Qt Version: 5.4.1
Operating System: Linux 3.19.0-9-generic x86_64
Distribution: Ubuntu Vivid Vervet (development branch)


Reproducible: Didn't try

Steps to Reproduce:
1. started my system
2. I'm not sure if this is relevant but i was away for some time and the lock-screen kicked in.
3. when i came back to my system and unlocked it this crash dialog was open



Backtrace is deducted because there where 69 threads
-- Backtrace:
Application: plasmashell (plasmashell), signal: Segmentation fault
Using host libthread_db library "/lib/x86_64-linux-gnu/libthread_db.so.1".
pthread_cond_wait@@GLIBC_2.3.2 () at ../nptl/sysdeps/unix/sysv/linux/x86_64/pthread_cond_wait.S:185
[Current thread is 1 (Thread 0x7fe790b7c800 (LWP 3386))]

Thread 69 (Thread 0x7fe77a12f700 (LWP 3394)):
#0  0x00007fe78b8f00cd in poll () at ../sysdeps/unix/syscall-template.S:81
#1  0x00007fe78e109b72 in  () at /usr/lib/x86_64-linux-gnu/libxcb.so.1
#2  0x00007fe78e10b64f in xcb_wait_for_event () at /usr/lib/x86_64-linux-gnu/libxcb.so.1
#3  0x00007fe77cd5b049 in  () at /usr/lib/x86_64-linux-gnu/qt5/plugins/platforms/libqxcb.so
#4  0x00007fe78bf7bb0e in  () at /usr/lib/x86_64-linux-gnu/libQt5Core.so.5
#5  0x00007fe78b1800a5 in start_thread (arg=0x7fe77a12f700) at pthread_create.c:309
#6  0x00007fe78b8fa57d in clone () at ../sysdeps/unix/sysv/linux/x86_64/clone.S:111

Thread 68 (Thread 0x7fe77347f700 (LWP 3406)):
#0  0x00007fe78b8ebddd in read () at ../sysdeps/unix/syscall-template.S:81
#1  0x00007fe784511f45 in  () at /usr/lib/nvidia-346/tls/libnvidia-tls.so.346.47
#2  0x00007fe787fed2f0 in g_wakeup_acknowledge (__nbytes=16, __buf=0x7fe77347eb90, __fd=<optimized out>) at /usr/include/x86_64-linux-gnu/bits/unistd.h:44
#3  0x00007fe787fed2f0 in g_wakeup_acknowledge (wakeup=0x7fe76c0025a0) at /build/buildd/glib2.0-2.43.92/./glib/gwakeup.c:210
#4  0x00007fe787fa996c in g_main_context_check (context=context@entry=0x7fe7640009b0, max_priority=2147483647, fds=fds@entry=0x7fe764002e70, n_fds=n_fds@entry=1) at /build/buildd/glib2.0-2.43.92/./glib/gmain.c:3600
#5  0x00007fe787fa9e60 in g_main_context_iterate (context=context@entry=0x7fe7640009b0, block=block@entry=1, dispatch=dispatch@entry=1, self=<optimized out>) at /build/buildd/glib2.0-2.43.92/./glib/gmain.c:3805
#6  0x00007fe787fa9fcc in g_main_context_iteration (context=0x7fe7640009b0, may_block=1) at /build/buildd/glib2.0-2.43.92/./glib/gmain.c:3869
#7  0x00007fe78c212bfc in QEventDispatcherGlib::processEvents(QFlags<QEventLoop::ProcessEventsFlag>) () at /usr/lib/x86_64-linux-gnu/libQt5Core.so.5
#8  0x00007fe78c1b73b2 in QEventLoop::exec(QFlags<QEventLoop::ProcessEventsFlag>) () at /usr/lib/x86_64-linux-gnu/libQt5Core.so.5
#9  0x00007fe78bf76b44 in QThread::exec() () at /usr/lib/x86_64-linux-gnu/libQt5Core.so.5
#10 0x00007fe78dfa1f45 in  () at /usr/lib/x86_64-linux-gnu/libQt5Qml.so.5
#11 0x00007fe78bf7bb0e in  () at /usr/lib/x86_64-linux-gnu/libQt5Core.so.5
#12 0x00007fe78b1800a5 in start_thread (arg=0x7fe77347f700) at pthread_create.c:309
#13 0x00007fe78b8fa57d in clone () at ../sysdeps/unix/sysv/linux/x86_64/clone.S:111

Thread 67 (Thread 0x7fe768947700 (LWP 3432)):
#0  0x00007fe790b4b02c in _dl_update_slotinfo (req_modid=1) at dl-tls.c:563
#1  0x00007fe790b3915f in update_get_addr (ti=0x7fe78c415680) at dl-tls.c:753
#2  0x00007fe78bf7aa12 in  () at /usr/lib/x86_64-linux-gnu/libQt5Core.so.5
#3  0x00007fe78c212521 in  () at /usr/lib/x86_64-linux-gnu/libQt5Core.so.5
#4  0x00007fe787fa98c1 in g_main_context_check (context=context@entry=0x7fe760000990, max_priority=2147483647, fds=fds@entry=0x7fe760003070, n_fds=n_fds@entry=1) at /build/buildd/glib2.0-2.43.92/./glib/gmain.c:3649
#5  0x00007fe787fa9e60 in g_main_context_iterate (context=context@entry=0x7fe760000990, block=block@entry=1, dispatch=dispatch@entry=1, self=<optimized out>) at /build/buildd/glib2.0-2.43.92/./glib/gmain.c:3805
#6  0x00007fe787fa9fcc in g_main_context_iteration (context=0x7fe760000990, may_block=1) at /build/buildd/glib2.0-2.43.92/./glib/gmain.c:3869
#7  0x00007fe78c212bfc in QEventDispatcherGlib::processEvents(QFlags<QEventLoop::ProcessEventsFlag>) () at /usr/lib/x86_64-linux-gnu/libQt5Core.so.5
#8  0x00007fe78c1b73b2 in QEventLoop::exec(QFlags<QEventLoop::ProcessEventsFlag>) () at /usr/lib/x86_64-linux-gnu/libQt5Core.so.5
#9  0x00007fe78bf76b44 in QThread::exec() () at /usr/lib/x86_64-linux-gnu/libQt5Core.so.5
#10 0x00007fe78dfa1f45 in  () at /usr/lib/x86_64-linux-gnu/libQt5Qml.so.5
#11 0x00007fe78bf7bb0e in  () at /usr/lib/x86_64-linux-gnu/libQt5Core.so.5
#12 0x00007fe78b1800a5 in start_thread (arg=0x7fe768947700) at pthread_create.c:309
#13 0x00007fe78b8fa57d in clone () at ../sysdeps/unix/sysv/linux/x86_64/clone.S:111
...

Thread 6 (Thread 0x7fe5aeffe700 (LWP 4032)):
#0  0x00007fe78b184250 in pthread_cond_wait@@GLIBC_2.3.2 () at ../nptl/sysdeps/unix/sysv/linux/x86_64/pthread_cond_wait.S:185
#1  0x00007fe78e109db9 in  () at /usr/lib/x86_64-linux-gnu/libxcb.so.1
#2  0x00007fe78e10b3ff in  () at /usr/lib/x86_64-linux-gnu/libxcb.so.1
#3  0x00007fe78e10b512 in xcb_wait_for_reply () at /usr/lib/x86_64-linux-gnu/libxcb.so.1
#4  0x00007fe78e35c69f in _XReply () at /usr/lib/x86_64-linux-gnu/libX11.so.6
#5  0x00007fe7875f70f8 in  () at /usr/lib/nvidia-346/libGL.so.1
#6  0x00007fe7875f89e1 in  () at /usr/lib/nvidia-346/libGL.so.1
#7  0x00007fe77cd82017 in  () at /usr/lib/x86_64-linux-gnu/qt5/plugins/platforms/libqxcb.so
#8  0x00007fe78c54a457 in QOpenGLContext::doneCurrent() () at /usr/lib/x86_64-linux-gnu/libQt5Gui.so.5
#9  0x00007fe7908c05d9 in  () at /usr/lib/x86_64-linux-gnu/libQt5Quick.so.5
#10 0x00007fe7908ba901 in  () at /usr/lib/x86_64-linux-gnu/libQt5Quick.so.5
#11 0x00007fe7908bb338 in  () at /usr/lib/x86_64-linux-gnu/libQt5Quick.so.5
#12 0x00007fe78bf7bb0e in  () at /usr/lib/x86_64-linux-gnu/libQt5Core.so.5
#13 0x00007fe78b1800a5 in start_thread (arg=0x7fe5aeffe700) at pthread_create.c:309
#14 0x00007fe78b8fa57d in clone () at ../sysdeps/unix/sysv/linux/x86_64/clone.S:111

Thread 5 (Thread 0x7fe5ae7fd700 (LWP 4051)):
#0  0x00007fe78b184250 in pthread_cond_wait@@GLIBC_2.3.2 () at ../nptl/sysdeps/unix/sysv/linux/x86_64/pthread_cond_wait.S:185
#1  0x00007fe78bf7cc6b in QWaitCondition::wait(QMutex*, unsigned long) () at /usr/lib/x86_64-linux-gnu/libQt5Core.so.5
#2  0x00007fe7908baf7b in  () at /usr/lib/x86_64-linux-gnu/libQt5Quick.so.5
#3  0x00007fe7908bb370 in  () at /usr/lib/x86_64-linux-gnu/libQt5Quick.so.5
#4  0x00007fe78bf7bb0e in  () at /usr/lib/x86_64-linux-gnu/libQt5Core.so.5
#5  0x00007fe78b1800a5 in start_thread (arg=0x7fe5ae7fd700) at pthread_create.c:309
#6  0x00007fe78b8fa57d in clone () at ../sysdeps/unix/sysv/linux/x86_64/clone.S:111

Thread 4 (Thread 0x7fe5a6567700 (LWP 4132)):
[KCrash Handler]
#6  0x00007fe78bfe13bf in qHash(QString const&, unsigned int) () at /usr/lib/x86_64-linux-gnu/libQt5Core.so.5
#7  0x00007fe78c020fc8 in QtPrivate::QStringList_removeDuplicates(QStringList*) () at /usr/lib/x86_64-linux-gnu/libQt5Core.so.5
#8  0x00007fe5ac830083 in KCupsConnection::updateSubscription() () at /usr/lib/x86_64-linux-gnu/libkcupslib.so
#9  0x00007fe78c1ea999 in QMetaObject::activate(QObject*, int, int, void**) () at /usr/lib/x86_64-linux-gnu/libQt5Core.so.5
#10 0x00007fe78c1f88e8 in QTimer::timerEvent(QTimerEvent*) () at /usr/lib/x86_64-linux-gnu/libQt5Core.so.5
#11 0x00007fe78c1eb6c3 in QObject::event(QEvent*) () at /usr/lib/x86_64-linux-gnu/libQt5Core.so.5
#12 0x00007fe78cacbb2c in QApplicationPrivate::notify_helper(QObject*, QEvent*) () at /usr/lib/x86_64-linux-gnu/libQt5Widgets.so.5
#13 0x00007fe78cad1000 in QApplication::notify(QObject*, QEvent*) () at /usr/lib/x86_64-linux-gnu/libQt5Widgets.so.5
#14 0x00007fe78c1b9bfb in QCoreApplication::notifyInternal(QObject*, QEvent*) () at /usr/lib/x86_64-linux-gnu/libQt5Core.so.5
#15 0x00007fe78c211a75 in QTimerInfoList::activateTimers() () at /usr/lib/x86_64-linux-gnu/libQt5Core.so.5
#16 0x00007fe78c211ef1 in  () at /usr/lib/x86_64-linux-gnu/libQt5Core.so.5
#17 0x00007fe787fa9c3d in g_main_context_dispatch (context=0x7fe5b40033f0) at /build/buildd/glib2.0-2.43.92/./glib/gmain.c:3122
#18 0x00007fe787fa9c3d in g_main_context_dispatch (context=context@entry=0x7fe5b40033f0) at /build/buildd/glib2.0-2.43.92/./glib/gmain.c:3737
#19 0x00007fe787fa9f20 in g_main_context_iterate (context=context@entry=0x7fe5b40033f0, block=block@entry=1, dispatch=dispatch@entry=1, self=<optimized out>) at /build/buildd/glib2.0-2.43.92/./glib/gmain.c:3808
#20 0x00007fe787fa9fcc in g_main_context_iteration (context=0x7fe5b40033f0, may_block=1) at /build/buildd/glib2.0-2.43.92/./glib/gmain.c:3869
#21 0x00007fe78c212be7 in QEventDispatcherGlib::processEvents(QFlags<QEventLoop::ProcessEventsFlag>) () at /usr/lib/x86_64-linux-gnu/libQt5Core.so.5
#22 0x00007fe78c1b73b2 in QEventLoop::exec(QFlags<QEventLoop::ProcessEventsFlag>) () at /usr/lib/x86_64-linux-gnu/libQt5Core.so.5
#23 0x00007fe78bf76b44 in QThread::exec() () at /usr/lib/x86_64-linux-gnu/libQt5Core.so.5
#24 0x00007fe5ac82fcf7 in KCupsConnection::run() () at /usr/lib/x86_64-linux-gnu/libkcupslib.so
#25 0x00007fe78bf7bb0e in  () at /usr/lib/x86_64-linux-gnu/libQt5Core.so.5
#26 0x00007fe78b1800a5 in start_thread (arg=0x7fe5a6567700) at pthread_create.c:309
#27 0x00007fe78b8fa57d in clone () at ../sysdeps/unix/sysv/linux/x86_64/clone.S:111

Thread 3 (Thread 0x7fe5a5747700 (LWP 4149)):
#0  0x00007fe787fee7a4 in g_mutex_unlock (mutex=0x7fe5b024e590) at /build/buildd/glib2.0-2.43.92/./glib/gthread-posix.c:1354
#1  0x00007fe787fa9852 in g_main_context_check (context=context@entry=0x7fe5b024e590, max_priority=2147483647, fds=fds@entry=0x7fe5b00082a0, n_fds=n_fds@entry=1) at /build/buildd/glib2.0-2.43.92/./glib/gmain.c:3716
#2  0x00007fe787fa9e60 in g_main_context_iterate (context=context@entry=0x7fe5b024e590, block=block@entry=1, dispatch=dispatch@entry=1, self=<optimized out>) at /build/buildd/glib2.0-2.43.92/./glib/gmain.c:3805
#3  0x00007fe787fa9fcc in g_main_context_iteration (context=0x7fe5b024e590, may_block=1) at /build/buildd/glib2.0-2.43.92/./glib/gmain.c:3869
#4  0x00007fe78c212bfc in QEventDispatcherGlib::processEvents(QFlags<QEventLoop::ProcessEventsFlag>) () at /usr/lib/x86_64-linux-gnu/libQt5Core.so.5
#5  0x00007fe78c1b73b2 in QEventLoop::exec(QFlags<QEventLoop::ProcessEventsFlag>) () at /usr/lib/x86_64-linux-gnu/libQt5Core.so.5
#6  0x00007fe78bf76b44 in QThread::exec() () at /usr/lib/x86_64-linux-gnu/libQt5Core.so.5
#7  0x00007fe78dfa1f45 in  () at /usr/lib/x86_64-linux-gnu/libQt5Qml.so.5
#8  0x00007fe78bf7bb0e in  () at /usr/lib/x86_64-linux-gnu/libQt5Core.so.5
#9  0x00007fe78b1800a5 in start_thread (arg=0x7fe5a5747700) at pthread_create.c:309
#10 0x00007fe78b8fa57d in clone () at ../sysdeps/unix/sysv/linux/x86_64/clone.S:111

Thread 2 (Thread 0x7fe5a4746700 (LWP 4151)):
#0  0x00007fe78c211f51 in  () at /usr/lib/x86_64-linux-gnu/libQt5Core.so.5
#1  0x00007fe787fa93fd in g_main_context_prepare (context=context@entry=0x7fe5b80031f0, priority=priority@entry=0x7fe5a4745c60) at /build/buildd/glib2.0-2.43.92/./glib/gmain.c:3410
#2  0x00007fe787fa9de8 in g_main_context_iterate (context=context@entry=0x7fe5b80031f0, block=block@entry=1, dispatch=dispatch@entry=1, self=<optimized out>) at /build/buildd/glib2.0-2.43.92/./glib/gmain.c:3788
#3  0x00007fe787fa9fcc in g_main_context_iteration (context=0x7fe5b80031f0, may_block=1) at /build/buildd/glib2.0-2.43.92/./glib/gmain.c:3869
#4  0x00007fe78c212bfc in QEventDispatcherGlib::processEvents(QFlags<QEventLoop::ProcessEventsFlag>) () at /usr/lib/x86_64-linux-gnu/libQt5Core.so.5
#5  0x00007fe78c1b73b2 in QEventLoop::exec(QFlags<QEventLoop::ProcessEventsFlag>) () at /usr/lib/x86_64-linux-gnu/libQt5Core.so.5
#6  0x00007fe78bf76b44 in QThread::exec() () at /usr/lib/x86_64-linux-gnu/libQt5Core.so.5
#7  0x00007fe78dfa1f45 in  () at /usr/lib/x86_64-linux-gnu/libQt5Qml.so.5
#8  0x00007fe78bf7bb0e in  () at /usr/lib/x86_64-linux-gnu/libQt5Core.so.5
#9  0x00007fe78b1800a5 in start_thread (arg=0x7fe5a4746700) at pthread_create.c:309
#10 0x00007fe78b8fa57d in clone () at ../sysdeps/unix/sysv/linux/x86_64/clone.S:111

Thread 1 (Thread 0x7fe790b7c800 (LWP 3386)):
#0  0x00007fe78b184250 in pthread_cond_wait@@GLIBC_2.3.2 () at ../nptl/sysdeps/unix/sysv/linux/x86_64/pthread_cond_wait.S:185
#1  0x00007fe78bf7cc6b in QWaitCondition::wait(QMutex*, unsigned long) () at /usr/lib/x86_64-linux-gnu/libQt5Core.so.5
#2  0x00007fe7908be055 in  () at /usr/lib/x86_64-linux-gnu/libQt5Quick.so.5
#3  0x00007fe7908c02f3 in  () at /usr/lib/x86_64-linux-gnu/libQt5Quick.so.5
#4  0x00007fe78c5147b5 in QWindow::event(QEvent*) () at /usr/lib/x86_64-linux-gnu/libQt5Gui.so.5
#5  0x00007fe7908f1da3 in QQuickWindow::event(QEvent*) () at /usr/lib/x86_64-linux-gnu/libQt5Quick.so.5
#6  0x00000000004420c3 in PanelView::event(QEvent*) ()
#7  0x00007fe78cacbb2c in QApplicationPrivate::notify_helper(QObject*, QEvent*) () at /usr/lib/x86_64-linux-gnu/libQt5Widgets.so.5
#8  0x00007fe78cad1000 in QApplication::notify(QObject*, QEvent*) () at /usr/lib/x86_64-linux-gnu/libQt5Widgets.so.5
#9  0x00007fe78c1b9bfb in QCoreApplication::notifyInternal(QObject*, QEvent*) () at /usr/lib/x86_64-linux-gnu/libQt5Core.so.5
#10 0x00007fe78c50ce86 in QGuiApplicationPrivate::processExposeEvent(QWindowSystemInterfacePrivate::ExposeEvent*) () at /usr/lib/x86_64-linux-gnu/libQt5Gui.so.5
#11 0x00007fe78c50dbbd in QGuiApplicationPrivate::processWindowSystemEvent(QWindowSystemInterfacePrivate::WindowSystemEvent*) () at /usr/lib/x86_64-linux-gnu/libQt5Gui.so.5
#12 0x00007fe78c4f234f in QWindowSystemInterface::sendWindowSystemEvents(QFlags<QEventLoop::ProcessEventsFlag>) () at /usr/lib/x86_64-linux-gnu/libQt5Gui.so.5
#13 0x00007fe77cd854f0 in  () at /usr/lib/x86_64-linux-gnu/qt5/plugins/platforms/libqxcb.so
#14 0x00007fe787fa9c3d in g_main_context_dispatch (context=0x7fe774001710) at /build/buildd/glib2.0-2.43.92/./glib/gmain.c:3122
#15 0x00007fe787fa9c3d in g_main_context_dispatch (context=context@entry=0x7fe774001710) at /build/buildd/glib2.0-2.43.92/./glib/gmain.c:3737
#16 0x00007fe787fa9f20 in g_main_context_iterate (context=context@entry=0x7fe774001710, block=block@entry=1, dispatch=dispatch@entry=1, self=<optimized out>) at /build/buildd/glib2.0-2.43.92/./glib/gmain.c:3808
#17 0x00007fe787fa9fcc in g_main_context_iteration (context=0x7fe774001710, may_block=1) at /build/buildd/glib2.0-2.43.92/./glib/gmain.c:3869
#18 0x00007fe78c212be7 in QEventDispatcherGlib::processEvents(QFlags<QEventLoop::ProcessEventsFlag>) () at /usr/lib/x86_64-linux-gnu/libQt5Core.so.5
#19 0x00007fe78c1b73b2 in QEventLoop::exec(QFlags<QEventLoop::ProcessEventsFlag>) () at /usr/lib/x86_64-linux-gnu/libQt5Core.so.5
#20 0x00007fe78c1beffc in QCoreApplication::exec() () at /usr/lib/x86_64-linux-gnu/libQt5Core.so.5
#21 0x000000000042fd0f in main ()