/qeventloop.cpp:201 #31 0x0112ab0f in QCoreApplication::exec () at kernel/qcoreapplication.cpp:981 #32 0x01373237 in QApplication::exec () at kernel/qapplication.cpp:3570 #33 0x054df1ee in kdemain () from /usr/lib/libkdeinit4_plasma-desktop.so #34 0x0804dff7 in _start ()
This is a Qt 4.6.0 bug, fixed in 4.6.1. Regards *** This bug has been marked as a duplicate of bug 210146 ***