Application: plasmashell (5.12.6)

Qt Version: 5.9.6
Frameworks Version: 5.48.0
Operating System: Linux 4.18.13-100.fc27.x86_64 x86_64
Distribution: "Fedora release 27 (Twenty Seven)"

-- Information about the crash:
- What I was doing when the application crashed:

I logged into a new session and plasma session never loaded the taskbar. Then it crashed. All attempts to restart plasmashell behave the same way. That is:
1. Desktop loads with icons
2. Taskbar never loads
3. Everything goes black (Plasmashell segfaults)

The crash can be reproduced every time.

-- Backtrace:
Application: Plasma (plasmashell), signal: Segmentation fault
Using host libthread_db library "/lib64/libthread_db.so.1".
[Current thread is 1 (Thread 0x7f0d476b4940 (LWP 30247))]

Thread 8 (Thread 0x7f0c6e263700 (LWP 30260)):
#0  0x00007f0d3edde8b8 in read () at /lib64/libc.so.6
#1  0x00007f0d372ec160 in g_wakeup_acknowledge () at /lib64/libglib-2.0.so.0
#2  0x00007f0d372a79c8 in g_main_context_check () at /lib64/libglib-2.0.so.0
#3  0x00007f0d372a7e60 in g_main_context_iterate.isra () at /lib64/libglib-2.0.so.0
#4  0x00007f0d372a7fcc in g_main_context_iteration () at /lib64/libglib-2.0.so.0
#5  0x00007f0d3fc39d3b in QEventDispatcherGlib::processEvents(QFlags<QEventLoop::ProcessEventsFlag>) () at /lib64/libQt5Core.so.5
#6  0x00007f0d3fbe7a3a in QEventLoop::exec(QFlags<QEventLoop::ProcessEventsFlag>) () at /lib64/libQt5Core.so.5
#7  0x00007f0d3fa38a1a in QThread::exec() () at /lib64/libQt5Core.so.5
#8  0x00007f0c70bca5a7 in KCupsConnection::run() () at /lib64/libkcupslib.so
#9  0x00007f0d3fa3cf32 in QThreadPrivate::start(void*) () at /lib64/libQt5Core.so.5
#10 0x00007f0d3e13f50b in start_thread () at /lib64/libpthread.so.0
#11 0x00007f0d3eded38f in clone () at /lib64/libc.so.6

Thread 7 (Thread 0x7f0c85765700 (LWP 30253)):
#0  0x00007f0d3ede2ddb in poll () at /lib64/libc.so.6
#1  0x00007f0d372a7eb9 in g_main_context_iterate.isra () at /lib64/libglib-2.0.so.0
#2  0x00007f0d372a7fcc in g_main_context_iteration () at /lib64/libglib-2.0.so.0
#3  0x00007f0d3fc39d3b in QEventDispatcherGlib::processEvents(QFlags<QEventLoop::ProcessEventsFlag>) () at /lib64/libQt5Core.so.5
#4  0x00007f0d3fbe7a3a in QEventLoop::exec(QFlags<QEventLoop::ProcessEventsFlag>) () at /lib64/libQt5Core.so.5
#5  0x00007f0d3fa38a1a in QThread::exec() () at /lib64/libQt5Core.so.5
#6  0x00007f0d44a59576 in QQuickPixmapReader::run() () at /lib64/libQt5Quick.so.5
#7  0x00007f0d3fa3cf32 in QThreadPrivate::start(void*) () at /lib64/libQt5Core.so.5
#8  0x00007f0d3e13f50b in start_thread () at /lib64/libpthread.so.0
#9  0x00007f0d3eded38f in clone () at /lib64/libc.so.6

Thread 6 (Thread 0x7f0d19358700 (LWP 30252)):
#0  0x00007f0d3e14582d in pthread_cond_wait@@GLIBC_2.3.2 () at /lib64/libpthread.so.0
#1  0x00007f0d46d8c604 in QTWTF::TCMalloc_PageHeap::scavengerThread() () at /lib64/libQt5Script.so.5
#2  0x00007f0d46d8c649 in  () at /lib64/libQt5Script.so.5
#3  0x00007f0d3e13f50b in start_thread () at /lib64/libpthread.so.0
#4  0x00007f0d3eded38f in clone () at /lib64/libc.so.6

Thread 5 (Thread 0x7f0d1b3b8700 (LWP 30251)):
#0  0x00007f0d3ede2ddb in poll () at /lib64/libc.so.6
#1  0x00007f0d372a7eb9 in g_main_context_iterate.isra () at /lib64/libglib-2.0.so.0
#2  0x00007f0d372a7fcc in g_main_context_iteration () at /lib64/libglib-2.0.so.0
#3  0x00007f0d3fc39d3b in QEventDispatcherGlib::processEvents(QFlags<QEventLoop::ProcessEventsFlag>) () at /lib64/libQt5Core.so.5
#4  0x00007f0d3fbe7a3a in QEventLoop::exec(QFlags<QEventLoop::ProcessEventsFlag>) () at /lib64/libQt5Core.so.5
#5  0x00007f0d3fa38a1a in QThread::exec() () at /lib64/libQt5Core.so.5
#6  0x00007f0d43eba565 in QQmlThreadPrivate::run() () at /lib64/libQt5Qml.so.5
#7  0x00007f0d3fa3cf32 in QThreadPrivate::start(void*) () at /lib64/libQt5Core.so.5
#8  0x00007f0d3e13f50b in start_thread () at /lib64/libpthread.so.0
#9  0x00007f0d3eded38f in clone () at /lib64/libc.so.6

Thread 4 (Thread 0x7f0d219cb700 (LWP 30250)):
#0  0x00007f0d372ed499 in g_mutex_lock () at /lib64/libglib-2.0.so.0
#1  0x00007f0d372a78f6 in g_main_context_check () at /lib64/libglib-2.0.so.0
#2  0x00007f0d372a7e60 in g_main_context_iterate.isra () at /lib64/libglib-2.0.so.0
#3  0x00007f0d372a7fcc in g_main_context_iteration () at /lib64/libglib-2.0.so.0
#4  0x00007f0d3fc39d3b in QEventDispatcherGlib::processEvents(QFlags<QEventLoop::ProcessEventsFlag>) () at /lib64/libQt5Core.so.5
#5  0x00007f0d3fbe7a3a in QEventLoop::exec(QFlags<QEventLoop::ProcessEventsFlag>) () at /lib64/libQt5Core.so.5
#6  0x00007f0d3fa38a1a in QThread::exec() () at /lib64/libQt5Core.so.5
#7  0x00007f0d43eba565 in QQmlThreadPrivate::run() () at /lib64/libQt5Qml.so.5
#8  0x00007f0d3fa3cf32 in QThreadPrivate::start(void*) () at /lib64/libQt5Core.so.5
#9  0x00007f0d3e13f50b in start_thread () at /lib64/libpthread.so.0
#10 0x00007f0d3eded38f in clone () at /lib64/libc.so.6

Thread 3 (Thread 0x7f0d23410700 (LWP 30249)):
#0  0x00007f0d372a7374 in g_main_context_prepare () at /lib64/libglib-2.0.so.0
#1  0x00007f0d372a7deb in g_main_context_iterate.isra () at /lib64/libglib-2.0.so.0
#2  0x00007f0d372a7fcc in g_main_context_iteration () at /lib64/libglib-2.0.so.0
#3  0x00007f0d3fc39d3b in QEventDispatcherGlib::processEvents(QFlags<QEventLoop::ProcessEventsFlag>) () at /lib64/libQt5Core.so.5
#4  0x00007f0d3fbe7a3a in QEventLoop::exec(QFlags<QEventLoop::ProcessEventsFlag>) () at /lib64/libQt5Core.so.5
#5  0x00007f0d3fa38a1a in QThread::exec() () at /lib64/libQt5Core.so.5
#6  0x00007f0d40051449 in QDBusConnectionManager::run() () at /lib64/libQt5DBus.so.5
#7  0x00007f0d3fa3cf32 in QThreadPrivate::start(void*) () at /lib64/libQt5Core.so.5
#8  0x00007f0d3e13f50b in start_thread () at /lib64/libpthread.so.0
#9  0x00007f0d3eded38f in clone () at /lib64/libc.so.6

Thread 2 (Thread 0x7f0d29604700 (LWP 30248)):
#0  0x00007f0d3ede2ddb in poll () at /lib64/libc.so.6
#1  0x00007f0d45669fe7 in _xcb_conn_wait () at /lib64/libxcb.so.1
#2  0x00007f0d4566bdda in xcb_wait_for_event () at /lib64/libxcb.so.1
#3  0x00007f0d2b352cd9 in QXcbEventReader::run() () at /lib64/libQt5XcbQpa.so.5
#4  0x00007f0d3fa3cf32 in QThreadPrivate::start(void*) () at /lib64/libQt5Core.so.5
#5  0x00007f0d3e13f50b in start_thread () at /lib64/libpthread.so.0
#6  0x00007f0d3eded38f in clone () at /lib64/libc.so.6

Thread 1 (Thread 0x7f0d476b4940 (LWP 30247)):
[KCrash Handler]
#6  0x00007f0c70be73c6 in JobModel::updateJob(int, KCupsJob const&) () at /lib64/libkcupslib.so
#7  0x00007f0c70bebd0f in JobModel::getJobFinished() () at /lib64/libkcupslib.so
#8  0x00007f0c70bf0225 in JobModel::qt_static_metacall(QObject*, QMetaObject::Call, int, void**) [clone .part.6] () at /lib64/libkcupslib.so
#9  0x00007f0d3fc1235a in QObject::event(QEvent*) () at /lib64/libQt5Core.so.5
#10 0x00007f0d40d1b92c in QApplicationPrivate::notify_helper(QObject*, QEvent*) () at /lib64/libQt5Widgets.so.5
#11 0x00007f0d40d23174 in QApplication::notify(QObject*, QEvent*) () at /lib64/libQt5Widgets.so.5
#12 0x00007f0d3fbe8cd7 in QCoreApplication::notifyInternal2(QObject*, QEvent*) () at /lib64/libQt5Core.so.5
#13 0x00007f0d3fbeb45b in QCoreApplicationPrivate::sendPostedEvents(QObject*, int, QThreadData*) () at /lib64/libQt5Core.so.5
#14 0x00007f0d3fc39f33 in postEventSourceDispatch(_GSource*, int (*)(void*), void*) () at /lib64/libQt5Core.so.5
#15 0x00007f0d372a7b97 in g_main_context_dispatch () at /lib64/libglib-2.0.so.0
#16 0x00007f0d372a7f40 in g_main_context_iterate.isra () at /lib64/libglib-2.0.so.0
#17 0x00007f0d372a7fcc in g_main_context_iteration () at /lib64/libglib-2.0.so.0
#18 0x00007f0d3fc39d1f in QEventDispatcherGlib::processEvents(QFlags<QEventLoop::ProcessEventsFlag>) () at /lib64/libQt5Core.so.5
#19 0x00007f0d3fbe7a3a in QEventLoop::exec(QFlags<QEventLoop::ProcessEventsFlag>) () at /lib64/libQt5Core.so.5
#20 0x00007f0d3fbf0194 in QCoreApplication::exec() () at /lib64/libQt5Core.so.5
#21 0x00005578a9227d6a in main ()

Possible duplicates by query: bug 399400.

Reported using DrKonqi