Application: kwin_x11 (5.4.2)

Qt Version: 5.4.2
Operating System: Linux 4.2.0-35-generic x86_64
Distribution: Ubuntu 15.10

-- Information about the crash:
- What I was doing when the application crashed:
running kde in Xvfb launched by chrome-remote-desktop, Power Management disabled, connection is successful but a dialog is presented "Kwin is unstable.... you can choose another window manager", however only kwin_x11 is offered in the dropdown. 

Kde runs correctly in a hardware display, but not in a frame buffer.

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".
[KCrash Handler]
#6  xcb_setup_vendor_end (R=R@entry=0x0) at xproto.c:869
#7  0x00007f2496ad2419 in xcb_setup_pixmap_formats_iterator (R=R@entry=0x0) at xproto.c:892
#8  0x00007f2496ad2459 in xcb_setup_roots_iterator (R=R@entry=0x0) at xproto.c:909
#9  0x00007f2497d8d22d in NETRootInfo::NETRootInfo (this=0x180eab0, connection=<optimized out>, supportWindow=4294967295, wmName=0x7f24985dfc70 "KWin", properties=..., windowTypes=..., states=..., properties2=..., actions=..., screen=0, doActivate=true) at ../../src/platforms/xcb/netwm.cpp:470
#10 0x00007f2498493429 in KWin::RootInfo::RootInfo (this=0x180eab0, w=4294967295, name=0x7f24985dfc70 "KWin", properties=..., types=..., states=..., properties2=..., actions=..., scr=0) at ../netinfo.cpp:140
#11 0x00007f249849365e in KWin::RootInfo::create () at ../netinfo.cpp:125
#12 0x00007f2498464a09 in KWin::Workspace::init (this=this@entry=0x16da100) at ../workspace.cpp:256
#13 0x00007f2498466417 in KWin::Workspace::Workspace (this=0x16da100, sessionKey=...) at ../workspace.cpp:223
#14 0x00007f24984a0bf0 in KWin::Application::createWorkspace (this=this@entry=0x7ffcada06680) at ../main.cpp:373
#15 0x00007f2498c38f3c in KWin::ApplicationX11::<lambda()>::operator() (__closure=<synthetic pointer>) at ../main_x11.cpp:178
#16 QtPrivate::FunctorCall<QtPrivate::IndexesList<>, QtPrivate::List<>, void, KWin::ApplicationX11::performStartup()::<lambda()> >::call (arg=<optimized out>, f=...) at /usr/include/x86_64-linux-gnu/qt5/QtCore/qobjectdefs_impl.h:494
#17 QtPrivate::Functor<KWin::ApplicationX11::performStartup()::<lambda()>, 0>::call<QtPrivate::List<>, void> (arg=<optimized out>, f=...) at /usr/include/x86_64-linux-gnu/qt5/QtCore/qobjectdefs_impl.h:551
#18 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
#19 0x00007f2496f97617 in QtPrivate::QSlotObjectBase::call (a=0x7ffcada05e50, r=0x164bb90, this=<optimized out>) at ../../include/QtCore/../../src/corelib/kernel/qobject_impl.h:124
#20 QMetaObject::activate (sender=0x164bb90, signalOffset=<optimized out>, local_signal_index=local_signal_index@entry=1, argv=argv@entry=0x0) at kernel/qobject.cpp:3702
#21 0x00007f2496f97f87 in QMetaObject::activate (sender=<optimized out>, m=m@entry=0x7f2497fa1b20 <KSelectionOwner::staticMetaObject>, local_signal_index=local_signal_index@entry=1, argv=argv@entry=0x0) at kernel/qobject.cpp:3582
#22 0x00007f2497d94663 in KSelectionOwner::claimedOwnership (this=<optimized out>) at moc_kselectionowner.cpp:150
#23 0x00007f2497d8034b in KSelectionOwner::Private::claimSucceeded (this=0x16626e0) at ../../src/platforms/xcb/kselectionowner.cpp:206
#24 0x00007f2497d80ac1 in KSelectionOwner::filterEvent (this=0x164bb90, ev_P=<optimized out>) at ../../src/platforms/xcb/kselectionowner.cpp:424
#25 0x00007f2496f638ef in QAbstractEventDispatcher::filterNativeEvent (this=this@entry=0x1635340, eventType=..., message=message@entry=0x7f247c001a80, result=result@entry=0x7ffcada05f98) at kernel/qabstracteventdispatcher.cpp:460
#26 0x00007f2482aeb35e in QXcbConnection::handleXcbEvent (this=this@entry=0x15fa740, event=event@entry=0x7f247c001a80) at qxcbconnection.cpp:863
#27 0x00007f2482aec3b3 in QXcbConnection::processXcbEvents (this=0x15fa740) at qxcbconnection.cpp:1303
#28 0x00007f2496f98651 in QObject::event (this=0x15fa740, e=<optimized out>) at kernel/qobject.cpp:1245
#29 0x00007f2497834b8c in QApplicationPrivate::notify_helper (this=this@entry=0x15f3650, receiver=receiver@entry=0x15fa740, e=e@entry=0x7f247c0012f0) at kernel/qapplication.cpp:3720
#30 0x00007f249783a230 in QApplication::notify (this=0x7ffcada06680, receiver=0x15fa740, e=0x7f247c0012f0) at kernel/qapplication.cpp:3503
#31 0x00007f2496f66f1b in QCoreApplication::notifyInternal (this=0x7ffcada06680, receiver=0x15fa740, event=event@entry=0x7f247c0012f0) at kernel/qcoreapplication.cpp:935
#32 0x00007f2496f69057 in QCoreApplication::sendEvent (event=0x7f247c0012f0, receiver=<optimized out>) at ../../include/QtCore/../../src/corelib/kernel/qcoreapplication.h:228
#33 QCoreApplicationPrivate::sendPostedEvents (receiver=receiver@entry=0x0, event_type=event_type@entry=0, data=0x15e40e0) at kernel/qcoreapplication.cpp:1552
#34 0x00007f2496fbb802 in QEventDispatcherUNIX::processEvents (this=0x1635340, flags=flags@entry=...) at kernel/qeventdispatcher_unix.cpp:579
#35 0x00007f2482b4005d in QUnixEventDispatcherQPA::processEvents (this=<optimized out>, flags=...) at eventdispatchers/qunixeventdispatcher.cpp:62
#36 0x00007f2496f6475a in QEventLoop::exec (this=this@entry=0x7ffcada065a0, flags=..., flags@entry=...) at kernel/qeventloop.cpp:204
#37 0x00007f2496f6c2cc in QCoreApplication::exec () at kernel/qcoreapplication.cpp:1188
#38 0x00007f249728100c in QGuiApplication::exec () at kernel/qguiapplication.cpp:1510
#39 0x00007f2497831025 in QApplication::exec () at kernel/qapplication.cpp:2956
#40 0x00007f2498c3a4c4 in kdemain (argc=3, argv=0x7ffcada067e8) at ../main_x11.cpp:303
#41 0x00007f249888ba40 in __libc_start_main (main=0x4007a0 <main(int, char**)>, argc=3, argv=0x7ffcada067e8, init=<optimized out>, fini=<optimized out>, rtld_fini=<optimized out>, stack_end=0x7ffcada067d8) at libc-start.c:289
#42 0x00000000004007d9 in _start ()

Possible duplicates by query: bug 353139, bug 351165, bug 351046, bug 350237, bug 349953.

Reported using DrKonqi