Application: plasmashell (5.5.5)
 (Compiled from sources)
Qt Version: 5.5.1
Operating System: Linux 4.4.0-21-generic x86_64
Distribution: Ubuntu 16.04 LTS

-- Information about the crash:
I was using Firefox aurora once, Konsole the other time.
Plasma would crash, the taskbar would isappear and then reappear after the crash message, did not have to restart the application.

The crash can be reproduced sometimes.

-- Backtrace:
Application: Plasma (plasmashell), signal: Segmentation fault
Using host libthread_db library "/lib/x86_64-linux-gnu/libthread_db.so.1".
[Current thread is 1 (Thread 0x7f63fd2d28c0 (LWP 4110))]

Thread 12 (Thread 0x7f63e85f4700 (LWP 4112)):
#0  0x00007f63f79f5e8d in poll () at ../sysdeps/unix/syscall-template.S:84
#1  0x00007f63fbabac62 in poll (__timeout=-1, __nfds=1, __fds=0x7f63e85f3c00) at /usr/include/x86_64-linux-gnu/bits/poll2.h:46
#2  _xcb_conn_wait (c=c@entry=0x909170, cond=cond@entry=0x9091b0, vector=vector@entry=0x0, count=count@entry=0x0) at ../../src/xcb_conn.c:459
#3  0x00007f63fbabc8d7 in xcb_wait_for_event (c=0x909170) at ../../src/xcb_in.c:693
#4  0x00007f63ea742629 in QXcbEventReader::run (this=0x9176c0) at qxcbconnection.cpp:1253
#5  0x00007f63f80eb84e in QThreadPrivate::start (arg=0x9176c0) at thread/qthread_unix.cpp:331
#6  0x00007f63f71d86fa in start_thread (arg=0x7f63e85f4700) at pthread_create.c:333
#7  0x00007f63f7a01b5d in clone () at ../sysdeps/unix/sysv/linux/x86_64/clone.S:109

Thread 11 (Thread 0x7f63e5de6700 (LWP 4115)):
#0  0x00007f63f47cfa64 in g_mutex_unlock () from /lib/x86_64-linux-gnu/libglib-2.0.so.0
#1  0x00007f63f478ad49 in g_main_context_check () from /lib/x86_64-linux-gnu/libglib-2.0.so.0
#2  0x00007f63f478b2c0 in ?? () from /lib/x86_64-linux-gnu/libglib-2.0.so.0
#3  0x00007f63f478b42c in g_main_context_iteration () from /lib/x86_64-linux-gnu/libglib-2.0.so.0
#4  0x00007f63f8322a9b in QEventDispatcherGlib::processEvents (this=0x7f63d80008c0, flags=...) at kernel/qeventdispatcher_glib.cpp:420
#5  0x00007f63f82c9dea in QEventLoop::exec (this=this@entry=0x7f63e5de5ce0, flags=..., flags@entry=...) at kernel/qeventloop.cpp:204
#6  0x00007f63f80e68a4 in QThread::exec (this=this@entry=0xa0d5e0) at thread/qthread.cpp:503
#7  0x00007f63fa98e3c5 in QQmlThreadPrivate::run (this=0xa0d5e0) at qml/ftw/qqmlthread.cpp:141
#8  0x00007f63f80eb84e in QThreadPrivate::start (arg=0xa0d5e0) at thread/qthread_unix.cpp:331
#9  0x00007f63f71d86fa in start_thread (arg=0x7f63e5de6700) at pthread_create.c:333
#10 0x00007f63f7a01b5d in clone () at ../sysdeps/unix/sysv/linux/x86_64/clone.S:109

Thread 10 (Thread 0x7f63dde0e700 (LWP 4116)):
#0  pthread_cond_wait@@GLIBC_2.3.2 () at ../sysdeps/unix/sysv/linux/x86_64/pthread_cond_wait.S:185
#1  0x00007f63df38caa3 in ?? () from /usr/lib/x86_64-linux-gnu/dri/swrast_dri.so
#2  0x00007f63df38c907 in ?? () from /usr/lib/x86_64-linux-gnu/dri/swrast_dri.so
#3  0x00007f63f71d86fa in start_thread (arg=0x7f63dde0e700) at pthread_create.c:333
#4  0x00007f63f7a01b5d in clone () at ../sysdeps/unix/sysv/linux/x86_64/clone.S:109

Thread 9 (Thread 0x7f63dd60d700 (LWP 4117)):
#0  pthread_cond_wait@@GLIBC_2.3.2 () at ../sysdeps/unix/sysv/linux/x86_64/pthread_cond_wait.S:185
#1  0x00007f63df38caa3 in ?? () from /usr/lib/x86_64-linux-gnu/dri/swrast_dri.so
#2  0x00007f63df38c907 in ?? () from /usr/lib/x86_64-linux-gnu/dri/swrast_dri.so
#3  0x00007f63f71d86fa in start_thread (arg=0x7f63dd60d700) at pthread_create.c:333
#4  0x00007f63f7a01b5d in clone () at ../sysdeps/unix/sysv/linux/x86_64/clone.S:109

Thread 8 (Thread 0x7f63dce0c700 (LWP 4118)):
#0  pthread_cond_wait@@GLIBC_2.3.2 () at ../sysdeps/unix/sysv/linux/x86_64/pthread_cond_wait.S:185
#1  0x00007f63df38caa3 in ?? () from /usr/lib/x86_64-linux-gnu/dri/swrast_dri.so
#2  0x00007f63df38c907 in ?? () from /usr/lib/x86_64-linux-gnu/dri/swrast_dri.so
#3  0x00007f63f71d86fa in start_thread (arg=0x7f63dce0c700) at pthread_create.c:333
#4  0x00007f63f7a01b5d in clone () at ../sysdeps/unix/sysv/linux/x86_64/clone.S:109

Thread 7 (Thread 0x7f63d562c700 (LWP 4119)):
#0  pthread_cond_wait@@GLIBC_2.3.2 () at ../sysdeps/unix/sysv/linux/x86_64/pthread_cond_wait.S:185
#1  0x00007f63df38caa3 in ?? () from /usr/lib/x86_64-linux-gnu/dri/swrast_dri.so
#2  0x00007f63df38c907 in ?? () from /usr/lib/x86_64-linux-gnu/dri/swrast_dri.so
#3  0x00007f63f71d86fa in start_thread (arg=0x7f63d562c700) at pthread_create.c:333
#4  0x00007f63f7a01b5d in clone () at ../sysdeps/unix/sysv/linux/x86_64/clone.S:109

Thread 6 (Thread 0x7f63d123b700 (LWP 4124)):
#0  0x00007f63f47cfa64 in g_mutex_unlock () from /lib/x86_64-linux-gnu/libglib-2.0.so.0
#1  0x00007f63f478b23e in ?? () from /lib/x86_64-linux-gnu/libglib-2.0.so.0
#2  0x00007f63f478b42c in g_main_context_iteration () from /lib/x86_64-linux-gnu/libglib-2.0.so.0
#3  0x00007f63f8322a9b in QEventDispatcherGlib::processEvents (this=0x7f63cc0008c0, flags=...) at kernel/qeventdispatcher_glib.cpp:420
#4  0x00007f63f82c9dea in QEventLoop::exec (this=this@entry=0x7f63d123ace0, flags=..., flags@entry=...) at kernel/qeventloop.cpp:204
#5  0x00007f63f80e68a4 in QThread::exec (this=this@entry=0x9af2a0) at thread/qthread.cpp:503
#6  0x00007f63fa98e3c5 in QQmlThreadPrivate::run (this=0x9af2a0) at qml/ftw/qqmlthread.cpp:141
#7  0x00007f63f80eb84e in QThreadPrivate::start (arg=0x9af2a0) at thread/qthread_unix.cpp:331
#8  0x00007f63f71d86fa in start_thread (arg=0x7f63d123b700) at pthread_create.c:333
#9  0x00007f63f7a01b5d in clone () at ../sysdeps/unix/sysv/linux/x86_64/clone.S:109

Thread 5 (Thread 0x7f63cb446700 (LWP 4125)):
#0  0x00007f63f79f5e8d in poll () at ../sysdeps/unix/syscall-template.S:84
#1  0x00007f63f478b31c in ?? () from /lib/x86_64-linux-gnu/libglib-2.0.so.0
#2  0x00007f63f478b42c in g_main_context_iteration () from /lib/x86_64-linux-gnu/libglib-2.0.so.0
#3  0x00007f63f8322a9b in QEventDispatcherGlib::processEvents (this=0x7f63c40008c0, flags=...) at kernel/qeventdispatcher_glib.cpp:420
#4  0x00007f63f82c9dea in QEventLoop::exec (this=this@entry=0x7f63cb445ce0, flags=..., flags@entry=...) at kernel/qeventloop.cpp:204
#5  0x00007f63f80e68a4 in QThread::exec (this=this@entry=0xd42f30) at thread/qthread.cpp:503
#6  0x00007f63fa98e3c5 in QQmlThreadPrivate::run (this=0xd42f30) at qml/ftw/qqmlthread.cpp:141
#7  0x00007f63f80eb84e in QThreadPrivate::start (arg=0xd42f30) at thread/qthread_unix.cpp:331
#8  0x00007f63f71d86fa in start_thread (arg=0x7f63cb446700) at pthread_create.c:333
#9  0x00007f63f7a01b5d in clone () at ../sysdeps/unix/sysv/linux/x86_64/clone.S:109

Thread 4 (Thread 0x7f63c9b45700 (LWP 4126)):
#0  pthread_cond_wait@@GLIBC_2.3.2 () at ../sysdeps/unix/sysv/linux/x86_64/pthread_cond_wait.S:185
#1  0x00007f63fcd33bd4 in ?? () from /usr/lib/x86_64-linux-gnu/libQt5Script.so.5
#2  0x00007f63fcd33c19 in ?? () from /usr/lib/x86_64-linux-gnu/libQt5Script.so.5
#3  0x00007f63f71d86fa in start_thread (arg=0x7f63c9b45700) at pthread_create.c:333
#4  0x00007f63f7a01b5d in clone () at ../sysdeps/unix/sysv/linux/x86_64/clone.S:109

Thread 3 (Thread 0x7f6343154700 (LWP 4127)):
#0  0x00007f63f832237e in idleTimerSourcePrepare (source=<optimized out>, timeout=0x7f6343153ad4) at kernel/qeventdispatcher_glib.cpp:208
#1  0x00007f63f478a8ad in g_main_context_prepare () from /lib/x86_64-linux-gnu/libglib-2.0.so.0
#2  0x00007f63f478b24b in ?? () from /lib/x86_64-linux-gnu/libglib-2.0.so.0
#3  0x00007f63f478b42c in g_main_context_iteration () from /lib/x86_64-linux-gnu/libglib-2.0.so.0
#4  0x00007f63f8322a9b in QEventDispatcherGlib::processEvents (this=0x7f633c0008c0, flags=...) at kernel/qeventdispatcher_glib.cpp:420
#5  0x00007f63f82c9dea in QEventLoop::exec (this=this@entry=0x7f6343153c90, flags=..., flags@entry=...) at kernel/qeventloop.cpp:204
#6  0x00007f63f80e68a4 in QThread::exec (this=this@entry=0xf48f50) at thread/qthread.cpp:503
#7  0x00007f63fb314ed6 in QQuickPixmapReader::run (this=0xf48f50) at util/qquickpixmapcache.cpp:817
#8  0x00007f63f80eb84e in QThreadPrivate::start (arg=0xf48f50) at thread/qthread_unix.cpp:331
#9  0x00007f63f71d86fa in start_thread (arg=0x7f6343154700) at pthread_create.c:333
#10 0x00007f63f7a01b5d in clone () at ../sysdeps/unix/sysv/linux/x86_64/clone.S:109

Thread 2 (Thread 0x7f633001e700 (LWP 4128)):
#0  0x00007f63f79f5e8d in poll () at ../sysdeps/unix/syscall-template.S:84
#1  0x00007f63f478b31c in ?? () from /lib/x86_64-linux-gnu/libglib-2.0.so.0
#2  0x00007f63f478b42c in g_main_context_iteration () from /lib/x86_64-linux-gnu/libglib-2.0.so.0
#3  0x00007f63f8322a9b in QEventDispatcherGlib::processEvents (this=0x7f63280008c0, flags=...) at kernel/qeventdispatcher_glib.cpp:420
#4  0x00007f63f82c9dea in QEventLoop::exec (this=this@entry=0x7f633001dcc0, flags=..., flags@entry=...) at kernel/qeventloop.cpp:204
#5  0x00007f63f80e68a4 in QThread::exec (this=<optimized out>) at thread/qthread.cpp:503
#6  0x00007f63324fe7d7 in KCupsConnection::run() () from /usr/lib/x86_64-linux-gnu/libkcupslib.so
#7  0x00007f63f80eb84e in QThreadPrivate::start (arg=0x20dc150) at thread/qthread_unix.cpp:331
#8  0x00007f63f71d86fa in start_thread (arg=0x7f633001e700) at pthread_create.c:333
#9  0x00007f63f7a01b5d in clone () at ../sysdeps/unix/sysv/linux/x86_64/clone.S:109

Thread 1 (Thread 0x7f63fd2d28c0 (LWP 4110)):
[KCrash Handler]
#6  __memmove_ssse3_back () at ../sysdeps/x86_64/multiarch/memcpy-ssse3-back.S:1574
#7  0x00007f63df01c4ad in ?? () from /usr/lib/x86_64-linux-gnu/dri/swrast_dri.so
#8  0x00007f63df01ad95 in ?? () from /usr/lib/x86_64-linux-gnu/dri/swrast_dri.so
#9  0x00007f63e4b1ac1f in Plasma::WindowThumbnail::bindGLXTexture (this=this@entry=0x21c5bb0) at ../../../../src/declarativeimports/core/windowthumbnail.cpp:447
#10 0x00007f63e4b1be44 in Plasma::WindowThumbnail::windowToTextureGLX (this=this@entry=0x21c5bb0, textureNode=textureNode@entry=0x2ccb200) at ../../../../src/declarativeimports/core/windowthumbnail.cpp:282
#11 0x00007f63e4b1c803 in Plasma::WindowThumbnail::windowToTexture (this=0x21c5bb0, textureNode=0x2ccb200) at ../../../../src/declarativeimports/core/windowthumbnail.cpp:394
#12 0x00007f63e4b1cd24 in Plasma::WindowThumbnail::updatePaintNode (this=0x21c5bb0, oldNode=<optimized out>, updatePaintNodeData=<optimized out>) at ../../../../src/declarativeimports/core/windowthumbnail.cpp:199
#13 0x00007f63fb3b32d8 in QQuickWindowPrivate::updateDirtyNode (this=this@entry=0x1c6b4c0, item=item@entry=0x21c5bb0) at items/qquickwindow.cpp:2984
#14 0x00007f63fb3b3b4b in QQuickWindowPrivate::updateDirtyNodes (this=this@entry=0x1c6b4c0) at items/qquickwindow.cpp:2722
#15 0x00007f63fb3b3cc0 in QQuickWindowPrivate::syncSceneGraph (this=this@entry=0x1c6b4c0) at items/qquickwindow.cpp:341
#16 0x00007f63fb38212c in QSGGuiThreadRenderLoop::renderWindow (this=this@entry=0xb46460, window=0x2c76ad0) at scenegraph/qsgrenderloop.cpp:372
#17 0x00007f63fb383aa6 in QSGGuiThreadRenderLoop::exposureChanged (this=0xb46460, window=0x2c76ad0) at scenegraph/qsgrenderloop.cpp:422
#18 0x00007f63f86172e5 in QWindow::event (this=this@entry=0x2c76ad0, ev=ev@entry=0x7ffeb1e632c0) at kernel/qwindow.cpp:2060
#19 0x00007f63fb3bd871 in QQuickWindow::event (this=this@entry=0x2c76ad0, e=e@entry=0x7ffeb1e632c0) at items/qquickwindow.cpp:1413
#20 0x00007f63fce642eb in PlasmaQuick::Dialog::event (this=this@entry=0x2c76ad0, event=event@entry=0x7ffeb1e632c0) at ../../../src/plasmaquick/dialog.cpp:1168
#21 0x00007f63e4b14c45 in ToolTipDialog::event (this=0x2c76ad0, e=0x7ffeb1e632c0) at ../../../../src/declarativeimports/core/tooltipdialog.cpp:120
#22 0x00007f63f8dcf05c in QApplicationPrivate::notify_helper (this=this@entry=0x8fc6a0, receiver=receiver@entry=0x2c76ad0, e=e@entry=0x7ffeb1e632c0) at kernel/qapplication.cpp:3716
#23 0x00007f63f8dd4516 in QApplication::notify (this=0x7ffeb1e636e0, receiver=0x2c76ad0, e=0x7ffeb1e632c0) at kernel/qapplication.cpp:3499
#24 0x00007f63f82cc62b in QCoreApplication::notifyInternal (this=0x7ffeb1e636e0, receiver=receiver@entry=0x2c76ad0, event=event@entry=0x7ffeb1e632c0) at kernel/qcoreapplication.cpp:965
#25 0x00007f63f860f4ec in QCoreApplication::sendSpontaneousEvent (event=0x7ffeb1e632c0, receiver=0x2c76ad0) at ../../include/QtCore/../../src/corelib/kernel/qcoreapplication.h:227
#26 QGuiApplicationPrivate::processExposeEvent (e=0x2c1c3d0) at kernel/qguiapplication.cpp:2663
#27 0x00007f63f861025d in QGuiApplicationPrivate::processWindowSystemEvent (e=e@entry=0x2c1c3d0) at kernel/qguiapplication.cpp:1658
#28 0x00007f63f85f3f38 in QWindowSystemInterface::sendWindowSystemEvents (flags=...) at kernel/qwindowsysteminterface.cpp:625
#29 0x00007f63ea773f10 in userEventSourceDispatch (source=<optimized out>) at eventdispatchers/qeventdispatcher_glib.cpp:70
#30 0x00007f63f478b127 in g_main_context_dispatch () from /lib/x86_64-linux-gnu/libglib-2.0.so.0
#31 0x00007f63f478b380 in ?? () from /lib/x86_64-linux-gnu/libglib-2.0.so.0
#32 0x00007f63f478b42c in g_main_context_iteration () from /lib/x86_64-linux-gnu/libglib-2.0.so.0
#33 0x00007f63f8322a7f in QEventDispatcherGlib::processEvents (this=0x93b020, flags=...) at kernel/qeventdispatcher_glib.cpp:418
#34 0x00007f63f82c9dea in QEventLoop::exec (this=this@entry=0x7ffeb1e63580, flags=..., flags@entry=...) at kernel/qeventloop.cpp:204
#35 0x00007f63f82d1e8c in QCoreApplication::exec () at kernel/qcoreapplication.cpp:1229
#36 0x00007f63f8605c3c in QGuiApplication::exec () at kernel/qguiapplication.cpp:1542
#37 0x00007f63f8dcb495 in QApplication::exec () at kernel/qapplication.cpp:2976
#38 0x0000000000432d4a in main (argc=4, argv=<optimized out>) at /build/plasma-workspace-kxRFE_/plasma-workspace-5.5.5.2/shell/main.cpp:181

Possible duplicates by query: bug 362509, bug 362461, bug 362168, bug 359825.

Reported using DrKonqi