Bug 345096

Application: kwin_x11 (5.2.1)

Qt Version: 5.4.0
Operating System: Linux 3.19.0-7-generic x86_64
Distribution: Ubuntu Vivid Vervet (development branch)

-- Information about the crash:
- What I was doing when the application crashed:
waking up laptop from stand by after having detached it from docking station (which has two screens)

- Unusual behavior I noticed:
KWin crashes. Additionally, it's "very difficult" to enter the password to unlock the screen. Somehow it seems whatever I type is not considered, but then eventually the password is read.

The crash can be reproduced every time.

-- Backtrace:
Application: KWin (kwin_x11), signal: Segmentation fault
Using host libthread_db library "/lib/x86_64-linux-gnu/libthread_db.so.1".
[Current thread is 1 (Thread 0x7f9f94140840 (LWP 26794))]

Thread 3 (Thread 0x7f9f76dee700 (LWP 26899)):
#0  0x00007f9f93c11ef3 in select () at ../sysdeps/unix/syscall-template.S:81
#1  0x00007f9f92468fa1 in qt_safe_select (nfds=14, fdread=fdread@entry=0x7f9f68000a78, fdwrite=fdwrite@entry=0x7f9f68000d08, fdexcept=fdexcept@entry=0x7f9f68000f98, orig_timeout=orig_timeout@entry=0x0) at kernel/qcore_unix.cpp:75
#2  0x00007f9f9246ab5c in select (timeout=0x0, exceptfds=0x7f9f68000f98, writefds=0x7f9f68000d08, readfds=0x7f9f68000a78, nfds=<optimized out>, this=0x7f9f680008c0) at kernel/qeventdispatcher_unix.cpp:320
#3  QEventDispatcherUNIXPrivate::doSelect (this=this@entry=0x7f9f680008e0, flags=..., flags@entry=..., timeout=timeout@entry=0x0) at kernel/qeventdispatcher_unix.cpp:196
#4  0x00007f9f9246b0d5 in QEventDispatcherUNIX::processEvents (this=0x7f9f680008c0, flags=...) at kernel/qeventdispatcher_unix.cpp:607
#5  0x00007f9f92412392 in QEventLoop::exec (this=this@entry=0x7f9f76dedd60, flags=..., flags@entry=...) at kernel/qeventloop.cpp:204
#6  0x00007f9f921d1a94 in QThread::exec (this=<optimized out>) at thread/qthread.cpp:503
#7  0x00007f9f8c080865 in ?? () from /usr/lib/x86_64-linux-gnu/libQt5Qml.so.5
#8  0x00007f9f921d6a4e in QThreadPrivate::start (arg=0xc4cd20) at thread/qthread_unix.cpp:337
#9  0x00007f9f8b2490a5 in start_thread (arg=0x7f9f76dee700) at pthread_create.c:309
#10 0x00007f9f93c1a57d in clone () at ../sysdeps/unix/sysv/linux/x86_64/clone.S:111

Thread 2 (Thread 0x7f9f67fff700 (LWP 26920)):
#0  pthread_cond_wait@@GLIBC_2.3.2 () at ../nptl/sysdeps/unix/sysv/linux/x86_64/pthread_cond_wait.S:185
#1  0x00007f9f90fdf684 in ?? () from /usr/lib/x86_64-linux-gnu/libQt5Script.so.5
#2  0x00007f9f90fdf6c9 in ?? () from /usr/lib/x86_64-linux-gnu/libQt5Script.so.5
#3  0x00007f9f8b2490a5 in start_thread (arg=0x7f9f67fff700) at pthread_create.c:309
#4  0x00007f9f93c1a57d in clone () at ../sysdeps/unix/sysv/linux/x86_64/clone.S:111

Thread 1 (Thread 0x7f9f94140840 (LWP 26794)):
[KCrash Handler]
#6  QScreen::handle (this=0x0) at kernel/qscreen.cpp:85
#7  0x00007f9f7f1e48f5 in QXcbWindow::QXcbWindow (this=0x1632150, window=0x14d8e20) at qxcbwindow.cpp:244
#8  0x00007f9f7f1d25e1 in QXcbIntegration::createPlatformWindow (this=<optimized out>, window=0x14d8e20) at qxcbintegration.cpp:175
#9  0x00007f9f927664f6 in QWindowPrivate::create (this=0x14d7df0, recursive=recursive@entry=false) at kernel/qwindow.cpp:395
#10 0x00007f9f927666eb in QWindow::create (this=this@entry=0x14d8e20) at kernel/qwindow.cpp:530
#11 0x00007f9f92766898 in QWindow::winId (this=0x14d8e20) at kernel/qwindow.cpp:549
#12 0x00007f9f93800dff in KWin::AbstractThumbnailItem::findParentEffectWindow (this=0x15f92c0) at ../thumbnailitem.cpp:79
#13 0x00007f9f93800fc9 in KWin::AbstractThumbnailItem::effectWindowAdded (this=0x15f92c0) at ../thumbnailitem.cpp:90
#14 0x00007f9f9388b285 in KWin::AbstractThumbnailItem::qt_static_metacall (_o=0x0, _c=2481842040, _id=23593280, _a=0x7f9f93ede760 <main_arena>) at moc_thumbnailitem.cpp:130
#15 0x00007f9f92445959 in QMetaObject::activate (sender=0x133af10, signalOffset=<optimized out>, local_signal_index=local_signal_index@entry=5, argv=argv@entry=0x7fff174fcaa0) at kernel/qobject.cpp:3716
#16 0x00007f9f92445fe7 in QMetaObject::activate (sender=<optimized out>, m=m@entry=0x7f9f91c03ac0 <KWin::EffectsHandler::staticMetaObject>, local_signal_index=local_signal_index@entry=5, argv=argv@entry=0x7fff174fcaa0) at kernel/qobject.cpp:3582
#17 0x00007f9f919f4fb2 in KWin::EffectsHandler::windowAdded (this=<optimized out>, _t1=0x19f7870) at moc_kwineffects.cpp:1195
#18 0x00007f9f924452ea in call (a=0x7fff174fcbe0, r=0x133af10, this=0xb25e80) at ../../include/QtCore/../../src/corelib/kernel/qobject_impl.h:124
#19 QMetaObject::activate (sender=sender@entry=0xb1b110, signalOffset=<optimized out>, local_signal_index=local_signal_index@entry=7, argv=argv@entry=0x7fff174fcbe0) at kernel/qobject.cpp:3702
#20 0x00007f9f92445fe7 in QMetaObject::activate (sender=sender@entry=0xb1b110, m=m@entry=0x7f9f93b142e0 <KWin::Toplevel::staticMetaObject>, local_signal_index=local_signal_index@entry=7, argv=argv@entry=0x7fff174fcbe0) at kernel/qobject.cpp:3582
#21 0x00007f9f93886122 in KWin::Toplevel::windowShown (this=this@entry=0xb1b110, _t1=_t1@entry=0xb1b110) at moc_toplevel.cpp:656
#22 0x00007f9f937ccdff in KWin::Toplevel::setReadyForPainting (this=0xb1b110) at ../toplevel.cpp:245
#23 0x00007f9f9388c0c5 in KWin::Toplevel::qt_static_metacall (_o=0x0, _c=2481842040, _id=23593280, _a=0x7f9f93ede760 <main_arena>) at moc_toplevel.cpp:327
#24 0x00007f9f92445959 in QMetaObject::activate (sender=sender@entry=0x13c1580, signalOffset=<optimized out>, local_signal_index=local_signal_index@entry=0, argv=argv@entry=0x0) at kernel/qobject.cpp:3716
#25 0x00007f9f92445fe7 in QMetaObject::activate (sender=sender@entry=0x13c1580, m=m@entry=0x7f9f9266c080 <QSingleShotTimer::staticMetaObject>, local_signal_index=local_signal_index@entry=0, argv=argv@entry=0x0) at kernel/qobject.cpp:3582
#26 0x00007f9f9245363b in timeout (this=0x13c1580) at .moc/qtimer.moc:122
#27 QSingleShotTimer::timerEvent (this=0x13c1580) at kernel/qtimer.cpp:318
#28 0x00007f9f92446683 in QObject::event (this=0x13c1580, e=<optimized out>) at kernel/qobject.cpp:1267
#29 0x00007f9f92d1d2ec in QApplicationPrivate::notify_helper (this=0xb04940, receiver=0x13c1580, e=0x7fff174fd050) at kernel/qapplication.cpp:3722
#30 0x00007f9f92d22960 in QApplication::notify (this=0x7fff174fd290, receiver=0x13c1580, e=0x7fff174fd050) at kernel/qapplication.cpp:3505
#31 0x00007f9f92414bdb in QCoreApplication::notifyInternal (this=0x7fff174fd290, receiver=0x13c1580, event=event@entry=0x7fff174fd050) at kernel/qcoreapplication.cpp:932
#32 0x00007f9f9246c945 in sendEvent (event=0x7fff174fd050, receiver=<optimized out>) at ../../include/QtCore/../../src/corelib/kernel/qcoreapplication.h:228
#33 QTimerInfoList::activateTimers (this=0xb37558) at kernel/qtimerinfo_unix.cpp:635
#34 0x00007f9f9246a530 in QEventDispatcherUNIX::activateTimers (this=this@entry=0xb3e4d0) at kernel/qeventdispatcher_unix.cpp:549
#35 0x00007f9f9246b0a3 in QEventDispatcherUNIX::processEvents (this=0xb3e4d0, flags=flags@entry=...) at kernel/qeventdispatcher_unix.cpp:611
#36 0x00007f9f7f22689d in QUnixEventDispatcherQPA::processEvents (this=<optimized out>, flags=...) at eventdispatchers/qunixeventdispatcher.cpp:62
#37 0x00007f9f92412392 in QEventLoop::exec (this=this@entry=0x7fff174fd1b0, flags=..., flags@entry=...) at kernel/qeventloop.cpp:204
#38 0x00007f9f92419fdc in QCoreApplication::exec () at kernel/qcoreapplication.cpp:1185
#39 0x00007f9f9275919c in QGuiApplication::exec () at kernel/qguiapplication.cpp:1535
#40 0x00007f9f92d18f55 in QApplication::exec () at kernel/qapplication.cpp:2956
#41 0x00007f9f93ee98c3 in kdemain (argc=3, argv=0x7fff174fd3e8) at ../main_x11.cpp:294
#42 0x00007f9f93b41ec5 in __libc_start_main (main=0x400790 <main(int, char**)>, argc=3, argv=0x7fff174fd3e8, init=<optimized out>, fini=<optimized out>, rtld_fini=<optimized out>, stack_end=0x7fff174fd3d8) at libc-start.c:287
#43 0x00000000004007be in _start ()

Reported using DrKonqi