Application: kwin_x11 (5.8.6)

Qt Version: 5.6.1
Frameworks Version: 5.33.0
Operating System: Linux 4.4.0-78-generic x86_64
Distribution: Ubuntu 16.04.2 LTS

-- Information about the crash:
I had just rebooted the system. KDE was starting. Normally KDE will occasionaly crash maybe once a day, however this was the first time it crashed on starting. I had Skype and clocks displayed before the desktop or plasma panel. Previously I hadn't had Skype & clock installed.  Could these windows being displayed while the rest of the screen is blank cause kwin to crash ?

-- Backtrace:
Application: KWin (kwin_x11), 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 ../sysdeps/unix/sysv/linux/x86_64/pthread_cond_wait.S:185
[Current thread is 1 (Thread 0x7fcffd4fb940 (LWP 3019))]

Thread 6 (Thread 0x7fcfc77fe700 (LWP 3371)):
#0  pthread_cond_wait@@GLIBC_2.3.2 () at ../sysdeps/unix/sysv/linux/x86_64/pthread_cond_wait.S:185
#1  0x00007fcff9b6a574 in ?? () from /usr/lib/x86_64-linux-gnu/libQt5Script.so.5
#2  0x00007fcff9b6a5b9 in ?? () from /usr/lib/x86_64-linux-gnu/libQt5Script.so.5
#3  0x00007fcffccd56ba in start_thread (arg=0x7fcfc77fe700) at pthread_create.c:333
#4  0x00007fcffcff482d in clone () at ../sysdeps/unix/sysv/linux/x86_64/clone.S:109

Thread 5 (Thread 0x7fcfd943c700 (LWP 3228)):
[KCrash Handler]
#6  0x00007fcffa94a413 in QString::toLocal8Bit() const & (this=0x231ef60) at ../../include/QtCore/../../src/corelib/tools/qstring.h:517
#7  QFile::encodeName (fileName=...) at ../../include/QtCore/../../src/corelib/io/qfile.h:82
#8  QLockFilePrivate::tryLock_sys (this=this@entry=0x231ef60) at io/qlockfile_unix.cpp:180
#9  0x00007fcffa8e7a80 in QLockFile::tryLock (this=<optimized out>, timeout=-1) at io/qlockfile.cpp:212
#10 0x00007fcffbf65f79 in ?? () from /usr/lib/x86_64-linux-gnu/libKF5ConfigCore.so.5
#11 0x00007fcffbf50187 in KConfig::sync() () from /usr/lib/x86_64-linux-gnu/libKF5ConfigCore.so.5
#12 0x00007fcfe0466175 in ?? () from /usr/lib/x86_64-linux-gnu/qt5/plugins/org.kde.kwin.platforms/KWinX11Platform.so
#13 0x00007fcffa9e4c24 in QtPrivate::QSlotObjectBase::call (a=0x7fcfd943b830, r=0x1dabf00, this=<optimized out>) at ../../include/QtCore/../../src/corelib/kernel/qobject_impl.h:124
#14 QMetaObject::activate (sender=sender@entry=0x1dabf00, signalOffset=<optimized out>, local_signal_index=local_signal_index@entry=0, argv=argv@entry=0x0) at kernel/qobject.cpp:3715
#15 0x00007fcffa9e51b7 in QMetaObject::activate (sender=sender@entry=0x1dabf00, m=m@entry=0x7fcffac00720 <QTimer::staticMetaObject>, local_signal_index=local_signal_index@entry=0, argv=argv@entry=0x0) at kernel/qobject.cpp:3595
#16 0x00007fcffaa5fe80 in QTimer::timeout (this=this@entry=0x1dabf00) at .moc/moc_qtimer.cpp:198
#17 0x00007fcffa9f10b8 in QTimer::timerEvent (this=0x1dabf00, e=<optimized out>) at kernel/qtimer.cpp:247
#18 0x00007fcffa9e56d3 in QObject::event (this=0x1dabf00, e=<optimized out>) at kernel/qobject.cpp:1278
#19 0x00007fcffb2faafc in QApplicationPrivate::notify_helper (this=<optimized out>, receiver=0x1dabf00, e=0x7fcfd943bb40) at kernel/qapplication.cpp:3804
#20 0x00007fcffb300036 in QApplication::notify (this=0x7ffdfa87a3b0, receiver=0x1dabf00, e=0x7fcfd943bb40) at kernel/qapplication.cpp:3561
#21 0x00007fcffa9b82a8 in QCoreApplication::notifyInternal2 (receiver=0x1dabf00, event=event@entry=0x7fcfd943bb40) at kernel/qcoreapplication.cpp:1015
#22 0x00007fcffaa0c24e in QCoreApplication::sendEvent (event=0x7fcfd943bb40, receiver=<optimized out>) at ../../include/QtCore/../../src/corelib/kernel/qcoreapplication.h:225
#23 QTimerInfoList::activateTimers (this=0x7fcfcc001138) at kernel/qtimerinfo_unix.cpp:637
#24 0x00007fcffaa0a060 in QEventDispatcherUNIX::activateTimers (this=this@entry=0x7fcfcc0008e0) at kernel/qeventdispatcher_unix.cpp:549
#25 0x00007fcffaa0ab04 in QEventDispatcherUNIX::processEvents (this=0x7fcfcc0008e0, flags=...) at kernel/qeventdispatcher_unix.cpp:611
#26 0x00007fcffa9b5ffa in QEventLoop::exec (this=this@entry=0x7fcfd943bc80, flags=..., flags@entry=...) at kernel/qeventloop.cpp:204
#27 0x00007fcffa7de9e4 in QThread::exec (this=<optimized out>) at thread/qthread.cpp:500
#28 0x00007fcffa7e3808 in QThreadPrivate::start (arg=0x1e18400) at thread/qthread_unix.cpp:341
#29 0x00007fcffccd56ba in start_thread (arg=0x7fcfd943c700) at pthread_create.c:333
#30 0x00007fcffcff482d in clone () at ../sysdeps/unix/sysv/linux/x86_64/clone.S:109

Thread 4 (Thread 0x7fcfda51d700 (LWP 3204)):
#0  0x00007fcffcfea9e3 in select () at ../sysdeps/unix/syscall-template.S:84
#1  0x00007fcffaa08bcf in qt_safe_select (nfds=14, fdread=fdread@entry=0x7fcfc8000a98, fdwrite=fdwrite@entry=0x7fcfc8000d28, fdexcept=fdexcept@entry=0x7fcfc8000fb8, orig_timeout=orig_timeout@entry=0x0) at kernel/qcore_unix.cpp:75
#2  0x00007fcffaa0a60e in QEventDispatcherUNIX::select (timeout=0x0, exceptfds=0x7fcfc8000fb8, writefds=0x7fcfc8000d28, readfds=0x7fcfc8000a98, nfds=<optimized out>, this=0x7fcfc80008e0) at kernel/qeventdispatcher_unix.cpp:320
#3  QEventDispatcherUNIXPrivate::doSelect (this=this@entry=0x7fcfc8000900, flags=..., flags@entry=..., timeout=timeout@entry=0x0) at kernel/qeventdispatcher_unix.cpp:196
#4  0x00007fcffaa0ab22 in QEventDispatcherUNIX::processEvents (this=0x7fcfc80008e0, flags=...) at kernel/qeventdispatcher_unix.cpp:607
#5  0x00007fcffa9b5ffa in QEventLoop::exec (this=this@entry=0x7fcfda51cc60, flags=..., flags@entry=...) at kernel/qeventloop.cpp:204
#6  0x00007fcffa7de9e4 in QThread::exec (this=this@entry=0x1f19600) at thread/qthread.cpp:500
#7  0x00007fcff5b566b5 in QQmlThreadPrivate::run (this=0x1f19600) at qml/ftw/qqmlthread.cpp:141
#8  0x00007fcffa7e3808 in QThreadPrivate::start (arg=0x1f19600) at thread/qthread_unix.cpp:341
#9  0x00007fcffccd56ba in start_thread (arg=0x7fcfda51d700) at pthread_create.c:333
#10 0x00007fcffcff482d in clone () at ../sysdeps/unix/sysv/linux/x86_64/clone.S:109

Thread 3 (Thread 0x7fcfe0e85700 (LWP 3151)):
#0  0x00007fcffcfea9e3 in select () at ../sysdeps/unix/syscall-template.S:84
#1  0x00007fcffaa08bcf in qt_safe_select (nfds=8, fdread=fdread@entry=0x7fcfd4000a98, fdwrite=fdwrite@entry=0x7fcfd4000d28, fdexcept=fdexcept@entry=0x7fcfd4000fb8, orig_timeout=orig_timeout@entry=0x0) at kernel/qcore_unix.cpp:75
#2  0x00007fcffaa0a60e in QEventDispatcherUNIX::select (timeout=0x0, exceptfds=0x7fcfd4000fb8, writefds=0x7fcfd4000d28, readfds=0x7fcfd4000a98, nfds=<optimized out>, this=0x7fcfd40008e0) at kernel/qeventdispatcher_unix.cpp:320
#3  QEventDispatcherUNIXPrivate::doSelect (this=this@entry=0x7fcfd4000900, flags=..., flags@entry=..., timeout=timeout@entry=0x0) at kernel/qeventdispatcher_unix.cpp:196
#4  0x00007fcffaa0ab22 in QEventDispatcherUNIX::processEvents (this=0x7fcfd40008e0, flags=...) at kernel/qeventdispatcher_unix.cpp:607
#5  0x00007fcffa9b5ffa in QEventLoop::exec (this=this@entry=0x7fcfe0e84c50, flags=..., flags@entry=...) at kernel/qeventloop.cpp:204
#6  0x00007fcffa7de9e4 in QThread::exec (this=this@entry=0x7fcff4f96d40 <(anonymous namespace)::Q_QGS__q_manager::innerFunction()::holder>) at thread/qthread.cpp:500
#7  0x00007fcff4f23515 in QDBusConnectionManager::run (this=0x7fcff4f96d40 <(anonymous namespace)::Q_QGS__q_manager::innerFunction()::holder>) at qdbusconnection.cpp:189
#8  0x00007fcffa7e3808 in QThreadPrivate::start (arg=0x7fcff4f96d40 <(anonymous namespace)::Q_QGS__q_manager::innerFunction()::holder>) at thread/qthread_unix.cpp:341
#9  0x00007fcffccd56ba in start_thread (arg=0x7fcfe0e85700) at pthread_create.c:333
#10 0x00007fcffcff482d in clone () at ../sysdeps/unix/sysv/linux/x86_64/clone.S:109

Thread 2 (Thread 0x7fcfe2e7d700 (LWP 3100)):
#0  0x00007fcffcfe8b5d in poll () at ../sysdeps/unix/syscall-template.S:84
#1  0x00007fcffbd17c62 in ?? () from /usr/lib/x86_64-linux-gnu/libxcb.so.1
#2  0x00007fcffbd198d7 in xcb_wait_for_event () from /usr/lib/x86_64-linux-gnu/libxcb.so.1
#3  0x00007fcfe3b40d29 in QXcbEventReader::run (this=0x1c45580) at qxcbconnection.cpp:1325
#4  0x00007fcffa7e3808 in QThreadPrivate::start (arg=0x1c45580) at thread/qthread_unix.cpp:341
#5  0x00007fcffccd56ba in start_thread (arg=0x7fcfe2e7d700) at pthread_create.c:333
#6  0x00007fcffcff482d in clone () at ../sysdeps/unix/sysv/linux/x86_64/clone.S:109

Thread 1 (Thread 0x7fcffd4fb940 (LWP 3019)):
#0  pthread_cond_wait@@GLIBC_2.3.2 () at ../sysdeps/unix/sysv/linux/x86_64/pthread_cond_wait.S:185
#1  0x00007fcffbd17eb9 in ?? () from /usr/lib/x86_64-linux-gnu/libxcb.so.1
#2  0x00007fcffbd19617 in ?? () from /usr/lib/x86_64-linux-gnu/libxcb.so.1
#3  0x00007fcffbd19721 in xcb_wait_for_reply () from /usr/lib/x86_64-linux-gnu/libxcb.so.1
#4  0x00007fcfe3b3fa2a in QXcbConnection::sync (this=this@entry=0x1c35e60) at qxcbconnection.cpp:2063
#5  0x00007fcfe3b40f38 in QXcbConnection::getTimestamp (this=0x1c35e60) at qxcbconnection.cpp:1454
#6  0x00007fcfe3b60d62 in QXcbNativeInterface::getTimestamp (this=this@entry=0x1c29150, screen=screen@entry=0x1c50100) at qxcbnativeinterface.cpp:399
#7  0x00007fcfe3b61cd1 in QXcbNativeInterface::nativeResourceForScreen (this=0x1c29150, resourceString=..., screen=0x1c45ae0) at qxcbnativeinterface.cpp:247
#8  0x00007fcffd6ef9d0 in QX11Info::getTimestamp() () from /usr/lib/x86_64-linux-gnu/libQt5X11Extras.so.5
#9  0x00007fcffc6dec09 in ?? () from /usr/lib/x86_64-linux-gnu/libkwin.so.5
#10 0x00007fcffc6f44db in KWin::Workspace::workspaceEvent(xcb_generic_event_t*) () from /usr/lib/x86_64-linux-gnu/libkwin.so.5
#11 0x00007fcffa9b516f in QAbstractEventDispatcher::filterNativeEvent (this=<optimized out>, eventType=..., message=message@entry=0x7fcfdc0026f0, result=result@entry=0x7ffdfa879d78) at kernel/qabstracteventdispatcher.cpp:460
#12 0x00007fcfe3b44ca5 in QXcbConnection::handleXcbEvent (this=this@entry=0x1c35e60, event=event@entry=0x7fcfdc0026f0) at qxcbconnection.cpp:1091
#13 0x00007fcfe3b45c06 in QXcbConnection::processXcbEvents (this=0x1c35e60) at qxcbconnection.cpp:1723
#14 0x00007fcffa9e5719 in QObject::event (this=0x1c35e60, e=<optimized out>) at kernel/qobject.cpp:1256
#15 0x00007fcffb2faafc in QApplicationPrivate::notify_helper (this=<optimized out>, receiver=0x1c35e60, e=0x7fcfdc005ad0) at kernel/qapplication.cpp:3804
#16 0x00007fcffb300036 in QApplication::notify (this=0x7ffdfa87a3b0, receiver=0x1c35e60, e=0x7fcfdc005ad0) at kernel/qapplication.cpp:3561
#17 0x00007fcffa9b82a8 in QCoreApplication::notifyInternal2 (receiver=0x1c35e60, event=event@entry=0x7fcfdc005ad0) at kernel/qcoreapplication.cpp:1015
#18 0x00007fcffa9ba16a in QCoreApplication::sendEvent (event=0x7fcfdc005ad0, receiver=<optimized out>) at ../../include/QtCore/../../src/corelib/kernel/qcoreapplication.h:225
#19 QCoreApplicationPrivate::sendPostedEvents (receiver=receiver@entry=0x0, event_type=event_type@entry=0, data=0x1c16610) at kernel/qcoreapplication.cpp:1650
#20 0x00007fcffaa0aa02 in QEventDispatcherUNIX::processEvents (this=0x1c7d630, flags=flags@entry=...) at kernel/qeventdispatcher_unix.cpp:579
#21 0x00007fcfe3bb48fd in QUnixEventDispatcherQPA::processEvents (this=<optimized out>, flags=...) at eventdispatchers/qunixeventdispatcher.cpp:62
#22 0x00007fcffa9b5ffa in QEventLoop::exec (this=this@entry=0x7ffdfa87a2a0, flags=..., flags@entry=...) at kernel/qeventloop.cpp:204
#23 0x00007fcffa9be6bc in QCoreApplication::exec () at kernel/qcoreapplication.cpp:1285
#24 0x00007fcffd2c7226 in kdemain () from /usr/lib/x86_64-linux-gnu/libkdeinit5_kwin_x11.so
#25 0x00007fcffcf0e830 in __libc_start_main (main=0x400730, argc=3, argv=0x7ffdfa87a538, init=<optimized out>, fini=<optimized out>, rtld_fini=<optimized out>, stack_end=0x7ffdfa87a528) at ../csu/libc-start.c:291
#26 0x0000000000400769 in _start ()

Possible duplicates by query: bug 374755, bug 372114.

Reported using DrKonqi