plasma-discover stalled

Since about a month plasma-discover, RStudio, and a java script (cafetran) do no longer launch. Here is the report for plasma-discover. The "segment fault" always shows.
What is the problem?
Thanks,
R

Application: Discover (plasma-discover), signal: Segmentation fault
Using host libthread_db library "/lib/x86_64-linux-gnu/libthread_db.so.1".
[Current thread is 1 (Thread 0x7fe607737f40 (LWP 80787))]

Thread 8 (Thread 0x7fe5ef2cf700 (LWP 80794)):
#0 futex_wait_cancelable (private=<optimized out>, expected=0, futex_word=0x7fe6000046c8) at ../sysdeps/nptl/futex-internal.h:183
#1 __pthread_cond_wait_common (abstime=0x0, clockid=0, mutex=0x7fe600004678, cond=0x7fe6000046a0) at pthread_cond_wait.c:508
#2 __pthread_cond_wait (cond=0x7fe6000046a0, mutex=0x7fe600004678) at pthread_cond_wait.c:638
#3 0x00007fe5f6253b5b in () at /usr/lib/x86_64-linux-gnu/dri/r300_dri.so
#4 0x00007fe5f625375b in () at /usr/lib/x86_64-linux-gnu/dri/r300_dri.so
#5 0x00007fe60accd609 in start_thread (arg=<optimized out>) at pthread_create.c:477
#6 0x00007fe60b94e293 in clone () at ../sysdeps/unix/sysv/linux/x86_64/clone.S:95

Thread 7 (Thread 0x7fe5efad0700 (LWP 80793)):
#0 futex_wait_cancelable (private=<optimized out>, expected=0, futex_word=0x7fe6000046c8) at ../sysdeps/nptl/futex-internal.h:183
#1 __pthread_cond_wait_common (abstime=0x0, clockid=0, mutex=0x7fe600004678, cond=0x7fe6000046a0) at pthread_cond_wait.c:508
#2 __pthread_cond_wait (cond=0x7fe6000046a0, mutex=0x7fe600004678) at pthread_cond_wait.c:638
#3 0x00007fe5f6253b5b in () at /usr/lib/x86_64-linux-gnu/dri/r300_dri.so
#4 0x00007fe5f625375b in () at /usr/lib/x86_64-linux-gnu/dri/r300_dri.so
#5 0x00007fe60accd609 in start_thread (arg=<optimized out>) at pthread_create.c:477
#6 0x00007fe60b94e293 in clone () at ../sysdeps/unix/sysv/linux/x86_64/clone.S:95

Thread 6 (Thread 0x7fe5f02d1700 (LWP 80792)):
#0 futex_wait_cancelable (private=<optimized out>, expected=0, futex_word=0x7fe6000046c8) at ../sysdeps/nptl/futex-internal.h:183
#1 __pthread_cond_wait_common (abstime=0x0, clockid=0, mutex=0x7fe600004678, cond=0x7fe6000046a0) at pthread_cond_wait.c:508
#2 __pthread_cond_wait (cond=0x7fe6000046a0, mutex=0x7fe600004678) at pthread_cond_wait.c:638
#3 0x00007fe5f6253b5b in () at /usr/lib/x86_64-linux-gnu/dri/r300_dri.so
#4 0x00007fe5f625375b in () at /usr/lib/x86_64-linux-gnu/dri/r300_dri.so
#5 0x00007fe60accd609 in start_thread (arg=<optimized out>) at pthread_create.c:477
#6 0x00007fe60b94e293 in clone () at ../sysdeps/unix/sysv/linux/x86_64/clone.S:95

Thread 5 (Thread 0x7fe5f0ad2700 (LWP 80791)):
#0 futex_wait_cancelable (private=<optimized out>, expected=0, futex_word=0x7fe6000046c8) at ../sysdeps/nptl/futex-internal.h:183
#1 __pthread_cond_wait_common (abstime=0x0, clockid=0, mutex=0x7fe600004678, cond=0x7fe6000046a0) at pthread_cond_wait.c:508
#2 __pthread_cond_wait (cond=0x7fe6000046a0, mutex=0x7fe600004678) at pthread_cond_wait.c:638
#3 0x00007fe5f6253b5b in () at /usr/lib/x86_64-linux-gnu/dri/r300_dri.so
#4 0x00007fe5f625375b in () at /usr/lib/x86_64-linux-gnu/dri/r300_dri.so
#5 0x00007fe60accd609 in start_thread (arg=<optimized out>) at pthread_create.c:477
#6 0x00007fe60b94e293 in clone () at ../sysdeps/unix/sysv/linux/x86_64/clone.S:95

Thread 4 (Thread 0x7fe60522e700 (LWP 80790)):
#0 0x00007fe60a40c0f2 in () at /lib/x86_64-linux-gnu/libglib-2.0.so.0
#1 0x00007fe60a40dadf in g_main_context_check () at /lib/x86_64-linux-gnu/libglib-2.0.so.0
#2 0x00007fe60a40e132 in () at /lib/x86_64-linux-gnu/libglib-2.0.so.0
#3 0x00007fe60a40e2c3 in g_main_context_iteration () at /lib/x86_64-linux-gnu/libglib-2.0.so.0
#4 0x00007fe60bedf583 in QEventDispatcherGlib::processEvents(QFlags<QEventLoop::ProcessEventsFlag>) () at /lib/x86_64-linux-gnu/libQt5Core.so.5
#5 0x00007fe60be864db in QEventLoop::exec(QFlags<QEventLoop::ProcessEventsFlag>) () at /lib/x86_64-linux-gnu/libQt5Core.so.5
#6 0x00007fe60bcbe785 in QThread::exec() () at /lib/x86_64-linux-gnu/libQt5Core.so.5
#7 0x00007fe60c53b1a9 in () at /lib/x86_64-linux-gnu/libQt5Qml.so.5
#8 0x00007fe60bcbf9d2 in () at /lib/x86_64-linux-gnu/libQt5Core.so.5
#9 0x00007fe60accd609 in start_thread (arg=<optimized out>) at pthread_create.c:477
#10 0x00007fe60b94e293 in clone () at ../sysdeps/unix/sysv/linux/x86_64/clone.S:95

Thread 3 (Thread 0x7fe605a2f700 (LWP 80789)):
#0 0x00007fe60b941aff in __GI___poll (fds=0x7fe5f80029e0, nfds=1, timeout=-1) at ../sysdeps/unix/sysv/linux/poll.c:29
#1 0x00007fe60a40e18e in () at /lib/x86_64-linux-gnu/libglib-2.0.so.0
#2 0x00007fe60a40e2c3 in g_main_context_iteration () at /lib/x86_64-linux-gnu/libglib-2.0.so.0
#3 0x00007fe60bedf583 in QEventDispatcherGlib::processEvents(QFlags<QEventLoop::ProcessEventsFlag>) () at /lib/x86_64-linux-gnu/libQt5Core.so.5
#4 0x00007fe60be864db in QEventLoop::exec(QFlags<QEventLoop::ProcessEventsFlag>) () at /lib/x86_64-linux-gnu/libQt5Core.so.5
#5 0x00007fe60bcbe785 in QThread::exec() () at /lib/x86_64-linux-gnu/libQt5Core.so.5
#6 0x00007fe60d373efa in () at /lib/x86_64-linux-gnu/libQt5DBus.so.5
#7 0x00007fe60bcbf9d2 in () at /lib/x86_64-linux-gnu/libQt5Core.so.5
#8 0x00007fe60accd609 in start_thread (arg=<optimized out>) at pthread_create.c:477
#9 0x00007fe60b94e293 in clone () at ../sysdeps/unix/sysv/linux/x86_64/clone.S:95

Thread 2 (Thread 0x7fe606602700 (LWP 80788)):
#0 0x00007fe60b941aff in __GI___poll (fds=0x7fe606601ba8, nfds=1, timeout=-1) at ../sysdeps/unix/sysv/linux/poll.c:29
#1 0x00007fe60a300c1a in () at /lib/x86_64-linux-gnu/libxcb.so.1
#2 0x00007fe60a30290a in xcb_wait_for_event () at /lib/x86_64-linux-gnu/libxcb.so.1
#3 0x00007fe606e01298 in () at /lib/x86_64-linux-gnu/libQt5XcbQpa.so.5
#4 0x00007fe60bcbf9d2 in () at /lib/x86_64-linux-gnu/libQt5Core.so.5
#5 0x00007fe60accd609 in start_thread (arg=<optimized out>) at pthread_create.c:477
#6 0x00007fe60b94e293 in clone () at ../sysdeps/unix/sysv/linux/x86_64/clone.S:95

Thread 1 (Thread 0x7fe607737f40 (LWP 80787)):
[KCrash Handler]
#6 0x0000000000000000 in ()
#7 0x00007fe5f641554c in () at /usr/lib/x86_64-linux-gnu/dri/r300_dri.so
#8 0x00007fe5f5edfbf4 in () at /usr/lib/x86_64-linux-gnu/dri/r300_dri.so
#9 0x00007fe5f5ee0e84 in () at /usr/lib/x86_64-linux-gnu/dri/r300_dri.so
#10 0x00007fe5f5ebe502 in () at /usr/lib/x86_64-linux-gnu/dri/r300_dri.so
#11 0x00007fe5f6413bf7 in () at /usr/lib/x86_64-linux-gnu/dri/r300_dri.so
#12 0x00007fe5f77bff53 in () at /lib/x86_64-linux-gnu/libGLX_mesa.so.0
#13 0x00007fe5f77b0119 in () at /lib/x86_64-linux-gnu/libGLX_mesa.so.0
#14 0x00007fe5f7843b0d in () at /usr/lib/x86_64-linux-gnu/qt5/plugins/xcbglintegrations/libqxcb-glx-integration.so
#15 0x00007fe5f7843b1d in () at /usr/lib/x86_64-linux-gnu/qt5/plugins/xcbglintegrations/libqxcb-glx-integration.so
#16 0x00007fe60c83bd2f in QOpenGLContext::destroy() () at /lib/x86_64-linux-gnu/libQt5Gui.so.5
#17 0x00007fe60c83bfdb in QOpenGLContext::~QOpenGLContext() () at /lib/x86_64-linux-gnu/libQt5Gui.so.5
#18 0x00007fe5f7845f80 in () at /usr/lib/x86_64-linux-gnu/qt5/plugins/xcbglintegrations/libqxcb-glx-integration.so
#19 0x00007fe5f784677d in () at /usr/lib/x86_64-linux-gnu/qt5/plugins/xcbglintegrations/libqxcb-glx-integration.so
#20 0x00007fe60d92f215 in QSGRenderLoop::instance() () at /lib/x86_64-linux-gnu/libQt5Quick.so.5
#21 0x00007fe60d9a6fe9 in QQuickWindowPrivate::init(QQuickWindow*, QQuickRenderControl*) () at /lib/x86_64-linux-gnu/libQt5Quick.so.5
#22 0x00007fe60da698e6 in QQuickWindowQmlImpl::QQuickWindowQmlImpl(QWindow*) () at /lib/x86_64-linux-gnu/libQt5Quick.so.5
#23 0x00007fe5f7b21117 in QQuickApplicationWindow::QQuickApplicationWindow(QWindow*) () at /lib/x86_64-linux-gnu/libQt5QuickTemplates2.so.5
#24 0x00007fe5f7923a4f in () at /usr/lib/x86_64-linux-gnu/qt5/qml/QtQuick/Templates.2/libqtquicktemplates2plugin.so
#25 0x00007fe60c4b666a in QQmlType::create(QObject**, void**, unsigned long) const () at /lib/x86_64-linux-gnu/libQt5Qml.so.5
#26 0x00007fe60c51ff00 in QQmlObjectCreator::createInstance(int, QObject*, bool) () at /lib/x86_64-linux-gnu/libQt5Qml.so.5
#27 0x00007fe60c52189c in QQmlObjectCreator::create(int, QObject*, QQmlInstantiationInterrupt*) () at /lib/x86_64-linux-gnu/libQt5Qml.so.5
#28 0x00007fe60c5202fa in QQmlObjectCreator::createInstance(int, QObject*, bool) () at /lib/x86_64-linux-gnu/libQt5Qml.so.5
#29 0x00007fe60c52189c in QQmlObjectCreator::create(int, QObject*, QQmlInstantiationInterrupt*) () at /lib/x86_64-linux-gnu/libQt5Qml.so.5
#30 0x00007fe60c5202fa in QQmlObjectCreator::createInstance(int, QObject*, bool) () at /lib/x86_64-linux-gnu/libQt5Qml.so.5
#31 0x00007fe60c52189c in QQmlObjectCreator::create(int, QObject*, QQmlInstantiationInterrupt*) () at /lib/x86_64-linux-gnu/libQt5Qml.so.5
#32 0x00007fe60c5202fa in QQmlObjectCreator::createInstance(int, QObject*, bool) () at /lib/x86_64-linux-gnu/libQt5Qml.so.5
#33 0x00007fe60c52189c in QQmlObjectCreator::create(int, QObject*, QQmlInstantiationInterrupt*) () at /lib/x86_64-linux-gnu/libQt5Qml.so.5
#34 0x00007fe60c5202fa in QQmlObjectCreator::createInstance(int, QObject*, bool) () at /lib/x86_64-linux-gnu/libQt5Qml.so.5
#35 0x00007fe60c52189c in QQmlObjectCreator::create(int, QObject*, QQmlInstantiationInterrupt*) () at /lib/x86_64-linux-gnu/libQt5Qml.so.5
#36 0x00007fe60c49b06f in QQmlComponentPrivate::beginCreate(QQmlContextData*) () at /lib/x86_64-linux-gnu/libQt5Qml.so.5
#37 0x00007fe60c4997b6 in QQmlComponent::create(QQmlContext*) () at /lib/x86_64-linux-gnu/libQt5Qml.so.5
#38 0x00007fe60c5102d7 in QQmlApplicationEnginePrivate::finishLoad(QQmlComponent*) () at /lib/x86_64-linux-gnu/libQt5Qml.so.5
#39 0x00007fe60c5107a6 in QQmlApplicationEnginePrivate::startLoad(QUrl const&, QByteArray const&, bool) () at /lib/x86_64-linux-gnu/libQt5Qml.so.5
#40 0x00007fe60c5107e1 in QQmlApplicationEngine::load(QUrl const&) () at /lib/x86_64-linux-gnu/libQt5Qml.so.5
#41 0x0000563fc25ef143 in ()
#42 0x0000563fc25e1320 in ()
#43 0x00007fe60b8530b3 in __libc_start_main (main=0x563fc25e0d00, argc=1, argv=0x7ffda3198db8, init=<optimized out>, fini=<optimized out>, rtld_fini=<optimized out>, stack_end=0x7ffda3198da8) at ../csu/libc-start.c:308
#44 0x0000563fc25e1b1e in _start ()
[Inferior 1 (process 80787) detached]