Application: plasma-desktop (0.4)
KDE Platform Version: 4.6.90 (4.7 RC1)
Qt Version: 4.7.3
Operating System: Linux 3.0.0-6-generic x86_64
Distribution: Ubuntu oneiric (development branch)

-- Information about the crash:
- What I was doing when the application crashed:
Added the default panel to the desk top or adding a system tray widget to the desktop 

- Unusual behavior I noticed:
no windows would show up on the desk top.  I could generate windows (from the context menu, adding a launcher widget to the desktop, from alt-f2 etc).  Using present would display the windows I thought were open.  When plasma-desktop crashed I could see my windows briefly, but when it respawned the windows were inaccessible again. 

By killing plasma-desktop (via ssh from another computer) I could access the windows to submit this report.

- other issues
I am on the ubuntu 10.11 alpha. 
I am having trouble with nvidia drivers + twin view. + xorg finding screens.  I don't think that those issues are related, but mentioning it just in case.

The crash can be reproduced every time.

-- Backtrace:
Application: Plasma Desktop Shell (plasma-desktop), signal: Segmentation fault
[Current thread is 1 (Thread 0x7f7c4a9d77c0 (LWP 4523))]

Thread 4 (Thread 0x7f7c257e8700 (LWP 4526)):
#0  0x00007f7c4a2c4093 in __poll (fds=<value optimized out>, nfds=<value optimized out>, timeout=<value optimized out>) at ../sysdeps/unix/sysv/linux/poll.c:87
#1  0x00007f7c3e8a61c8 in ?? () from /lib/x86_64-linux-gnu/libglib-2.0.so.0
#2  0x00007f7c3e8a6689 in g_main_context_iteration () from /lib/x86_64-linux-gnu/libglib-2.0.so.0
#3  0x00007f7c474b97ae in QEventDispatcherGlib::processEvents (this=0x2dfbc20, flags=<value optimized out>) at kernel/qeventdispatcher_glib.cpp:424
#4  0x00007f7c4748dc62 in QEventLoop::processEvents (this=<value optimized out>, flags=...) at kernel/qeventloop.cpp:149
#5  0x00007f7c4748de67 in QEventLoop::exec (this=0x7f7c257e7cd0, flags=...) at kernel/qeventloop.cpp:201
#6  0x00007f7c473a52cf in QThread::exec (this=<value optimized out>) at thread/qthread.cpp:492
#7  0x00007f7c47470c2f in QInotifyFileSystemWatcherEngine::run (this=0x2e003e0) at io/qfilesystemwatcher_inotify.cpp:248
#8  0x00007f7c473a7d55 in QThreadPrivate::start (arg=0x2e003e0) at thread/qthread_unix.cpp:320
#9  0x00007f7c3bbc8bc3 in ?? () from /usr/lib/nvidia-current/libGL.so.1
#10 0x00007f7c3f3abd8c in start_thread (arg=0x7f7c257e8700) at pthread_create.c:304
#11 0x00007f7c4a2d11dd in clone () at ../sysdeps/unix/sysv/linux/x86_64/clone.S:112
#12 0x0000000000000000 in ?? ()

Thread 3 (Thread 0x7f7c19ce7700 (LWP 4527)):
#0  0x00007f7c4a2c4093 in __poll (fds=<value optimized out>, nfds=<value optimized out>, timeout=<value optimized out>) at ../sysdeps/unix/sysv/linux/poll.c:87
#1  0x00007f7c3e8a61c8 in ?? () from /lib/x86_64-linux-gnu/libglib-2.0.so.0
#2  0x00007f7c3e8a6689 in g_main_context_iteration () from /lib/x86_64-linux-gnu/libglib-2.0.so.0
#3  0x00007f7c474b97ae in QEventDispatcherGlib::processEvents (this=0x1926250, flags=<value optimized out>) at kernel/qeventdispatcher_glib.cpp:424
#4  0x00007f7c4748dc62 in QEventLoop::processEvents (this=<value optimized out>, flags=...) at kernel/qeventloop.cpp:149
#5  0x00007f7c4748de67 in QEventLoop::exec (this=0x7f7c19ce6cd0, flags=...) at kernel/qeventloop.cpp:201
#6  0x00007f7c473a52cf in QThread::exec (this=<value optimized out>) at thread/qthread.cpp:492
#7  0x00007f7c47470c2f in QInotifyFileSystemWatcherEngine::run (this=0x1969500) at io/qfilesystemwatcher_inotify.cpp:248
#8  0x00007f7c473a7d55 in QThreadPrivate::start (arg=0x1969500) at thread/qthread_unix.cpp:320
#9  0x00007f7c3bbc8bc3 in ?? () from /usr/lib/nvidia-current/libGL.so.1
#10 0x00007f7c3f3abd8c in start_thread (arg=0x7f7c19ce7700) at pthread_create.c:304
#11 0x00007f7c4a2d11dd in clone () at ../sysdeps/unix/sysv/linux/x86_64/clone.S:112
#12 0x0000000000000000 in ?? ()

Thread 2 (Thread 0x7f7c17fb3700 (LWP 4696)):
#0  pthread_cond_wait@@GLIBC_2.3.2 () at ../nptl/sysdeps/unix/sysv/linux/x86_64/pthread_cond_wait.S:162
#1  0x00007f7c444d0d82 in ?? () from /usr/lib/libQtScript.so.4
#2  0x00007f7c444d0db9 in ?? () from /usr/lib/libQtScript.so.4
#3  0x00007f7c3bbc8bc3 in ?? () from /usr/lib/nvidia-current/libGL.so.1
#4  0x00007f7c3f3abd8c in start_thread (arg=0x7f7c17fb3700) at pthread_create.c:304
#5  0x00007f7c4a2d11dd in clone () at ../sysdeps/unix/sysv/linux/x86_64/clone.S:112
#6  0x0000000000000000 in ?? ()

Thread 1 (Thread 0x7f7c4a9d77c0 (LWP 4523)):
[KCrash Handler]
#6  QGraphicsLayoutItemPrivate::hasHeightForWidth (this=0xa) at graphicsview/qgraphicslayoutitem.cpp:280
#7  0x00007f7c46e67091 in QGridLayoutItem::hasDynamicConstraint (this=<value optimized out>) at graphicsview/qgridlayoutengine.cpp:576
#8  0x00007f7c46e681b2 in ensureDynamicConstraint (this=0x5197b50) at graphicsview/qgridlayoutengine.cpp:1657
#9  QGridLayoutEngine::ensureDynamicConstraint (this=0x5197b50) at graphicsview/qgridlayoutengine.cpp:1652
#10 0x00007f7c46e68269 in QGridLayoutEngine::hasDynamicConstraint (this=0x5197b50) at graphicsview/qgridlayoutengine.cpp:1677
#11 0x00007f7c46e6c598 in QGridLayoutEngine::sizeHint (this=0x5197b50, styleInfo=..., which=Qt::MaximumSize, constraint=...) at graphicsview/qgridlayoutengine.cpp:1134
#12 0x00007f7c46df64ea in QGraphicsGridLayout::sizeHint (this=<value optimized out>, which=Qt::MaximumSize, constraint=...) at graphicsview/qgraphicsgridlayout.cpp:656
#13 0x00007f7c46e20fb9 in QGraphicsLayoutItemPrivate::effectiveSizeHints (this=0x5197a40, constraint=...) at graphicsview/qgraphicslayoutitem.cpp:169
#14 0x00007f7c46e21871 in effectiveSizeHint (this=<value optimized out>, which=<value optimized out>, constraint=<value optimized out>) at graphicsview/qgraphicslayoutitem.cpp:818
#15 QGraphicsLayoutItem::effectiveSizeHint (this=<value optimized out>, which=<value optimized out>, constraint=<value optimized out>) at graphicsview/qgraphicslayoutitem.cpp:810
#16 0x00007f7c46e5e5b1 in QGraphicsWidget::sizeHint (this=<value optimized out>, which=<value optimized out>, constraint=<value optimized out>) at graphicsview/qgraphicswidget.cpp:729
#17 0x00007f7c46e2108f in QGraphicsLayoutItemPrivate::effectiveSizeHints (this=0x5197950, constraint=...) at graphicsview/qgraphicslayoutitem.cpp:175
#18 0x00007f7c46e21871 in effectiveSizeHint (this=<value optimized out>, which=<value optimized out>, constraint=<value optimized out>) at graphicsview/qgraphicslayoutitem.cpp:818
#19 QGraphicsLayoutItem::effectiveSizeHint (this=<value optimized out>, which=<value optimized out>, constraint=<value optimized out>) at graphicsview/qgraphicslayoutitem.cpp:810
#20 0x00007f7c2d3be845 in SystemTray::TaskArea::adjustHiddentTasksWidget (this=0x538ddf0) at ../../../../../plasma/generic/applets/systemtray/ui/taskarea.cpp:429
#21 0x00007f7c2d3c064e in SystemTray::TaskArea::addWidgetForTask (this=0x538ddf0, task=0x5b62d00) at ../../../../../plasma/generic/applets/systemtray/ui/taskarea.cpp:309
#22 0x00007f7c2d3c0986 in SystemTray::TaskArea::addTask (this=0x538ddf0, task=<value optimized out>) at ../../../../../plasma/generic/applets/systemtray/ui/taskarea.cpp:189
#23 0x00007f7c2d3c0ab4 in SystemTray::TaskArea::qt_metacall (this=0x538ddf0, _c=QMetaObject::InvokeMetaMethod, _id=<value optimized out>, _a=0x7fff10771a70) at ./taskarea.moc:89
#24 0x00007f7c474a16ea in QMetaObject::activate (sender=0x1c9bb70, m=<value optimized out>, local_signal_index=<value optimized out>, argv=0x7fff10771a70) at kernel/qobject.cpp:3278
#25 0x00007f7c2d3a379f in SystemTray::Manager::taskAdded (this=<value optimized out>, _t1=0x5b62d00) at ./manager.moc:99
#26 0x00007f7c2d3a39b5 in SystemTray::Manager::addTask (this=0x1c9bb70, task=0x5b62d00) at ../../../../../plasma/generic/applets/systemtray/core/manager.cpp:87
#27 0x00007f7c2d3a3b04 in SystemTray::Manager::qt_metacall (this=0x1c9bb70, _c=QMetaObject::InvokeMetaMethod, _id=<value optimized out>, _a=0x7fff10771be0) at ./manager.moc:86
#28 0x00007f7c474a16ea in QMetaObject::activate (sender=0x1c9b610, m=<value optimized out>, local_signal_index=<value optimized out>, argv=0x7fff10771be0) at kernel/qobject.cpp:3278
#29 0x00007f7c2d3a3faf in SystemTray::Protocol::taskCreated (this=<value optimized out>, _t1=0x5b62d00) at ./protocol.moc:91
#30 0x00007f7c2d3ab098 in SystemTray::PlasmoidProtocol::addApplet (this=0x1c9b610, appletName=..., id=<value optimized out>, parent=0x5194170) at ../../../../../plasma/generic/applets/systemtray/protocols/plasmoid/plasmoidtaskprotocol.cpp:112
#31 0x00007f7c2d3a35f6 in SystemTray::Manager::addApplet (this=<value optimized out>, appletName=<value optimized out>, parent=<value optimized out>) at ../../../../../plasma/generic/applets/systemtray/core/manager.cpp:110
#32 0x00007f7c2d3b5930 in SystemTray::Applet::checkDefaultApplets (this=0x5194170) at ../../../../../plasma/generic/applets/systemtray/ui/applet.cpp:755
#33 0x00007f7c2d3b694c in SystemTray::Applet::qt_metacall (this=0x5194170, _c=QMetaObject::InvokeMetaMethod, _id=<value optimized out>, _a=0x517d8b0) at ./applet.moc:91
#34 0x00007f7c474a528e in QObject::event (this=0x5194170, e=<value optimized out>) at kernel/qobject.cpp:1217
#35 0x00007f7c46e5ec1b in QGraphicsWidget::event (this=0x5194170, event=0x51a8640) at graphicsview/qgraphicswidget.cpp:1423
#36 0x00007f7c46844154 in notify_helper (this=0x17785c0, receiver=0x5194170, e=0x51a8640) at kernel/qapplication.cpp:4467
#37 QApplicationPrivate::notify_helper (this=0x17785c0, receiver=0x5194170, e=0x51a8640) at kernel/qapplication.cpp:4439
#38 0x00007f7c46848fc1 in QApplication::notify (this=0x174b620, receiver=0x5194170, e=0x51a8640) at kernel/qapplication.cpp:4346
#39 0x00007f7c4813cd56 in KApplication::notify (this=0x174b620, receiver=0x5194170, event=0x51a8640) at ../../kdeui/kernel/kapplication.cpp:311
#40 0x00007f7c4748ea6c in QCoreApplication::notifyInternal (this=0x174b620, receiver=0x5194170, event=0x51a8640) at kernel/qcoreapplication.cpp:731
#41 0x00007f7c47491dff in sendEvent (receiver=0x0, event_type=0, data=0x16a8430) at ../../include/QtCore/../../src/corelib/kernel/qcoreapplication.h:215
#42 QCoreApplicationPrivate::sendPostedEvents (receiver=0x0, event_type=0, data=0x16a8430) at kernel/qcoreapplication.cpp:1372
#43 0x00007f7c474b92e3 in sendPostedEvents (s=<value optimized out>) at ../../include/QtCore/../../src/corelib/kernel/qcoreapplication.h:220
#44 postEventSourceDispatch (s=<value optimized out>) at kernel/qeventdispatcher_glib.cpp:277
#45 0x00007f7c3e8a5cbd in g_main_context_dispatch () from /lib/x86_64-linux-gnu/libglib-2.0.so.0
#46 0x00007f7c3e8a64b8 in ?? () from /lib/x86_64-linux-gnu/libglib-2.0.so.0
#47 0x00007f7c3e8a6689 in g_main_context_iteration () from /lib/x86_64-linux-gnu/libglib-2.0.so.0
#48 0x00007f7c474b9746 in QEventDispatcherGlib::processEvents (this=0x16a9f40, flags=<value optimized out>) at kernel/qeventdispatcher_glib.cpp:422
#49 0x00007f7c468eb72e in QGuiEventDispatcherGlib::processEvents (this=<value optimized out>, flags=<value optimized out>) at kernel/qguieventdispatcher_glib.cpp:204
#50 0x00007f7c4748dc62 in QEventLoop::processEvents (this=<value optimized out>, flags=...) at kernel/qeventloop.cpp:149
#51 0x00007f7c4748de67 in QEventLoop::exec (this=0x7fff10772640, flags=...) at kernel/qeventloop.cpp:201
#52 0x00007f7c4749207b in QCoreApplication::exec () at kernel/qcoreapplication.cpp:1008
#53 0x00007f7c4a5d2093 in kdemain (argc=1, argv=0x7fff10772a28) at ../../../../plasma/desktop/shell/main.cpp:120
#54 0x00007f7c4a209e1f in __libc_start_main (main=0x400640 <main(int, char**)>, argc=1, ubp_av=0x7fff10772a28, init=<value optimized out>, fini=<value optimized out>, rtld_fini=<value optimized out>, stack_end=0x7fff10772a18) at libc-start.c:226
#55 0x0000000000400671 in _start ()

This bug may be a duplicate of or related to bug 277367.

Possible duplicates by query: bug 277367, bug 276144, bug 274819, bug 273082.

Reported using DrKonqi