Application: kwin_x11 (5.2.2)

Qt Version: 5.4.1
Operating System: Linux 3.19.0-22-generic x86_64
Distribution: Ubuntu 15.04

-- Information about the crash:
booting uo until almost done, then screen gioes black
may be session apps crashing

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 0x7f344d146800 (LWP 19821))]

Thread 3 (Thread 0x7f3428820700 (LWP 19841)):
#0  0x00007f344cc248dd in poll () at ../sysdeps/unix/syscall-template.S:81
#1  0x00007f3443d39ebc in ?? () from /lib/x86_64-linux-gnu/libglib-2.0.so.0
#2  0x00007f3443d3a242 in g_main_loop_run () from /lib/x86_64-linux-gnu/libglib-2.0.so.0
#3  0x00007f342f827af6 in ?? () from /usr/lib/x86_64-linux-gnu/libgio-2.0.so.0
#4  0x00007f3443d60955 in ?? () from /lib/x86_64-linux-gnu/libglib-2.0.so.0
#5  0x00007f34433e5754 in ?? () from /usr/lib/nvidia-304/libGL.so.1
#6  0x00007f34442586aa in start_thread (arg=0x7f3428820700) at pthread_create.c:333
#7  0x00007f344cc2feed in clone () at ../sysdeps/unix/sysv/linux/x86_64/clone.S:109

Thread 2 (Thread 0x7f3423fff700 (LWP 19843)):
#0  0x00007f344cc248dd in poll () at ../sysdeps/unix/syscall-template.S:81
#1  0x00007f3443d39ebc in ?? () from /lib/x86_64-linux-gnu/libglib-2.0.so.0
#2  0x00007f3443d39fcc in g_main_context_iteration () from /lib/x86_64-linux-gnu/libglib-2.0.so.0
#3  0x00007f3443d3a009 in ?? () from /lib/x86_64-linux-gnu/libglib-2.0.so.0
#4  0x00007f3443d60955 in ?? () from /lib/x86_64-linux-gnu/libglib-2.0.so.0
#5  0x00007f34433e5754 in ?? () from /usr/lib/nvidia-304/libGL.so.1
#6  0x00007f34442586aa in start_thread (arg=0x7f3423fff700) at pthread_create.c:333
#7  0x00007f344cc2feed in clone () at ../sysdeps/unix/sysv/linux/x86_64/clone.S:109

Thread 1 (Thread 0x7f344d146800 (LWP 19821)):
[KCrash Handler]
#6  xcb_setup_vendor_end (R=R@entry=0x0) at xproto.c:1569
#7  0x00007f344af29059 in xcb_setup_pixmap_formats_iterator (R=R@entry=0x0) at xproto.c:1622
#8  0x00007f344af29099 in xcb_setup_roots_iterator (R=0x0) at xproto.c:1659
#9  0x00007f344c7490f8 in defaultScreen () at ../libkwineffects/kwinglobals.h:170
#10 KWin::ColorMapper::ColorMapper (this=this@entry=0x12f7180, parent=parent@entry=0x12e8b20) at ../workspace.cpp:82
#11 0x00007f344c751371 in KWin::Workspace::Workspace (this=0x12e8b20, restore=<optimized out>) at ../workspace.cpp:172
#12 0x00007f344cef6aa6 in operator() (__closure=<synthetic pointer>) at ../main_x11.cpp:170
#13 call (arg=<optimized out>, f=...) at /usr/include/x86_64-linux-gnu/qt5/QtCore/qobjectdefs_impl.h:494
#14 call<QtPrivate::List<>, void> (arg=<optimized out>, f=...) at /usr/include/x86_64-linux-gnu/qt5/QtCore/qobjectdefs_impl.h:551
#15 QtPrivate::QFunctorSlotObject<KWin::ApplicationX11::performStartup()::<lambda()>, 0, QtPrivate::List<>, void>::impl(int, QtPrivate::QSlotObjectBase *, QObject *, void **, bool *) (which=<optimized out>, this_=<optimized out>, r=<optimized out>, a=<optimized out>, ret=<optimized out>) at /usr/include/x86_64-linux-gnu/qt5/QtCore/qobject_impl.h:192
#16 0x00007f344b44c35a in call (a=0x7ffcf7b8ac90, r=0x12d4520, this=0x12d4770) at ../../include/QtCore/../../src/corelib/kernel/qobject_impl.h:124
#17 QMetaObject::activate (sender=0x12d4520, signalOffset=<optimized out>, local_signal_index=local_signal_index@entry=1, argv=argv@entry=0x0) at kernel/qobject.cpp:3702
#18 0x00007f344b44d057 in QMetaObject::activate (sender=<optimized out>, m=m@entry=0x7f344c4c1bc0 <KSelectionOwner::staticMetaObject>, local_signal_index=local_signal_index@entry=1, argv=argv@entry=0x0) at kernel/qobject.cpp:3582
#19 0x00007f344c2b10e3 in KSelectionOwner::claimedOwnership (this=<optimized out>) at moc_kselectionowner.cpp:150
#20 0x00007f344c294a9b in KSelectionOwner::Private::claimSucceeded (this=0x12d3cc0) at ../../src/kselectionowner.cpp:206
#21 0x00007f344c295221 in KSelectionOwner::filterEvent (this=0x12d4520, ev_P=<optimized out>) at ../../src/kselectionowner.cpp:424
#22 0x00007f344b418510 in QAbstractEventDispatcher::filterNativeEvent (this=this@entry=0x11b6190, eventType=..., message=message@entry=0x7f34300015c0, result=result@entry=0x7ffcf7b8ae28) at kernel/qabstracteventdispatcher.cpp:460
#23 0x00007f3436bf602d in QXcbConnection::handleXcbEvent (this=this@entry=0x10cc960, event=event@entry=0x7f34300015c0) at qxcbconnection.cpp:863
#24 0x00007f3436bf74bb in QXcbConnection::processXcbEvents (this=0x10cc960) at qxcbconnection.cpp:1303
#25 0x00007f344b44d73a in QObject::event (this=0x10cc960, e=<optimized out>) at kernel/qobject.cpp:1245
#26 0x00007f344bd25b2c in QApplicationPrivate::notify_helper (this=0x10be100, receiver=0x10cc960, e=0x7f3430001630) at kernel/qapplication.cpp:3720
#27 0x00007f344bd2b000 in QApplication::notify (this=0x7ffcf7b8b510, receiver=0x10cc960, e=0x7f3430001630) at kernel/qapplication.cpp:3503
#28 0x00007f344b41bc2b in QCoreApplication::notifyInternal (this=0x7ffcf7b8b510, receiver=0x10cc960, event=event@entry=0x7f3430001630) at kernel/qcoreapplication.cpp:935
#29 0x00007f344b41dc9b in sendEvent (event=0x7f3430001630, receiver=<optimized out>) at ../../include/QtCore/../../src/corelib/kernel/qcoreapplication.h:228
#30 QCoreApplicationPrivate::sendPostedEvents (receiver=receiver@entry=0x0, event_type=event_type@entry=0, data=0x10af010) at kernel/qcoreapplication.cpp:1552
#31 0x00007f344b472112 in QEventDispatcherUNIX::processEvents (this=0x11b6190, flags=flags@entry=...) at kernel/qeventdispatcher_unix.cpp:579
#32 0x00007f3436c4d96d in QUnixEventDispatcherQPA::processEvents (this=<optimized out>, flags=...) at eventdispatchers/qunixeventdispatcher.cpp:62
#33 0x00007f344b4193e2 in QEventLoop::exec (this=this@entry=0x7ffcf7b8b430, flags=..., flags@entry=...) at kernel/qeventloop.cpp:204
#34 0x00007f344b42102c in QCoreApplication::exec () at kernel/qcoreapplication.cpp:1188
#35 0x00007f344b76031c in QGuiApplication::exec () at kernel/qguiapplication.cpp:1510
#36 0x00007f344bd217a5 in QApplication::exec () at kernel/qapplication.cpp:2956
#37 0x00007f344cef78c3 in kdemain (argc=3, argv=0x7ffcf7b8b668) at ../main_x11.cpp:294
#38 0x00007f344cb49a40 in __libc_start_main (main=0x400790 <main(int, char**)>, argc=3, argv=0x7ffcf7b8b668, init=<optimized out>, fini=<optimized out>, rtld_fini=<optimized out>, stack_end=0x7ffcf7b8b658) at libc-start.c:289
#39 0x00000000004007c9 in _start ()

Reported using DrKonqi