Bug 302640

Application: plasma-desktop (0.4)
KDE Platform Version: 4.8.3 (4.8.3)
Qt Version: 4.8.1
Operating System: Linux 3.2.0-25-generic x86_64
Distribution: Ubuntu 12.04 LTS

-- Information about the crash:
- What I was doing when the application crashed:
Right-clicked a task in Task Manager; expected the task menu to come up, got a crash instead. This sometimes happens to me under heavy load (around 8 IIRC; this time, another app was doing heavy i/o at the same time, not sure if this might be related).

plasma-desktop came back up after few tens of seconds, seems to be holding up okay since then.
- Custom settings of the application (not sure if any of this is relevant):
two "default" bottom panels, one on each monitor (LVDS and HDMI)
two virtual desktops
Task manager configured to display only tasks from current desktop and monitor
no custom activities or widgets, no shared widgets
three different network connections, configured on startup through nm-cli
on login, my script does an `akonadictl stop`

Using Ubuntu 12.04 upgraded from 11.10; bug manifested similarly with previous kernel versions, also in previous release.

The crash can be reproduced some of the time.

-- Backtrace:
Application: Shell plochy Plasma (plasma-desktop), signal: Segmentation fault
Using host libthread_db library "/lib/x86_64-linux-gnu/libthread_db.so.1".
[Current thread is 1 (Thread 0x7fa6c05f7780 (LWP 2748))]

Thread 4 (Thread 0x7fa69b82c700 (LWP 2848)):
#0  timerSourcePrepareHelper (src=0x7fa694002800, timeout=0x7fa69b82bc6c) at kernel/qeventdispatcher_glib.cpp:134
#1  0x00007fa6bd0a6a25 in timerSourcePrepare (source=<optimized out>, timeout=<optimized out>) at kernel/qeventdispatcher_glib.cpp:169
#2  0x00007fa6b4083846 in g_main_context_prepare () from /lib/x86_64-linux-gnu/libglib-2.0.so.0
#3  0x00007fa6b4083f5b in ?? () from /lib/x86_64-linux-gnu/libglib-2.0.so.0
#4  0x00007fa6b4084164 in g_main_context_iteration () from /lib/x86_64-linux-gnu/libglib-2.0.so.0
#5  0x00007fa6bd0a7426 in QEventDispatcherGlib::processEvents (this=0x7fa6940008c0, flags=...) at kernel/qeventdispatcher_glib.cpp:426
#6  0x00007fa6bd076c82 in QEventLoop::processEvents (this=<optimized out>, flags=...) at kernel/qeventloop.cpp:149
#7  0x00007fa6bd076ed7 in QEventLoop::exec (this=0x7fa69b82bdd0, flags=...) at kernel/qeventloop.cpp:204
#8  0x00007fa6bcf75fa7 in QThread::exec (this=<optimized out>) at thread/qthread.cpp:501
#9  0x00007fa6bd0569ff in QInotifyFileSystemWatcherEngine::run (this=0x2f4c6a0) at io/qfilesystemwatcher_inotify.cpp:248
#10 0x00007fa6bcf78fcb in QThreadPrivate::start (arg=0x2f4c6a0) at thread/qthread_unix.cpp:298
#11 0x00007fa6b4988e9a in start_thread (arg=0x7fa69b82c700) at pthread_create.c:308
#12 0x00007fa6bfed64bd in clone () at ../sysdeps/unix/sysv/linux/x86_64/clone.S:112
#13 0x0000000000000000 in ?? ()

Thread 3 (Thread 0x7fa69a252700 (LWP 2849)):
#0  0x00007fa6b433514e in __GI_clock_gettime (clock_id=1, tp=0x7fa69a251b80) at ../sysdeps/unix/clock_gettime.c:116
#1  0x00007fa6bcfcfbb4 in do_gettime (frac=0x7fa69a251b98, sec=0x7fa69a251b90) at tools/qelapsedtimer_unix.cpp:123
#2  qt_gettime () at tools/qelapsedtimer_unix.cpp:140
#3  0x00007fa6bd0a7b8d in QTimerInfoList::updateCurrentTime (this=0x7fa68c002660) at kernel/qeventdispatcher_unix.cpp:343
#4  0x00007fa6bd0a7ec3 in QTimerInfoList::timerWait (this=0x7fa68c002660, tm=...) at kernel/qeventdispatcher_unix.cpp:450
#5  0x00007fa6bd0a697c in timerSourcePrepareHelper (src=<optimized out>, timeout=0x7fa69a251c6c) at kernel/qeventdispatcher_glib.cpp:136
#6  0x00007fa6bd0a6a25 in timerSourcePrepare (source=<optimized out>, timeout=<optimized out>) at kernel/qeventdispatcher_glib.cpp:169
#7  0x00007fa6b4083846 in g_main_context_prepare () from /lib/x86_64-linux-gnu/libglib-2.0.so.0
#8  0x00007fa6b4083f5b in ?? () from /lib/x86_64-linux-gnu/libglib-2.0.so.0
#9  0x00007fa6b4084164 in g_main_context_iteration () from /lib/x86_64-linux-gnu/libglib-2.0.so.0
#10 0x00007fa6bd0a7426 in QEventDispatcherGlib::processEvents (this=0x7fa68c0008c0, flags=...) at kernel/qeventdispatcher_glib.cpp:426
#11 0x00007fa6bd076c82 in QEventLoop::processEvents (this=<optimized out>, flags=...) at kernel/qeventloop.cpp:149
#12 0x00007fa6bd076ed7 in QEventLoop::exec (this=0x7fa69a251dd0, flags=...) at kernel/qeventloop.cpp:204
#13 0x00007fa6bcf75fa7 in QThread::exec (this=<optimized out>) at thread/qthread.cpp:501
#14 0x00007fa6bd0569ff in QInotifyFileSystemWatcherEngine::run (this=0x2757640) at io/qfilesystemwatcher_inotify.cpp:248
#15 0x00007fa6bcf78fcb in QThreadPrivate::start (arg=0x2757640) at thread/qthread_unix.cpp:298
#16 0x00007fa6b4988e9a in start_thread (arg=0x7fa69a252700) at pthread_create.c:308
#17 0x00007fa6bfed64bd in clone () at ../sysdeps/unix/sysv/linux/x86_64/clone.S:112
#18 0x0000000000000000 in ?? ()

Thread 2 (Thread 0x7fa692b7a700 (LWP 2852)):
#0  pthread_cond_wait@@GLIBC_2.3.2 () at ../nptl/sysdeps/unix/sysv/linux/x86_64/pthread_cond_wait.S:162
#1  0x00007fa6b9e5b222 in ?? () from /usr/lib/x86_64-linux-gnu/libQtScript.so.4
#2  0x00007fa6b9e5b259 in ?? () from /usr/lib/x86_64-linux-gnu/libQtScript.so.4
#3  0x00007fa6b4988e9a in start_thread (arg=0x7fa692b7a700) at pthread_create.c:308
#4  0x00007fa6bfed64bd in clone () at ../sysdeps/unix/sysv/linux/x86_64/clone.S:112
#5  0x0000000000000000 in ?? ()

Thread 1 (Thread 0x7fa6c05f7780 (LWP 2748)):
[KCrash Handler]
#6  QString (other=<error reading variable: Cannot access memory at address 0x10>, this=0x7fff168f0f20) at /usr/include/qt4/QtCore/qstring.h:725
#7  KSycocaEntry::entryPath (this=0x0) at ../../kdecore/sycoca/ksycocaentry.cpp:107
#8  0x00007fa6a44c1943 in TaskManager::GroupManagerPrivate::launcherIndex (this=<optimized out>, url=...) at ../../../libs/taskmanager/groupmanager.cpp:1140
#9  0x00007fa6a44c1cbd in TaskManager::GroupManager::launcherExists (this=<optimized out>, url=...) at ../../../libs/taskmanager/groupmanager.cpp:829
#10 0x00007fa6a44d6adc in ToggleLauncherActionImpl (this=0x1030a250, parent=<optimized out>, item=<optimized out>, strategy=<optimized out>) at ../../../libs/taskmanager/taskactions.cpp:411
#11 TaskManager::ToggleLauncherActionImpl::ToggleLauncherActionImpl (this=0x1030a250, parent=<optimized out>, item=<optimized out>, strategy=0x80700f0) at ../../../libs/taskmanager/taskactions.cpp:374
#12 0x00007fa6a44d7af0 in TaskManager::BasicMenu::BasicMenu (this=0x7fff168f1120, parent=<optimized out>, item=0xd11cdf0, strategy=0x80700f0, visualizationActions=..., appActions=...) at ../../../libs/taskmanager/taskactions.cpp:569
#13 0x00007fa6a3e5e954 in WindowTaskItem::contextMenuEvent (this=0xd0c1ff0, e=<optimized out>) at ../../../../../plasma/desktop/applets/tasks/windowtaskitem.cpp:331
#14 0x00007fa6bc9e0425 in QGraphicsItem::sceneEvent (this=0xd0c2000, event=0x7fff168f1940) at graphicsview/qgraphicsitem.cpp:6711
#15 0x00007fa6bca0877e in QGraphicsScene::contextMenuEvent (this=<optimized out>, contextMenuEvent=0x7fff168f1940) at graphicsview/qgraphicsscene.cpp:3617
#16 0x00007fa6bca17764 in QGraphicsScene::event (this=0x21f0c10, event=0x7fff168f1940) at graphicsview/qgraphicsscene.cpp:3412
#17 0x00007fa6bc3fa894 in notify_helper (e=0x7fff168f1940, receiver=0x21f0c10, this=0x20e9be0) at kernel/qapplication.cpp:4559
#18 QApplicationPrivate::notify_helper (this=0x20e9be0, receiver=0x21f0c10, e=0x7fff168f1940) at kernel/qapplication.cpp:4531
#19 0x00007fa6bc3ff713 in QApplication::notify (this=0x20d33a0, receiver=0x21f0c10, e=0x7fff168f1940) at kernel/qapplication.cpp:4420
#20 0x00007fa6bdd55bb6 in KApplication::notify (this=0x20d33a0, receiver=0x21f0c10, event=0x7fff168f1940) at ../../kdeui/kernel/kapplication.cpp:311
#21 0x00007fa6bd077e9c in QCoreApplication::notifyInternal (this=0x20d33a0, receiver=0x21f0c10, event=0x7fff168f1940) at kernel/qcoreapplication.cpp:876
#22 0x00007fa6bca2d3ab in sendEvent (event=0x7fff168f1940, receiver=<optimized out>) at ../../include/QtCore/../../src/corelib/kernel/qcoreapplication.h:231
#23 QGraphicsView::contextMenuEvent (this=0x9aea660, event=0x7fff168f2230) at graphicsview/qgraphicsview.cpp:2892
#24 0x00007fa6bc44ae94 in QWidget::event (this=0x9aea660, event=0x7fff168f2230) at kernel/qwidget.cpp:8529
#25 0x00007fa6bc80b3b6 in QFrame::event (this=0x9aea660, e=0x7fff168f2230) at widgets/qframe.cpp:557
#26 0x00007fa6bca35b2b in QGraphicsView::viewportEvent (this=0x9aea660, event=0x7fff168f2230) at graphicsview/qgraphicsview.cpp:2866
#27 0x00007fa6bd078028 in QCoreApplicationPrivate::sendThroughObjectEventFilters (this=<optimized out>, receiver=0x9aff740, event=0x7fff168f2230) at kernel/qcoreapplication.cpp:986
#28 0x00007fa6bc3fa85f in notify_helper (e=0x7fff168f2230, receiver=0x9aff740, this=0x20e9be0) at kernel/qapplication.cpp:4555
#29 QApplicationPrivate::notify_helper (this=0x20e9be0, receiver=0x9aff740, e=0x7fff168f2230) at kernel/qapplication.cpp:4531
#30 0x00007fa6bc3ffbcd in QApplication::notify (this=<optimized out>, receiver=0x9aff740, e=0x7fff168f2230) at kernel/qapplication.cpp:4181
#31 0x00007fa6bdd55bb6 in KApplication::notify (this=0x20d33a0, receiver=0x9aff740, event=0x7fff168f2230) at ../../kdeui/kernel/kapplication.cpp:311
#32 0x00007fa6bd077e9c in QCoreApplication::notifyInternal (this=0x20d33a0, receiver=0x9aff740, event=0x7fff168f2230) at kernel/qcoreapplication.cpp:876
#33 0x00007fa6bc47ac58 in sendSpontaneousEvent (event=0x7fff168f2230, receiver=0x9aff740) at ../../include/QtCore/../../src/corelib/kernel/qcoreapplication.h:234
#34 QETWidget::translateMouseEvent (this=<optimized out>, event=<optimized out>) at kernel/qapplication_x11.cpp:4622
#35 0x00007fa6bc479bae in QApplication::x11ProcessEvent (this=0x20d33a0, event=0x7fff168f2ad0) at kernel/qapplication_x11.cpp:3732
#36 0x00007fa6bc4a30d2 in x11EventSourceDispatch (s=0x20f0c70, callback=0, user_data=0x0) at kernel/qguieventdispatcher_glib.cpp:146
#37 0x00007fa6b4083d53 in g_main_context_dispatch () from /lib/x86_64-linux-gnu/libglib-2.0.so.0
#38 0x00007fa6b40840a0 in ?? () from /lib/x86_64-linux-gnu/libglib-2.0.so.0
#39 0x00007fa6b4084164 in g_main_context_iteration () from /lib/x86_64-linux-gnu/libglib-2.0.so.0
#40 0x00007fa6bd0a73bf in QEventDispatcherGlib::processEvents (this=0x2067ad0, flags=...) at kernel/qeventdispatcher_glib.cpp:424
#41 0x00007fa6bc4a2d5e in QGuiEventDispatcherGlib::processEvents (this=<optimized out>, flags=...) at kernel/qguieventdispatcher_glib.cpp:204
#42 0x00007fa6bd076c82 in QEventLoop::processEvents (this=<optimized out>, flags=...) at kernel/qeventloop.cpp:149
#43 0x00007fa6bd076ed7 in QEventLoop::exec (this=0x7fff168f2e70, flags=...) at kernel/qeventloop.cpp:204
#44 0x00007fa6bd07bf67 in QCoreApplication::exec () at kernel/qcoreapplication.cpp:1148
#45 0x00007fa6c01e2a13 in kdemain (argc=1, argv=0x7fff168f3258) at ../../../../plasma/desktop/shell/main.cpp:120
#46 0x00007fa6bfe0576d in __libc_start_main (main=0x400640 <main(int, char**)>, argc=1, ubp_av=0x7fff168f3258, init=<optimized out>, fini=<optimized out>, rtld_fini=<optimized out>, stack_end=0x7fff168f3248) at libc-start.c:226
#47 0x0000000000400671 in _start ()

Reported using DrKonqi