i have launched Plasma waylaid session from dddm, fired console and chromium, then pressed Alt+Tab and kwin crashed with the following backtrace (obtained by connecting with gdb in remote ssh session): #0 0x00007faf781879f8 in QOpenGLContext::format() const () from /usr/lib/x86_64-linux-gnu/libQt5Gui.so.5 #1 0x00007faf7982b9c3 in QSGBatchRenderer::Renderer::Renderer(QSGRenderContext*) () from /usr/lib/x86_64-linux-gnu/libQt5Quick.so.5 #2 0x00007faf79849ed1 in QSGRenderContext::createRenderer() () from /usr/lib/x86_64-linux-gnu/libQt5Quick.so.5 #3 0x00007faf79892d48 in QQuickWindowPrivate::syncSceneGraph() () from /usr/lib/x86_64-linux-gnu/libQt5Quick.so.5 #4 0x00007faf7985f908 in ?? () from /usr/lib/x86_64-linux-gnu/libQt5Quick.so.5 #5 0x00007faf79860bc8 in ?? () from /usr/lib/x86_64-linux-gnu/libQt5Quick.so.5 #6 0x00007faf78158865 in QWindow::event(QEvent*) () from /usr/lib/x86_64-linux-gnu/libQt5Gui.so.5 #7 0x00007faf7989ccb5 in QQuickWindow::event(QEvent*) () from /usr/lib/x86_64-linux-gnu/libQt5Quick.so.5 #8 0x00007faec207428b in PlasmaQuick::Dialog::event(QEvent*) () from /usr/lib/x86_64-linux-gnu/libKF5PlasmaQuick.so.5 #9 0x00007faf7e620b2c in QApplicationPrivate::notify_helper(QObject*, QEvent*) () from /usr/lib/x86_64-linux-gnu/libQt5Widgets.so.5 #10 0x00007faf7e6282e1 in QApplication::notify(QObject*, QEvent*) () from /usr/lib/x86_64-linux-gnu/libQt5Widgets.so.5 #11 0x00007faf7e272090 in QCoreApplication::notifyInternal2(QObject*, QEvent*) () from /usr/lib/x86_64-linux-gnu/libQt5Core.so.5 #12 0x00007faf7814daed in QGuiApplicationPrivate::processExposeEvent(QWindowSystemInterfacePrivate::ExposeEvent*) () from /usr/lib/x86_64-linux-gnu/libQt5Gui.so.5 #13 0x00007faf7814e6fd in QGuiApplicationPrivate::processWindowSystemEvent(QWindowSystemInterfacePrivate::WindowSystemEvent*) () from /usr/lib/x86_64-linux-gnu/libQt5Gui.so.5 #14 0x00007faf7812c61b in QWindowSystemInterface::sendWindowSystemEvents(QFlags<QEventLoop::ProcessEventsFlag>) () from /usr/lib/x86_64-linux-gnu/libQt5Gui.so.5 #15 0x00007faf7812d1e0 in QWindowSystemInterface::flushWindowSystemEvents(QFlags<QEventLoop::ProcessEventsFlag>) () from /usr/lib/x86_64-linux-gnu/libQt5Gui.so.5 #16 0x00007faf7813bf08 in QPlatformWindow::setVisible(bool) () from /usr/lib/x86_64-linux-gnu/libQt5Gui.so.5 #17 0x00007faf7815632b in QWindow::setVisible(bool) () from /usr/lib/x86_64-linux-gnu/libQt5Gui.so.5 #18 0x00007faec20707a4 in PlasmaQuick::Dialog::setVisible(bool) () from /usr/lib/x86_64-linux-gnu/libKF5PlasmaQuick.so.5 #19 0x00007faec2073ac8 in ?? () from /usr/lib/x86_64-linux-gnu/libKF5PlasmaQuick.so.5 #20 0x00007faec20751cb in PlasmaQuick::Dialog::qt_metacall(QMetaObject::Call, int, void**) () from /usr/lib/x86_64-linux-gnu/libKF5PlasmaQuick.so.5 #21 0x00007faf79318ee2 in QQmlPropertyPrivate::write(QObject*, QQmlPropertyData const&, QVariant const&, QQmlContextData*, QFlags<QQmlPropertyPrivate::WriteFlag>) () from /usr/lib/x86_64-linux-gnu/libQt5Qml.so.5 #22 0x00007faf7931a623 in QQmlPropertyPrivate::writeValueProperty(QObject*, QQmlPropertyData const&, QVariant const&, QQmlContextData*, QFlags<QQmlPropertyPrivate::WriteFlag>) () from /usr/lib/x86_64-linux-gnu/libQt5Qml.so.5 #23 0x00007faf79386e45 in QQmlBinding::write(QQmlPropertyData const&, QV4::Value const&, bool, QFlags<QQmlPropertyPrivate::WriteFlag>) () from /usr/lib/x86_64-linux-gnu/libQt5Qml.so.5 #24 0x00007faf79387eb7 in QQmlBinding::update(QFlags<QQmlPropertyPrivate::WriteFlag>) () from /usr/lib/x86_64-linux-gnu/libQt5Qml.so.5 #25 0x00007faf7938891e in QQmlBinding::refresh() () from /usr/lib/x86_64-linux-gnu/libQt5Qml.so.5 #26 0x00007faf7935d884 in QQmlNotifier::emitNotify(QQmlNotifierEndpoint*, void**) () from /usr/lib/x86_64-linux-gnu/libQt5Qml.so.5 #27 0x00007faf793085ac in QQmlData::signalEmitted(QAbstractDeclarativeData*, QObject*, int, void**) () from /usr/lib/x86_64-linux-gnu/libQt5Qml.so.5 #28 0x00007faf7e29e3a4 in QMetaObject::activate(QObject*, int, int, void**) () from /usr/lib/x86_64-linux-gnu/libQt5Core.so.5 #29 0x00007faf7fb7376d in ?? () from /usr/lib/x86_64-linux-gnu/libkwin.so.5 #30 0x00007faf7fb739e9 in ?? () from /usr/lib/x86_64-linux-gnu/libkwin.so.5 #31 0x00007faf7e29dc89 in QMetaObject::activate(QObject*, int, int, void**) () from /usr/lib/x86_64-linux-gnu/libQt5Core.so.5 #32 0x00007faf7e2aa608 in QTimer::timerEvent(QTimerEvent*) () from /usr/lib/x86_64-linux-gnu/libQt5Core.so.5 #33 0x00007faf7e29eaf3 in QObject::event(QEvent*) () from /usr/lib/x86_64-linux-gnu/libQt5Core.so.5 #34 0x00007faf7e620b2c in QApplicationPrivate::notify_helper(QObject*, QEvent*) () from /usr/lib/x86_64-linux-gnu/libQt5Widgets.so.5 #35 0x00007faf7e6282e1 in QApplication::notify(QObject*, QEvent*) () from /usr/lib/x86_64-linux-gnu/libQt5Widgets.so.5 #36 0x00007faf7e272090 in QCoreApplication::notifyInternal2(QObject*, QEvent*) () from /usr/lib/x86_64-linux-gnu/libQt5Core.so.5 #37 0x00007faf7e2c567e in QTimerInfoList::activateTimers() () from /usr/lib/x86_64-linux-gnu/libQt5Core.so.5 #38 0x00007faf7e2c358a in QEventDispatcherUNIX::processEvents(QFlags<QEventLoop::ProcessEventsFlag>) () from /usr/lib/x86_64-linux-gnu/libQt5Core.so.5 #39 0x00007faf6849486d in ?? () from /usr/lib/x86_64-linux-gnu/qt5/plugins/platforms/KWinQpaPlugin.so #40 0x00007faf7e27007a in QEventLoop::exec(QFlags<QEventLoop::ProcessEventsFlag>) () from /usr/lib/x86_64-linux-gnu/libQt5Core.so.5 #41 0x00007faf7e2787ec in QCoreApplication::exec() () from /usr/lib/x86_64-linux-gnu/libQt5Core.so.5 #42 0x000055caa7b2f920 in ?? () #43 0x00007faf7d6c12b1 in __libc_start_main (main=0x55caa7b2df60, argc=4, argv=0x7ffc5d8bf508, init=<optimized out>, fini=<optimized out>, rtld_fini=<optimized out>, stack_end=0x7ffc5d8bf4f8) at ../csu/libc-start.c:291 #44 0x000055caa7b3006a in _start ()
note that i get this crash even when no windows were open. for this to happen i had to press Alt+Tab several times in a row, and this is what happened when i started pressing alt+Tab: [New Thread 0x7f1dc2f17700 (LWP 1527)] [New Thread 0x7f1dc2716700 (LWP 1528)] [New Thread 0x7f1dc1f15700 (LWP 1529)] [New Thread 0x7f1dc1714700 (LWP 1530)] Thread 1 "kwin_wayland" received signal SIGSEGV, Segmentation fault. 0x00007f1e7ca3b9f8 in QOpenGLContext::format() const () from /usr/lib/x86_64-linux-gnu/libQt5Gui.so.5
Unfortunately the backtrace is lacking debug symbols. We don't see where it crashes at all.
the crash happens because the pointer to QOpenGLContext is zero. #0 QOpenGLContext::format (this=0x0) at kernel/qopenglcontext.cpp:1109 #1 0x00007f86a9ee3e86 in QSGBatchRenderer::Renderer::Renderer (this=0x5597b03a2040, ctx=0x5597afc01b40) at scenegraph/coreapi/qsgbatchrenderer.cpp:816 #2 0x00007f86a9f015b1 in QSGRenderContext::createRenderer (this=0x5597afc01b40) at scenegraph/qsgcontext.cpp:775 #3 0x00007f86a9f47a1c in QQuickWindowPrivate::syncSceneGraph (this=this@entry=0x5597afcba350) at items/qquickwindow.cpp:415 #4 0x00007f86a9f16753 in QSGGuiThreadRenderLoop::renderWindow (this=this@entry=0x5597afcea910, window=<optimized out>) at scenegraph/qsgrenderloop.cpp:391 #5 0x00007f86a9f17990 in QSGGuiThreadRenderLoop::exposureChanged (this=0x5597afcea910, window=<optimized out>) at scenegraph/qsgrenderloop.cpp:442 #6 0x00007f86a883fdab in QWindow::event (this=this@entry=0x5597b00eec70, ev=ev@entry=0x7ffca3627440) at kernel/qwindow.cpp:2133 #7 0x00007f86a9f510c3 in QQuickWindow::event (this=0x5597b00eec70, e=0x7ffca3627440) at items/qquickwindow.cpp:1518 #8 0x00007f8674a9a28b in PlasmaQuick::Dialog::event(QEvent*) () from /usr/lib/x86_64-linux-gnu/libKF5PlasmaQuick.so.5 #9 0x00007f86aecb0fec in QApplicationPrivate::notify_helper (this=<optimized out>, receiver=0x5597b00eec70, e=0x7ffca3627440) at kernel/qapplication.cpp:3799 #10 0x00007f86aecb8171 in QApplication::notify (this=0x7ffca3629d90, receiver=0x5597b00eec70, e=0x7ffca3627440) at kernel/qapplication.cpp:3556 #11 0x00007f86ae907578 in QCoreApplication::notifyInternal2 (receiver=receiver@entry=0x5597b00eec70, event=event@entry=0x7ffca3627440) at kernel/qcoreapplication.cpp:988
Could you please provide the output of: qdbus org.kde.KWin /KWin supportInformation from within the Wayland session? Can you try some other QtQuick dialogs? E.g. the outline on quick maximization or the close button in Present Windows? I would assume they all result in a crash?
Waiting for response for further investigation.
Dear Bug Submitter, This bug has been in NEEDSINFO status with no change for at least 15 days. Please provide the requested information as soon as possible and set the bug status as REPORTED. Due to regular bug tracker maintenance, if the bug is still in NEEDSINFO status with no change in 30 days, the bug will be closed as RESOLVED > WORKSFORME due to lack of needed information. For more information about our bug triaging procedures please read the wiki located here: https://community.kde.org/Guidelines_and_HOWTOs/Bug_triaging If you have already provided the requested information, please set the bug status as REPORTED so that the KDE team knows that the bug is ready to be confirmed. Thank you for helping us make KDE software even better for everyone!
Dear Bug Submitter, This bug has been in NEEDSINFO status with no change for at least 30 days. The bug is now closed as RESOLVED > WORKSFORME due to lack of needed information. For more information about our bug triaging procedures please read the wiki located here: https://community.kde.org/Guidelines_and_HOWTOs/Bug_triaging Thank you for helping us make KDE software even better for everyone!