This error occurs suddenly with different programs, so I guess it's a "general" KDE error. The error message is like this: Application: Program (Program), signal: Bus error Please take a look at the log for details. Reproducible: Sometimes LOG 1: Application: kwin (4.11.9) KDE Platform Version: 4.13.1 Qt Version: 4.8.6 Operating System: Linux 3.14.6-1-ARCH x86_64 Distribution (Platform): Archlinux Packages -- Information about the crash: <In detail, tell us what you were doing when the application crashed.> The crash can be reproduced sometimes. -- Backtrace: Application: KWin (kwin), signal: Bus error Using host libthread_db library "/usr/lib/libthread_db.so.1". [Current thread is 1 (Thread 0x7f353e7ad800 (LWP 27807))] Thread 2 (Thread 0x7f351965c700 (LWP 27994)): #0 0x00007f3537f1bb2f in pthread_cond_wait@@GLIBC_2.3.2 () from /usr/lib/libpthread.so.0 #1 0x00007f353d1cafab in ?? () from /usr/lib/libQtScript.so.4 #2 0x00007f353d1cafe9 in ?? () from /usr/lib/libQtScript.so.4 #3 0x00007f3537f17124 in start_thread () from /usr/lib/libpthread.so.0 #4 0x00007f353dfcb4bd in clone () from /usr/lib/libc.so.6 Thread 1 (Thread 0x7f353e7ad800 (LWP 27807)): [KCrash Handler] #5 0x00007f352d9f10b2 in ?? () from /usr/lib/libfontconfig.so.1 #6 0x00007f352d9f128b in ?? () from /usr/lib/libfontconfig.so.1 #7 0x00007f352d9f1c6d in FcFontMatch () from /usr/lib/libfontconfig.so.1 #8 0x00007f3537661b8f in QFontDatabase::load(QFontPrivate const*, int) () from /usr/lib/libQtGui.so.4 #9 0x00007f353763edb9 in QFontPrivate::engineForScript(int) const () from /usr/lib/libQtGui.so.4 #10 0x00007f3537652080 in QFontMetrics::height() const () from /usr/lib/libQtGui.so.4 #11 0x00007f35186a202f in ?? () from /usr/lib/kde4/kwin4_effect_builtins.so #12 0x00007f35382bf30a in QMetaObject::activate(QObject*, QMetaObject const*, int, void**) () from /usr/lib/libQtCore.so.4 #13 0x00007f353daaa261 in KWin::EffectsHandler::tabBoxAdded(int) () from /usr/lib/libkwineffects.so.1 #14 0x00007f353daaaa93 in ?? () from /usr/lib/libkwineffects.so.1 #15 0x00007f35382bf30a in QMetaObject::activate(QObject*, QMetaObject const*, int, void**) () from /usr/lib/libQtCore.so.4 #16 0x00007f353e3a7045 in ?? () from /usr/lib/libkdeinit4_kwin.so #17 0x00007f353e3ac165 in ?? () from /usr/lib/libkdeinit4_kwin.so #18 0x00007f35382bf30a in QMetaObject::activate(QObject*, QMetaObject const*, int, void**) () from /usr/lib/libQtCore.so.4 #19 0x00007f35382c34c1 in QObject::event(QEvent*) () from /usr/lib/libQtCore.so.4 #20 0x00007f353742df0c in QApplicationPrivate::notify_helper(QObject*, QEvent*) () from /usr/lib/libQtGui.so.4 #21 0x00007f353743448d in QApplication::notify(QObject*, QEvent*) () from /usr/lib/libQtGui.so.4 #22 0x00007f353cbfa63a in KApplication::notify(QObject*, QEvent*) () from /usr/lib/libkdeui.so.5 #23 0x00007f35382ab58d in QCoreApplication::notifyInternal(QObject*, QEvent*) () from /usr/lib/libQtCore.so.4 #24 0x00007f35382dad63 in ?? () from /usr/lib/libQtCore.so.4 #25 0x00007f35382db730 in QEventDispatcherUNIX::processEvents(QFlags<QEventLoop::ProcessEventsFlag>) () from /usr/lib/libQtCore.so.4 #26 0x00007f35374cb8d6 in ?? () from /usr/lib/libQtGui.so.4 #27 0x00007f35382aa15f in QEventLoop::processEvents(QFlags<QEventLoop::ProcessEventsFlag>) () from /usr/lib/libQtCore.so.4 #28 0x00007f35382aa455 in QEventLoop::exec(QFlags<QEventLoop::ProcessEventsFlag>) () from /usr/lib/libQtCore.so.4 #29 0x00007f35382af719 in QCoreApplication::exec() () from /usr/lib/libQtCore.so.4 #30 0x00007f353e30b946 in kdemain () from /usr/lib/libkdeinit4_kwin.so #31 0x00007f353df02000 in __libc_start_main () from /usr/lib/libc.so.6 #32 0x00000000004006fe in _start () Report to https://bugs.kde.org/ LOG 2: Application: Plasma Desktop Shell (plasma-desktop), signal: Bus error Using host libthread_db library "/usr/lib/libthread_db.so.1". [Current thread is 1 (Thread 0x7fc58d1c4780 (LWP 1470))] Thread 3 (Thread 0x7fc561afb700 (LWP 1480)): #0 0x00007fc58ba2df00 in __pthread_mutex_unlock_usercnt () from /usr/lib/libpthread.so.0 #1 0x00007fc5878ea751 in g_mutex_unlock () from /usr/lib/libglib-2.0.so.0 #2 0x00007fc5878a8400 in g_main_context_prepare () from /usr/lib/libglib-2.0.so.0 #3 0x00007fc5878a8c83 in ?? () from /usr/lib/libglib-2.0.so.0 #4 0x00007fc5878a8e6c in g_main_context_iteration () from /usr/lib/libglib-2.0.so.0 #5 0x00007fc58bdeb2c6 in QEventDispatcherGlib::processEvents(QFlags<QEventLoop::ProcessEventsFlag>) () from /usr/lib/libQtCore.so.4 #6 0x00007fc58bdbd15f in QEventLoop::processEvents(QFlags<QEventLoop::ProcessEventsFlag>) () from /usr/lib/libQtCore.so.4 #7 0x00007fc58bdbd455 in QEventLoop::exec(QFlags<QEventLoop::ProcessEventsFlag>) () from /usr/lib/libQtCore.so.4 #8 0x00007fc58bcb97ef in QThread::exec() () from /usr/lib/libQtCore.so.4 #9 0x00007fc58bd9e943 in ?? () from /usr/lib/libQtCore.so.4 #10 0x00007fc58bcbbebf in ?? () from /usr/lib/libQtCore.so.4 #11 0x00007fc58ba2a124 in start_thread () from /usr/lib/libpthread.so.0 #12 0x00007fc58a7a54bd in clone () from /usr/lib/libc.so.6 Thread 2 (Thread 0x7fc5537cd700 (LWP 1483)): #0 0x00007fc58ba2eb2f in pthread_cond_wait@@GLIBC_2.3.2 () from /usr/lib/libpthread.so.0 #1 0x00007fc57e92ffab in ?? () from /usr/lib/libQtScript.so.4 #2 0x00007fc57e92ffe9 in ?? () from /usr/lib/libQtScript.so.4 #3 0x00007fc58ba2a124 in start_thread () from /usr/lib/libpthread.so.0 #4 0x00007fc58a7a54bd in clone () from /usr/lib/libc.so.6 Thread 1 (Thread 0x7fc58d1c4780 (LWP 1470)): [KCrash Handler] #5 0x00007fc586d060b2 in ?? () from /usr/lib/libfontconfig.so.1 #6 0x00007fc586d0628b in ?? () from /usr/lib/libfontconfig.so.1 #7 0x00007fc586d06c6d in FcFontMatch () from /usr/lib/libfontconfig.so.1 #8 0x00007fc58b174b8f in QFontDatabase::load(QFontPrivate const*, int) () from /usr/lib/libQtGui.so.4 #9 0x00007fc58b151db9 in QFontPrivate::engineForScript(int) const () from /usr/lib/libQtGui.so.4 #10 0x00007fc58b187809 in QTextEngine::fontEngine(QScriptItem const&, QFixed*, QFixed*, QFixed*) const () from /usr/lib/libQtGui.so.4 #11 0x00007fc58b188183 in QTextEngine::shapeTextWithHarfbuzz(int) const () from /usr/lib/libQtGui.so.4 #12 0x00007fc58b189282 in QTextEngine::shapeText(int) const () from /usr/lib/libQtGui.so.4 #13 0x00007fc58b1895a5 in QTextEngine::shape(int) const () from /usr/lib/libQtGui.so.4 #14 0x00007fc58b19a84f in QTextLine::layout_helper(int) () from /usr/lib/libQtGui.so.4 #15 0x00007fc58b1d01ed in ?? () from /usr/lib/libQtGui.so.4 #16 0x00007fc58b1d7783 in ?? () from /usr/lib/libQtGui.so.4 #17 0x00007fc58b1d2e24 in ?? () from /usr/lib/libQtGui.so.4 #18 0x00007fc58b1d391c in ?? () from /usr/lib/libQtGui.so.4 #19 0x00007fc58b1d5db1 in ?? () from /usr/lib/libQtGui.so.4 #20 0x00007fc58b1d67ed in ?? () from /usr/lib/libQtGui.so.4 #21 0x00007fc58b1d7d28 in ?? () from /usr/lib/libQtGui.so.4 #22 0x00007fc58b1d611d in ?? () from /usr/lib/libQtGui.so.4 #23 0x00007fc58b1d67ed in ?? () from /usr/lib/libQtGui.so.4 #24 0x00007fc58b1d92a0 in ?? () from /usr/lib/libQtGui.so.4 #25 0x00007fc58b1d9568 in ?? () from /usr/lib/libQtGui.so.4 #26 0x00007fc58b1d96fd in ?? () from /usr/lib/libQtGui.so.4 #27 0x00007fc58b1da490 in ?? () from /usr/lib/libQtGui.so.4 #28 0x00007fc58b1b7db1 in ?? () from /usr/lib/libQtGui.so.4 #29 0x00007fc58b1ab2b0 in QTextDocument::setHtml(QString const&) () from /usr/lib/libQtGui.so.4 #30 0x00007fc58b3310b5 in ?? () from /usr/lib/libQtGui.so.4 #31 0x00007fc58b3311dd in ?? () from /usr/lib/libQtGui.so.4 #32 0x00007fc58b33274f in ?? () from /usr/lib/libQtGui.so.4 #33 0x00007fc58b332c47 in QLabel::minimumSizeHint() const () from /usr/lib/libQtGui.so.4 #34 0x00007fc58b50802d in QGraphicsProxyWidget::sizeHint(Qt::SizeHint, QSizeF const&) const () from /usr/lib/libQtGui.so.4 #35 0x00007fc581201d5c in Plasma::Label::sizeHint(Qt::SizeHint, QSizeF const&) const () from /usr/lib/libplasma.so.3 #36 0x00007fc58b501031 in ?? () from /usr/lib/libQtGui.so.4 #37 0x00007fc58b5018ea in QGraphicsLayoutItem::effectiveSizeHint(Qt::SizeHint, QSizeF const&) const () from /usr/lib/libQtGui.so.4 #38 0x00007fc58b54591a in ?? () from /usr/lib/libQtGui.so.4 #39 0x00007fc58b549803 in ?? () from /usr/lib/libQtGui.so.4 #40 0x00007fc58b54a322 in ?? () from /usr/lib/libQtGui.so.4 #41 0x00007fc58b54a670 in ?? () from /usr/lib/libQtGui.so.4 #42 0x00007fc58b4d83b7 in QGraphicsGridLayout::sizeHint(Qt::SizeHint, QSizeF const&) const () from /usr/lib/libQtGui.so.4 #43 0x00007fc58b50108c in ?? () from /usr/lib/libQtGui.so.4 #44 0x00007fc58b5018ea in QGraphicsLayoutItem::effectiveSizeHint(Qt::SizeHint, QSizeF const&) const () from /usr/lib/libQtGui.so.4 #45 0x00007fc58b53c739 in QGraphicsWidget::sizeHint(Qt::SizeHint, QSizeF const&) const () from /usr/lib/libQtGui.so.4 #46 0x00007fc58b50108c in ?? () from /usr/lib/libQtGui.so.4 #47 0x00007fc58b5018ea in QGraphicsLayoutItem::effectiveSizeHint(Qt::SizeHint, QSizeF const&) const () from /usr/lib/libQtGui.so.4 #48 0x00007fc58b54591a in ?? () from /usr/lib/libQtGui.so.4 #49 0x00007fc58b549803 in ?? () from /usr/lib/libQtGui.so.4 #50 0x00007fc58b54a322 in ?? () from /usr/lib/libQtGui.so.4 #51 0x00007fc58b54ab51 in ?? () from /usr/lib/libQtGui.so.4 #52 0x00007fc58b54b0d0 in ?? () from /usr/lib/libQtGui.so.4 #53 0x00007fc58b502c0d in QGraphicsLinearLayout::setGeometry(QRectF const&) () from /usr/lib/libQtGui.so.4 #54 0x00007fc58b5000c3 in QGraphicsLayout::widgetEvent(QEvent*) () from /usr/lib/libQtGui.so.4 #55 0x00007fc58b53c9cb in QGraphicsWidget::event(QEvent*) () from /usr/lib/libQtGui.so.4 #56 0x00007fc58af40f0c in QApplicationPrivate::notify_helper(QObject*, QEvent*) () from /usr/lib/libQtGui.so.4 #57 0x00007fc58af4748d in QApplication::notify(QObject*, QEvent*) () from /usr/lib/libQtGui.so.4 #58 0x00007fc58cb9e63a in KApplication::notify(QObject*, QEvent*) () from /usr/lib/libkdeui.so.5 #59 0x00007fc58bdbe58d in QCoreApplication::notifyInternal(QObject*, QEvent*) () from /usr/lib/libQtCore.so.4 #60 0x00007fc58b540096 in QGraphicsWidget::setGeometry(QRectF const&) () from /usr/lib/libQtGui.so.4 #61 0x00007fc58b53ce79 in QGraphicsWidget::resize(QSizeF const&) () from /usr/lib/libQtGui.so.4 #62 0x00007fc58b53d685 in QGraphicsWidget::adjustSize() () from /usr/lib/libQtGui.so.4 #63 0x00007fc58b540c0f in QGraphicsWidget::itemChange(QGraphicsItem::GraphicsItemChange, QVariant const&) () from /usr/lib/libQtGui.so.4 #64 0x00007fc58b4ede05 in QGraphicsItemPrivate::setVisibleHelper(bool, bool, bool) () from /usr/lib/libQtGui.so.4 #65 0x00007fc581226ab2 in Plasma::TabBar::setCurrentIndex(int) () from /usr/lib/libplasma.so.3 #66 0x00007fc4cd1e6142 in ?? () from /usr/lib/kde4/plasma_applet_networkmanagement.so #67 0x00007fc58bdd230a in QMetaObject::activate(QObject*, QMetaObject const*, int, void**) () from /usr/lib/libQtCore.so.4 #68 0x00007fc5811fd480 in Plasma::IconWidget::mouseReleaseEvent(QGraphicsSceneMouseEvent*) () from /usr/lib/libplasma.so.3 #69 0x00007fc58b4e6b62 in QGraphicsItem::sceneEvent(QEvent*) () from /usr/lib/libQtGui.so.4 #70 0x00007fc58b50db7f in ?? () from /usr/lib/libQtGui.so.4 #71 0x00007fc58b5167cf in QGraphicsScene::mouseReleaseEvent(QGraphicsSceneMouseEvent*) () from /usr/lib/libQtGui.so.4 #72 0x00007fc58b5226f0 in QGraphicsScene::event(QEvent*) () from /usr/lib/libQtGui.so.4 #73 0x00007fc58af40f0c in QApplicationPrivate::notify_helper(QObject*, QEvent*) () from /usr/lib/libQtGui.so.4 #74 0x00007fc58af4748d in QApplication::notify(QObject*, QEvent*) () from /usr/lib/libQtGui.so.4 #75 0x00007fc58cb9e63a in KApplication::notify(QObject*, QEvent*) () from /usr/lib/libkdeui.so.5 #76 0x00007fc58bdbe58d in QCoreApplication::notifyInternal(QObject*, QEvent*) () from /usr/lib/libQtCore.so.4 #77 0x00007fc58b539347 in QGraphicsView::mouseReleaseEvent(QMouseEvent*) () from /usr/lib/libQtGui.so.4 #78 0x00007fc58af9044a in QWidget::event(QEvent*) () from /usr/lib/libQtGui.so.4 #79 0x00007fc58b32e1de in QFrame::event(QEvent*) () from /usr/lib/libQtGui.so.4 #80 0x00007fc58b539d69 in QGraphicsView::viewportEvent(QEvent*) () from /usr/lib/libQtGui.so.4 #81 0x00007fc58bdbe6f6 in QCoreApplicationPrivate::sendThroughObjectEventFilters(QObject*, QEvent*) () from /usr/lib/libQtCore.so.4 #82 0x00007fc58af40eec in QApplicationPrivate::notify_helper(QObject*, QEvent*) () from /usr/lib/libQtGui.so.4 #83 0x00007fc58af475ca in QApplication::notify(QObject*, QEvent*) () from /usr/lib/libQtGui.so.4 #84 0x00007fc58cb9e63a in KApplication::notify(QObject*, QEvent*) () from /usr/lib/libkdeui.so.5 #85 0x00007fc58bdbe58d in QCoreApplication::notifyInternal(QObject*, QEvent*) () from /usr/lib/libQtCore.so.4 #86 0x00007fc58af46dc3 in QApplicationPrivate::sendMouseEvent(QWidget*, QMouseEvent*, QWidget*, QWidget*, QWidget**, QPointer<QWidget>&, bool) () from /usr/lib/libQtGui.so.4 #87 0x00007fc58afb895b in ?? () from /usr/lib/libQtGui.so.4 #88 0x00007fc58afb73cc in QApplication::x11ProcessEvent(_XEvent*) () from /usr/lib/libQtGui.so.4 #89 0x00007fc58afddf02 in ?? () from /usr/lib/libQtGui.so.4 #90 0x00007fc5878a8b84 in g_main_context_dispatch () from /usr/lib/libglib-2.0.so.0 #91 0x00007fc5878a8dc8 in ?? () from /usr/lib/libglib-2.0.so.0 #92 0x00007fc5878a8e6c in g_main_context_iteration () from /usr/lib/libglib-2.0.so.0 #93 0x00007fc58bdeb2a5 in QEventDispatcherGlib::processEvents(QFlags<QEventLoop::ProcessEventsFlag>) () from /usr/lib/libQtCore.so.4 #94 0x00007fc58afddfb6 in ?? () from /usr/lib/libQtGui.so.4 #95 0x00007fc58bdbd15f in QEventLoop::processEvents(QFlags<QEventLoop::ProcessEventsFlag>) () from /usr/lib/libQtCore.so.4 #96 0x00007fc58bdbd455 in QEventLoop::exec(QFlags<QEventLoop::ProcessEventsFlag>) () from /usr/lib/libQtCore.so.4 #97 0x00007fc58bdc2719 in QCoreApplication::exec() () from /usr/lib/libQtCore.so.4 #98 0x00007fc576fff62c in kdemain () from /usr/lib/libkdeinit4_plasma-desktop.so #99 0x00000000004080e6 in _start ()
Crash is in libfontconfig.