Bug 374890

can you try to gdb into the frozen process and get a backtrace?

I see what's happening now: the screen-locker is active on multiple monitors and only lets me enter the password on one of them. All the other monitors show the locker, but don't react to input.

Closing as Worksforme due to inactivity for more than 15 days as per:

https://community.kde.org/Guidelines_and_HOWTOs/Bug_triaging#Policies

Fanis

This bug was not NEEDSINFO

Certainly still "NotWorkingForMe". Happy to provide more info, but that's all I got for now.

Hi! I am seeing a similar issue for some time. Currently I am running kde plasma 5.16.3 on Gentoo, but the issue has persisted in one form or another for some time. Unfortunately, I haven't found the time to dig deeper in the past.

With the standard intel open source driver, I saw a bunch of hangs which could be prevented by setting LIBGL_DRI3_DISABLE=1 and I tried switching to the new intel iris driver, but to no avail.

I now collected backtraces in two conditions:
(1) kscreenlocker_greeter hangs while nothing happens. This can be noted by the clock showing a past time.
(2) After entering my password and pressing enter, the password field got greyed out and kscreenlocker_greeter hangs.

In both cases, the backtraces are identical (except for addresses, which obviously change):

Using host libthread_db library "/lib64/libthread_db.so.1".
futex_wait_cancelable (private=0, expected=0, futex_word=0x5609299964f0) at ../sysdeps/unix/sysv/linux/futex-internal.h:88
(gdb) #0  futex_wait_cancelable (private=0, expected=0, futex_word=0x5609299964f0) at ../sysdeps/unix/sysv/linux/futex-internal.h:88
#1  __pthread_cond_wait_common (abstime=0x0, mutex=0x5609299964a0, cond=0x5609299964c8) at pthread_cond_wait.c:502
#2  __pthread_cond_wait (cond=0x5609299964c8, mutex=0x5609299964a0) at pthread_cond_wait.c:655
#3  0x00007fb092f30e1b in QWaitConditionPrivate::wait (deadline=..., this=0x5609299964a0) at thread/qwaitcondition_unix.cpp:146
#4  QWaitCondition::wait (this=<optimized out>, mutex=0x560929a1bda0, deadline=...) at thread/qwaitcondition_unix.cpp:225
#5  0x00007fb092f30ea9 in QWaitCondition::wait (this=0x560929a1bda8, mutex=0x560929a1bda0, time=<optimized out>) at ../../include/QtCore/../../src/corelib/kernel/qdeadlinetimer.h:68
#6  0x00007fb0940e615e in QSGThreadedRenderLoop::polishAndSync(QSGThreadedRenderLoop::Window*, bool) () from /usr/lib64/libQt5Quick.so.5
#7  0x00007fb0940e6d0c in QSGThreadedRenderLoop::handleUpdateRequest(QQuickWindow*) () from /usr/lib64/libQt5Quick.so.5
#8  0x00007fb0941489ac in QQuickWindow::event(QEvent*) () from /usr/lib64/libQt5Quick.so.5
#9  0x00007fb0930c12e5 in doNotify (receiver=<optimized out>, event=<optimized out>) at ../../include/QtCore/../../src/corelib/kernel/qobject.h:142
#10 0x00007fb0930c136f in QCoreApplication::notifyInternal2 (receiver=0x560928ed2d40, event=0x7ffdd1f4c9e0) at kernel/qcoreapplication.cpp:1084
#11 0x00007fb09347b259 in QPlatformWindow::deliverUpdateRequest (this=<optimized out>) at kernel/qplatformwindow.cpp:793
#12 0x00007fb0934791ae in QPlatformWindow::windowEvent (this=0x560929cbaad0, event=<optimized out>) at kernel/qplatformwindow.cpp:478
#13 0x00007fb093485457 in QGuiApplication::notify (this=0x7ffdd1f4ce50, object=0x560928ed2d40, event=0x7ffdd1f4cae0) at kernel/qguiapplication.cpp:1792
#14 0x00007fb0930c136f in QCoreApplication::notifyInternal2 (receiver=0x560928ed2d40, event=0x7ffdd1f4cae0) at kernel/qcoreapplication.cpp:1084
#15 0x00007fb093113cbb in QTimerInfoList::activateTimers (this=0x560928cfdfd0) at kernel/qtimerinfo_unix.cpp:643
#16 0x00007fb09311457c in timerSourceDispatch (source=<optimized out>) at kernel/qeventdispatcher_glib.cpp:182
#17 idleTimerSourceDispatch (source=<optimized out>) at kernel/qeventdispatcher_glib.cpp:229
#18 0x00007fb0914ca91d in g_main_context_dispatch () from /usr/lib64/libglib-2.0.so.0
#19 0x00007fb0914cabb8 in g_main_context_iterate.isra () from /usr/lib64/libglib-2.0.so.0
#20 0x00007fb0914cac4c in g_main_context_iteration () from /usr/lib64/libglib-2.0.so.0
#21 0x00007fb0931149d0 in QEventDispatcherGlib::processEvents (this=0x560928ca74a0, flags=...) at kernel/qeventdispatcher_glib.cpp:422
#22 0x00007fb0930c02db in QEventLoop::exec (this=this@entry=0x7ffdd1f4cd40, flags=..., flags@entry=...) at ../../include/QtCore/../../src/corelib/global/qflags.h:140
#23 0x00007fb0930c7dc2 in QCoreApplication::exec () at ../../include/QtCore/../../src/corelib/global/qflags.h:120
#24 0x0000560927646c86 in main ()

In a probably related issue, I have seen frequent hangs in plasmashell and kwin_x11, which both need to be restarted several times a day to stay responsive.
I will open or contribute to different reports for these, nonetheless, I have the impression that there is a general graphics related issue here.
Also the screenlocker_greeter issue happens more than 50 % of the time.

Cheers,

Jan

> I now collected backtraces in two conditions:

I forgot to explicitly mention that these backtraces were all collected when using the iris driver. I will add backtraces for the standard intel i965 driver, but at least the observed behaviour is the same anyhow.

Just to make sure that the driver does not interfere I checked: the backtraces after not setting MESA_LOADER_DRIVER_OVERRIDE=iris look the same as with the iris driver.

Could you include all threads.

"thread apply all bt"

This just shows that we're blocked and waiting on the render thread to complete.

Can you reproduce with /usr/lib64/libexec/kscreenlocker_greet --testing ?

Hi! This backtrace is when directly calling with --testing . The hang occurred after entering the password.

[Thread debugging using libthread_db enabled]
Using host libthread_db library "/lib64/libthread_db.so.1".
futex_wait_cancelable (private=0, expected=0, futex_word=0x55d56d27a6a0) at ../sysdeps/unix/sysv/linux/futex-internal.h:88
88	  int err = lll_futex_timed_wait (futex_word, expected, NULL, private);
(gdb) 
Thread 15 (Thread 0x7f58577fe700 (LWP 12411)):
#0  futex_wait_cancelable (private=0, expected=0, futex_word=0x55d56cc66e00) at ../sysdeps/unix/sysv/linux/futex-internal.h:88
#1  __pthread_cond_wait_common (abstime=0x0, mutex=0x55d56cc66db0, cond=0x55d56cc66dd8) at pthread_cond_wait.c:502
#2  __pthread_cond_wait (cond=0x55d56cc66dd8, mutex=0x55d56cc66db0) at pthread_cond_wait.c:655
#3  0x00007f5899278e1b in QWaitConditionPrivate::wait (deadline=..., this=0x55d56cc66db0) at thread/qwaitcondition_unix.cpp:146
#4  QWaitCondition::wait (this=<optimized out>, mutex=0x55d56c9e35a8, deadline=...) at thread/qwaitcondition_unix.cpp:225
#5  0x00007f5899278ea9 in QWaitCondition::wait (this=0x55d56c9e35b0, mutex=0x55d56c9e35a8, time=<optimized out>) at ../../include/QtCore/../../src/corelib/kernel/qdeadlinetimer.h:68
#6  0x00007f587c4a220b in FileInfoThread::run() () from /usr/lib64/qt5/qml/Qt/labs/folderlistmodel/libqmlfolderlistmodelplugin.so
#7  0x00007f58992737d1 in QThreadPrivate::start (arg=0x55d56c9e3598) at thread/qthread_unix.cpp:361
#8  0x00007f5898684458 in start_thread (arg=<optimized out>) at pthread_create.c:486
#9  0x00007f5898e746ef in clone () at ../sysdeps/unix/sysv/linux/x86_64/clone.S:95

Thread 14 (Thread 0x7f5857fff700 (LWP 12410)):
#0  syscall () at ../sysdeps/unix/sysv/linux/x86_64/syscall.S:38
#1  0x00007f5899275988 in QtLinuxFutex::_q_futex (val3=0, addr2=0x0, val2=0, val=<optimized out>, op=0, addr=<optimized out>) at thread/qfutex_p.h:105
#2  QtLinuxFutex::futexWait<QBasicAtomicInteger<unsigned int> > (expectedValue=<optimized out>, futex=...) at thread/qfutex_p.h:107
#3  futexSemaphoreTryAcquire_loop<false> (timeout=<optimized out>, nn=8589934593, curValue=<optimized out>, u=...) at thread/qsemaphore.cpp:219
#4  futexSemaphoreTryAcquire<false> (u=..., n=<optimized out>, timeout=<optimized out>) at thread/qsemaphore.cpp:262
#5  0x00007f589444fb48 in QtVirtualKeyboard::HunspellWorker::run() () from /usr/lib64/libQt5HunspellInputMethod.so.5
#6  0x00007f58992737d1 in QThreadPrivate::start (arg=0x55d56ce9dac0) at thread/qthread_unix.cpp:361
#7  0x00007f5898684458 in start_thread (arg=<optimized out>) at pthread_create.c:486
#8  0x00007f5898e746ef in clone () at ../sysdeps/unix/sysv/linux/x86_64/clone.S:95

Thread 13 (Thread 0x7f5868c86700 (LWP 12409)):
#0  futex_wait_cancelable (private=0, expected=0, futex_word=0x55d56d428b80) at ../sysdeps/unix/sysv/linux/futex-internal.h:88
#1  __pthread_cond_wait_common (abstime=0x0, mutex=0x55d56d428b30, cond=0x55d56d428b58) at pthread_cond_wait.c:502
#2  __pthread_cond_wait (cond=0x55d56d428b58, mutex=0x55d56d428b30) at pthread_cond_wait.c:655
#3  0x00007f5899278e1b in QWaitConditionPrivate::wait (deadline=..., this=0x55d56d428b30) at thread/qwaitcondition_unix.cpp:146
#4  QWaitCondition::wait (this=<optimized out>, mutex=0x55d56d4289a8, deadline=...) at thread/qwaitcondition_unix.cpp:225
#5  0x00007f5899278ea9 in QWaitCondition::wait (this=0x55d56d4289b0, mutex=0x55d56d4289a8, time=<optimized out>) at ../../include/QtCore/../../src/corelib/kernel/qdeadlinetimer.h:68
#6  0x00007f587c4a220b in FileInfoThread::run() () from /usr/lib64/qt5/qml/Qt/labs/folderlistmodel/libqmlfolderlistmodelplugin.so
#7  0x00007f58992737d1 in QThreadPrivate::start (arg=0x55d56d428998) at thread/qthread_unix.cpp:361
#8  0x00007f5898684458 in start_thread (arg=<optimized out>) at pthread_create.c:486
#9  0x00007f5898e746ef in clone () at ../sysdeps/unix/sysv/linux/x86_64/clone.S:95

Thread 12 (Thread 0x7f5869487700 (LWP 12408)):
#0  syscall () at ../sysdeps/unix/sysv/linux/x86_64/syscall.S:38
#1  0x00007f5899275988 in QtLinuxFutex::_q_futex (val3=0, addr2=0x0, val2=0, val=<optimized out>, op=0, addr=<optimized out>) at thread/qfutex_p.h:105
#2  QtLinuxFutex::futexWait<QBasicAtomicInteger<unsigned int> > (expectedValue=<optimized out>, futex=...) at thread/qfutex_p.h:107
#3  futexSemaphoreTryAcquire_loop<false> (timeout=<optimized out>, nn=8589934593, curValue=<optimized out>, u=...) at thread/qsemaphore.cpp:219
#4  futexSemaphoreTryAcquire<false> (u=..., n=<optimized out>, timeout=<optimized out>) at thread/qsemaphore.cpp:262
#5  0x00007f589444fb48 in QtVirtualKeyboard::HunspellWorker::run() () from /usr/lib64/libQt5HunspellInputMethod.so.5
#6  0x00007f58992737d1 in QThreadPrivate::start (arg=0x55d56d40cf60) at thread/qthread_unix.cpp:361
#7  0x00007f5898684458 in start_thread (arg=<optimized out>) at pthread_create.c:486
#8  0x00007f5898e746ef in clone () at ../sysdeps/unix/sysv/linux/x86_64/clone.S:95

Thread 11 (Thread 0x7f5874b87700 (LWP 12407)):
#0  futex_wait_cancelable (private=0, expected=0, futex_word=0x55d56c885e30) at ../sysdeps/unix/sysv/linux/futex-internal.h:88
#1  __pthread_cond_wait_common (abstime=0x0, mutex=0x55d56c885de0, cond=0x55d56c885e08) at pthread_cond_wait.c:502
#2  __pthread_cond_wait (cond=0x55d56c885e08, mutex=0x55d56c885de0) at pthread_cond_wait.c:655
#3  0x00007f5899278e1b in QWaitConditionPrivate::wait (deadline=..., this=0x55d56c885de0) at thread/qwaitcondition_unix.cpp:146
#4  QWaitCondition::wait (this=<optimized out>, mutex=0x55d56d56bf18, deadline=...) at thread/qwaitcondition_unix.cpp:225
#5  0x00007f5899278ea9 in QWaitCondition::wait (this=0x55d56d56bf20, mutex=0x55d56d56bf18, time=<optimized out>) at ../../include/QtCore/../../src/corelib/kernel/qdeadlinetimer.h:68
#6  0x00007f587c4a220b in FileInfoThread::run() () from /usr/lib64/qt5/qml/Qt/labs/folderlistmodel/libqmlfolderlistmodelplugin.so
#7  0x00007f58992737d1 in QThreadPrivate::start (arg=0x55d56d56bf08) at thread/qthread_unix.cpp:361
#8  0x00007f5898684458 in start_thread (arg=<optimized out>) at pthread_create.c:486
#9  0x00007f5898e746ef in clone () at ../sysdeps/unix/sysv/linux/x86_64/clone.S:95

Thread 10 (Thread 0x7f5875388700 (LWP 12405)):
#0  syscall () at ../sysdeps/unix/sysv/linux/x86_64/syscall.S:38
#1  0x00007f5899275988 in QtLinuxFutex::_q_futex (val3=0, addr2=0x0, val2=0, val=<optimized out>, op=0, addr=<optimized out>) at thread/qfutex_p.h:105
#2  QtLinuxFutex::futexWait<QBasicAtomicInteger<unsigned int> > (expectedValue=<optimized out>, futex=...) at thread/qfutex_p.h:107
#3  futexSemaphoreTryAcquire_loop<false> (timeout=<optimized out>, nn=8589934593, curValue=<optimized out>, u=...) at thread/qsemaphore.cpp:219
#4  futexSemaphoreTryAcquire<false> (u=..., n=<optimized out>, timeout=<optimized out>) at thread/qsemaphore.cpp:262
#5  0x00007f589444fb48 in QtVirtualKeyboard::HunspellWorker::run() () from /usr/lib64/libQt5HunspellInputMethod.so.5
#6  0x00007f58992737d1 in QThreadPrivate::start (arg=0x55d56d0bfd80) at thread/qthread_unix.cpp:361
#7  0x00007f5898684458 in start_thread (arg=<optimized out>) at pthread_create.c:486
#8  0x00007f5898e746ef in clone () at ../sysdeps/unix/sysv/linux/x86_64/clone.S:95

Thread 9 (Thread 0x7f587d0ec700 (LWP 12403)):
#0  futex_wait_cancelable (private=0, expected=0, futex_word=0x55d56d2ecf44) at ../sysdeps/unix/sysv/linux/futex-internal.h:88
#1  __pthread_cond_wait_common (abstime=0x0, mutex=0x55d56d2ecef0, cond=0x55d56d2ecf18) at pthread_cond_wait.c:502
#2  __pthread_cond_wait (cond=0x55d56d2ecf18, mutex=0x55d56d2ecef0) at pthread_cond_wait.c:655
#3  0x00007f5899278e1b in QWaitConditionPrivate::wait (deadline=..., this=0x55d56d2ecef0) at thread/qwaitcondition_unix.cpp:146
#4  QWaitCondition::wait (this=<optimized out>, mutex=0x55d56d512eb0, deadline=...) at thread/qwaitcondition_unix.cpp:225
#5  0x00007f5899278ea9 in QWaitCondition::wait (this=0x55d56d512eb8, mutex=0x55d56d512eb0, time=<optimized out>) at ../../include/QtCore/../../src/corelib/kernel/qdeadlinetimer.h:68
#6  0x00007f589a42fb29 in QSGRenderThread::processEventsAndWaitForMore() () from /usr/lib64/libQt5Quick.so.5
#7  0x00007f589a42fdcd in QSGRenderThread::run() () from /usr/lib64/libQt5Quick.so.5
#8  0x00007f58992737d1 in QThreadPrivate::start (arg=0x55d56d512e30) at thread/qthread_unix.cpp:361
#9  0x00007f5898684458 in start_thread (arg=<optimized out>) at pthread_create.c:486
#10 0x00007f5898e746ef in clone () at ../sysdeps/unix/sysv/linux/x86_64/clone.S:95

Thread 8 (Thread 0x7f587d8ed700 (LWP 12402)):
#0  0x00007f5898e68633 in __GI___poll (fds=0x7f587d8ec5c8, nfds=1, timeout=-1) at ../sysdeps/unix/sysv/linux/poll.c:29
#1  0x00007f58986cecf7 in _xcb_conn_wait () from /usr/lib64/libxcb.so.1
#2  0x00007f58986d0a1a in xcb_wait_for_special_event () from /usr/lib64/libxcb.so.1
#3  0x00007f5897facf4e in dri3_wait_for_event_locked () from /usr/lib64/libGL.so.1
#4  0x00007f5897fad0b0 in dri3_find_back () from /usr/lib64/libGL.so.1
#5  0x00007f5897fae29e in dri3_get_buffer.isra () from /usr/lib64/libGL.so.1
#6  0x00007f5897faf1cb in loader_dri3_get_buffers () from /usr/lib64/libGL.so.1
#7  0x00007f588ec74b98 in intel_update_renderbuffers () from /usr/lib64/dri/i965_dri.so
#8  0x00007f588ec75325 in intel_prepare_render () from /usr/lib64/dri/i965_dri.so
#9  0x00007f588ec70f97 in brw_clear () from /usr/lib64/dri/i965_dri.so
#10 0x00007f589a3ecbdb in QSGBatchRenderer::Renderer::renderBatches() () from /usr/lib64/libQt5Quick.so.5
#11 0x00007f589a3f2aaf in QSGBatchRenderer::Renderer::render() () from /usr/lib64/libQt5Quick.so.5
#12 0x00007f589a3e050e in QSGRenderer::renderScene(QSGBindable const&) () from /usr/lib64/libQt5Quick.so.5
#13 0x00007f589a3e09db in QSGRenderer::renderScene(unsigned int) () from /usr/lib64/libQt5Quick.so.5
#14 0x00007f589a4201e0 in QSGDefaultRenderContext::renderNextFrame(QSGRenderer*, unsigned int) () from /usr/lib64/libQt5Quick.so.5
#15 0x00007f589a483f9a in QQuickWindowPrivate::renderSceneGraph(QSize const&) () from /usr/lib64/libQt5Quick.so.5
#16 0x00007f589a42c024 in QSGRenderThread::syncAndRender() () from /usr/lib64/libQt5Quick.so.5
#17 0x00007f589a42fd38 in QSGRenderThread::run() () from /usr/lib64/libQt5Quick.so.5
#18 0x00007f58992737d1 in QThreadPrivate::start (arg=0x55d56c53bc90) at thread/qthread_unix.cpp:361
#19 0x00007f5898684458 in start_thread (arg=<optimized out>) at pthread_create.c:486
#20 0x00007f5898e746ef in clone () at ../sysdeps/unix/sysv/linux/x86_64/clone.S:95

Thread 7 (Thread 0x7f587e447700 (LWP 12401)):
#0  futex_wait_cancelable (private=0, expected=0, futex_word=0x55d56d3625a4) at ../sysdeps/unix/sysv/linux/futex-internal.h:88
#1  __pthread_cond_wait_common (abstime=0x0, mutex=0x55d56d362550, cond=0x55d56d362578) at pthread_cond_wait.c:502
#2  __pthread_cond_wait (cond=0x55d56d362578, mutex=0x55d56d362550) at pthread_cond_wait.c:655
#3  0x00007f5899278e1b in QWaitConditionPrivate::wait (deadline=..., this=0x55d56d362550) at thread/qwaitcondition_unix.cpp:146
#4  QWaitCondition::wait (this=<optimized out>, mutex=0x55d56d3c3650, deadline=...) at thread/qwaitcondition_unix.cpp:225
#5  0x00007f5899278ea9 in QWaitCondition::wait (this=0x55d56d3c3658, mutex=0x55d56d3c3650, time=<optimized out>) at ../../include/QtCore/../../src/corelib/kernel/qdeadlinetimer.h:68
#6  0x00007f589a42fb29 in QSGRenderThread::processEventsAndWaitForMore() () from /usr/lib64/libQt5Quick.so.5
#7  0x00007f589a42fdcd in QSGRenderThread::run() () from /usr/lib64/libQt5Quick.so.5
#8  0x00007f58992737d1 in QThreadPrivate::start (arg=0x55d56d3c35d0) at thread/qthread_unix.cpp:361
#9  0x00007f5898684458 in start_thread (arg=<optimized out>) at pthread_create.c:486
#10 0x00007f5898e746ef in clone () at ../sysdeps/unix/sysv/linux/x86_64/clone.S:95

Thread 6 (Thread 0x7f587efc0700 (LWP 12400)):
#0  0x00007f5898e68633 in __GI___poll (fds=0x7f5878c14fe0, nfds=1, timeout=-1) at ../sysdeps/unix/sysv/linux/poll.c:29
#1  0x00007f5897812b26 in g_main_context_iterate.isra () from /usr/lib64/libglib-2.0.so.0
#2  0x00007f5897812c4c in g_main_context_iteration () from /usr/lib64/libglib-2.0.so.0
#3  0x00007f589945c9d0 in QEventDispatcherGlib::processEvents (this=0x7f5878000b20, flags=...) at kernel/qeventdispatcher_glib.cpp:422
#4  0x00007f58994082db in QEventLoop::exec (this=this@entry=0x7f587efbfde0, flags=..., flags@entry=...) at ../../include/QtCore/../../src/corelib/global/qflags.h:140
#5  0x00007f5899272741 in QThread::exec (this=<optimized out>) at ../../include/QtCore/../../src/corelib/global/qflags.h:120
#6  0x00007f589a3a80d6 in QQuickPixmapReader::run() () from /usr/lib64/libQt5Quick.so.5
#7  0x00007f58992737d1 in QThreadPrivate::start (arg=0x55d56d36cee0) at thread/qthread_unix.cpp:361
#8  0x00007f5898684458 in start_thread (arg=<optimized out>) at pthread_create.c:486
#9  0x00007f5898e746ef in clone () at ../sysdeps/unix/sysv/linux/x86_64/clone.S:95

Thread 5 (Thread 0x7f588e2a5700 (LWP 12398)):
#0  0x00007f5898e68633 in __GI___poll (fds=0x7f5884004a00, nfds=1, timeout=-1) at ../sysdeps/unix/sysv/linux/poll.c:29
#1  0x00007f5897812b26 in g_main_context_iterate.isra () from /usr/lib64/libglib-2.0.so.0
#2  0x00007f5897812c4c in g_main_context_iteration () from /usr/lib64/libglib-2.0.so.0
#3  0x00007f589945c9d0 in QEventDispatcherGlib::processEvents (this=0x7f5884000b20, flags=...) at kernel/qeventdispatcher_glib.cpp:422
#4  0x00007f58994082db in QEventLoop::exec (this=this@entry=0x7f588e2a4e00, flags=..., flags@entry=...) at ../../include/QtCore/../../src/corelib/global/qflags.h:140
#5  0x00007f5899272741 in QThread::exec (this=<optimized out>) at ../../include/QtCore/../../src/corelib/global/qflags.h:120
#6  0x00007f589a0d2f05 in QQmlThreadPrivate::run() () from /usr/lib64/libQt5Qml.so.5
#7  0x00007f58992737d1 in QThreadPrivate::start (arg=0x55d56c5c4b80) at thread/qthread_unix.cpp:361
#8  0x00007f5898684458 in start_thread (arg=<optimized out>) at pthread_create.c:486
#9  0x00007f5898e746ef in clone () at ../sysdeps/unix/sysv/linux/x86_64/clone.S:95

Thread 4 (Thread 0x7f588ced4700 (LWP 12397)):
#0  0x00007f5898e68633 in __GI___poll (fds=0x7f58800096f0, nfds=4, timeout=-1) at ../sysdeps/unix/sysv/linux/poll.c:29
#1  0x00007f5897812b26 in g_main_context_iterate.isra () from /usr/lib64/libglib-2.0.so.0
#2  0x00007f5897812c4c in g_main_context_iteration () from /usr/lib64/libglib-2.0.so.0
#3  0x00007f589945c9d0 in QEventDispatcherGlib::processEvents (this=0x7f5880000b20, flags=...) at kernel/qeventdispatcher_glib.cpp:422
#4  0x00007f58994082db in QEventLoop::exec (this=this@entry=0x7f588ced3de0, flags=..., flags@entry=...) at ../../include/QtCore/../../src/corelib/global/qflags.h:140
#5  0x00007f5899272741 in QThread::exec (this=this@entry=0x7f589a7bfd80 <(anonymous namespace)::Q_QGS__q_manager::innerFunction()::holder>) at ../../include/QtCore/../../src/corelib/global/qflags.h:120
#6  0x00007f589a73d4f7 in QDBusConnectionManager::run (this=0x7f589a7bfd80 <(anonymous namespace)::Q_QGS__q_manager::innerFunction()::holder>) at qdbusconnection.cpp:178
#7  0x00007f58992737d1 in QThreadPrivate::start (arg=0x7f589a7bfd80 <(anonymous namespace)::Q_QGS__q_manager::innerFunction()::holder>) at thread/qthread_unix.cpp:361
#8  0x00007f5898684458 in start_thread (arg=<optimized out>) at pthread_create.c:486
#9  0x00007f5898e746ef in clone () at ../sysdeps/unix/sysv/linux/x86_64/clone.S:95

Thread 3 (Thread 0x7f588eaa6700 (LWP 12396)):
#0  futex_wait_cancelable (private=0, expected=0, futex_word=0x55d56c5cd348) at ../sysdeps/unix/sysv/linux/futex-internal.h:88
#1  __pthread_cond_wait_common (abstime=0x0, mutex=0x55d56c5cd2f8, cond=0x55d56c5cd320) at pthread_cond_wait.c:502
#2  __pthread_cond_wait (cond=0x55d56c5cd320, mutex=0x55d56c5cd2f8) at pthread_cond_wait.c:655
#3  0x00007f588ecb2b6b in util_queue_thread_func () from /usr/lib64/dri/i965_dri.so
#4  0x00007f588ecb2787 in impl_thrd_routine () from /usr/lib64/dri/i965_dri.so
#5  0x00007f5898684458 in start_thread (arg=<optimized out>) at pthread_create.c:486
#6  0x00007f5898e746ef in clone () at ../sysdeps/unix/sysv/linux/x86_64/clone.S:95

Thread 2 (Thread 0x7f5894c78700 (LWP 12394)):
#0  futex_wait_cancelable (private=0, expected=0, futex_word=0x55d56c530ec8) at ../sysdeps/unix/sysv/linux/futex-internal.h:88
#1  __pthread_cond_wait_common (abstime=0x0, mutex=0x55d56c530e78, cond=0x55d56c530ea0) at pthread_cond_wait.c:502
#2  __pthread_cond_wait (cond=0x55d56c530ea0, mutex=0x55d56c530e78) at pthread_cond_wait.c:655
#3  0x00007f58986cef02 in _xcb_conn_wait () from /usr/lib64/libxcb.so.1
#4  0x00007f58986d092a in xcb_wait_for_event () from /usr/lib64/libxcb.so.1
#5  0x00007f5894df0808 in QXcbEventQueue::run (this=0x55d56c53d610) at qxcbeventqueue.cpp:228
#6  0x00007f58992737d1 in QThreadPrivate::start (arg=0x55d56c53d610) at thread/qthread_unix.cpp:361
#7  0x00007f5898684458 in start_thread (arg=<optimized out>) at pthread_create.c:486
#8  0x00007f5898e746ef in clone () at ../sysdeps/unix/sysv/linux/x86_64/clone.S:95

Thread 1 (Thread 0x7f5895510640 (LWP 12393)):
#0  futex_wait_cancelable (private=0, expected=0, futex_word=0x55d56d27a6a0) at ../sysdeps/unix/sysv/linux/futex-internal.h:88
#1  __pthread_cond_wait_common (abstime=0x0, mutex=0x55d56d27a650, cond=0x55d56d27a678) at pthread_cond_wait.c:502
#2  __pthread_cond_wait (cond=0x55d56d27a678, mutex=0x55d56d27a650) at pthread_cond_wait.c:655
#3  0x00007f5899278e1b in QWaitConditionPrivate::wait (deadline=..., this=0x55d56d27a650) at thread/qwaitcondition_unix.cpp:146
#4  QWaitCondition::wait (this=<optimized out>, mutex=0x55d56c53bcd0, deadline=...) at thread/qwaitcondition_unix.cpp:225
#5  0x00007f5899278ea9 in QWaitCondition::wait (this=0x55d56c53bcd8, mutex=0x55d56c53bcd0, time=<optimized out>) at ../../include/QtCore/../../src/corelib/kernel/qdeadlinetimer.h:68
#6  0x00007f589a42e15e in QSGThreadedRenderLoop::polishAndSync(QSGThreadedRenderLoop::Window*, bool) () from /usr/lib64/libQt5Quick.so.5
#7  0x00007f589a42ed0c in QSGThreadedRenderLoop::handleUpdateRequest(QQuickWindow*) () from /usr/lib64/libQt5Quick.so.5
#8  0x00007f589a4909ac in QQuickWindow::event(QEvent*) () from /usr/lib64/libQt5Quick.so.5
#9  0x00007f58994092e5 in doNotify (receiver=<optimized out>, event=<optimized out>) at ../../include/QtCore/../../src/corelib/kernel/qobject.h:142
#10 0x00007f589940936f in QCoreApplication::notifyInternal2 (receiver=0x55d56c7eba20, event=0x7fff47930c90) at kernel/qcoreapplication.cpp:1084
#11 0x00007f58997c3259 in QPlatformWindow::deliverUpdateRequest (this=<optimized out>) at kernel/qplatformwindow.cpp:793
#12 0x00007f58997c11ae in QPlatformWindow::windowEvent (this=0x55d56d5f8fb0, event=<optimized out>) at kernel/qplatformwindow.cpp:478
#13 0x00007f58997cd457 in QGuiApplication::notify (this=0x7fff47931100, object=0x55d56c7eba20, event=0x7fff47930d90) at kernel/qguiapplication.cpp:1792
#14 0x00007f589940936f in QCoreApplication::notifyInternal2 (receiver=0x55d56c7eba20, event=0x7fff47930d90) at kernel/qcoreapplication.cpp:1084
#15 0x00007f589945bcbb in QTimerInfoList::activateTimers (this=0x55d56c57a410) at kernel/qtimerinfo_unix.cpp:643
#16 0x00007f589945c544 in timerSourceDispatch (source=<optimized out>) at kernel/qeventdispatcher_glib.cpp:182
#17 0x00007f589781291d in g_main_context_dispatch () from /usr/lib64/libglib-2.0.so.0
#18 0x00007f5897812bb8 in g_main_context_iterate.isra () from /usr/lib64/libglib-2.0.so.0
#19 0x00007f5897812c4c in g_main_context_iteration () from /usr/lib64/libglib-2.0.so.0
#20 0x00007f589945c9d0 in QEventDispatcherGlib::processEvents (this=0x55d56c5238d0, flags=...) at kernel/qeventdispatcher_glib.cpp:422
#21 0x00007f58994082db in QEventLoop::exec (this=this@entry=0x7fff47930ff0, flags=..., flags@entry=...) at ../../include/QtCore/../../src/corelib/global/qflags.h:140
#22 0x00007f589940fdc2 in QCoreApplication::exec () at ../../include/QtCore/../../src/corelib/global/qflags.h:120
#23 0x000055d56a943c86 in main ()

Is there any more information I could provide?
(I do think that there are general problems -- at least with the intel OpenGL -- stack, as kwin_x11, plasmashell, and krunner also sometimes freeze).
But I don't know how to approach this aspect in a suitable manner.

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
mark the bug 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!

New information was added with comment #10; changing status for inspection.

Some more testing … with probably unhelpful outcome.
On a machine with an old nvidia graphics card, I cannot observe any issue.

On the questionable machine with Intel graphics, I had a period last week where I haven't seen kscreenlocker_greet lock up for several days in a row. But now I am back to lock up.Of course, there were plasma, frameworks, and mesa updates in between.

I could also observe the krunner, plasmashell and kwin lock ups only on the Intel graphics card,

On an interesting side note, I have observed that not all screens are frozen at the same time, i.e., the laptop display stopped three minutes before the two external ones.

Hi,

I also have the same issue on both my laptop and workstation running Arch Linux. Currently I'm running plasma-desktop 5.19.4-1 from the standard archlinux package repository. Please let me know if I can provide any more info.

I had a similar problem on ubuntu 20.04

Symptom:
Every 1-20 times I locked the screen and entered my password, kscreenlocker_greet would freeze.  It was really sporatic.  I tried the kscreenlocker_greet from ubuntu 18.04 on my ubuntu 20.04 system, and it still froze.  I tried gnome running on X11 and kscreenlocker_greet still froze.  I tried gnome running on Wayland and it DID NOT freeze!  That's an important clue.  The problem is some interaction of the compositor and/or/xserver with kscreenlocker_Greet.

I deleted my home directory (after making a backup) and it did not have the same problem.  I did a binary search on the difference between the directories and after maybe 40 iterations, arrived at this:

Removing one line in my ~/.config/kwinrc made the problem go from on (freezes) to off (stable).  The line is:

[Compositing]
Enabled=false  #This line.

So apparently kscreenlocker_greet is no longer compatible with not using compositing?  I hope this is enough that a kde dev can reproduce the issue and fix this for other people.  I'm all set now.

Here's the kwinrc that makes kscreenlocker_greet freeze:
[$Version]
update_info=kwin.upd:replace-scalein-with-scale,kwin.upd:port-minimizeanimation-effect-to-js,kwin.upd:port-scale-effect-to-js,kwin.upd:port-dimscreen-effect-to-js,kwin.upd:auto-bordersize,kwin.upd:animation-speed

[Compositing]
Enabled=false
HiddenPreviews=5
OpenGLIsUnsafe=false
WindowsBlockCompositing=true
XRenderSmoothScale=false

[Desktops]
Id_1=a241fd47-9437-47b7-b764-124a8c91f1d9
Id_2=0d7a84de-7f6c-4149-b2f1-9227a968269f
Id_3=93b59d33-56cc-44fd-b9e4-7e0fbc79c261
Id_4=530b8cd9-6c31-4e41-97e6-2b896c79a1a9
Number=4
Rows=1

[Effect-Zoom]
InitialZoom=1

[MouseBindings]
CommandActiveTitlebar1=Raise
CommandActiveTitlebar2=Start window tab drag
CommandActiveTitlebar3=Operations menu
CommandAll1=Move
CommandAll2=Toggle raise and lower
CommandAll3=Resize
CommandAllKey=Alt
CommandAllWheel=Nothing
CommandInactiveTitlebar1=Activate and raise
CommandInactiveTitlebar2=Start window tab drag
CommandInactiveTitlebar3=Operations menu
CommandTitlebarWheel=Switch to Window Tab to the Left/Right
CommandWindow1=Activate, raise and pass click
CommandWindow2=Activate and pass click
CommandWindow3=Activate and pass click
CommandWindowWheel=Scroll

[Plugins]
cubeslideEnabled=false
desktopchangeosdEnabled=false
kwin4_effect_fadedesktopEnabled=false
slideEnabled=true
windowgeometryEnabled=false

[Script-desktopchangeosd]
PopupHideDelay=1000
TextOnly=false

[TabBox]
DesktopLayout=org.kde.breeze.desktop
DesktopListLayout=org.kde.breeze.desktop
LayoutName=org.kde.breeze.desktop

[Windows]
ActiveMouseScreen=false
AutoRaise=false
AutoRaiseInterval=750
AutogroupInForeground=true
AutogroupSimilarWindows=false
BorderSnapZone=10
CenterSnapZone=0
ClickRaise=true
DelayFocusInterval=300
FocusPolicy=ClickToFocus
FocusStealingPreventionLevel=1
GeometryTip=false
HideUtilityWindowsForInactive=true
InactiveTabsSkipTaskbar=false
MaximizeButtonLeftClickCommand=Maximize
MaximizeButtonMiddleClickCommand=Maximize (vertical only)
MaximizeButtonRightClickCommand=Maximize (horizontal only)
NextFocusPrefersMouse=false
Placement=Smart
RollOverDesktops=true
SeparateScreenFocus=false
ShadeHover=false
ShadeHoverInterval=250
SnapOnlyWhenOverlapping=false
TitlebarDoubleClickCommand=Maximize
WindowSnapZone=10

[org.kde.kdecoration2]
BorderSize=Tiny
BorderSizeAuto=false
ButtonsOnLeft=M
ButtonsOnRight=HIAX
CloseOnDoubleClickOnMenu=false
library=org.kde.kwin.aurorae
theme=kwin4_decoration_qml_plastik

Here's the closest one that makes it not freeze:
[$Version]
update_info=kwin.upd:replace-scalein-with-scale,kwin.upd:port-minimizeanimation-effect-to-js,kwin.upd:port-scale-effect-to-js,kwin.upd:port-dimscreen-effect-to-js,kwin.upd:auto-bordersize,kwin.upd:animation-speed

[Compositing]
HiddenPreviews=5
OpenGLIsUnsafe=false
WindowsBlockCompositing=true
XRenderSmoothScale=false

[Desktops]
Id_1=a241fd47-9437-47b7-b764-124a8c91f1d9
Id_2=0d7a84de-7f6c-4149-b2f1-9227a968269f
Id_3=93b59d33-56cc-44fd-b9e4-7e0fbc79c261
Id_4=530b8cd9-6c31-4e41-97e6-2b896c79a1a9
Number=4
Rows=1

[Effect-Zoom]
InitialZoom=1

[MouseBindings]
CommandActiveTitlebar1=Raise
CommandActiveTitlebar2=Start window tab drag
CommandActiveTitlebar3=Operations menu
CommandAll1=Move
CommandAll2=Toggle raise and lower
CommandAll3=Resize
CommandAllKey=Alt
CommandAllWheel=Nothing
CommandInactiveTitlebar1=Activate and raise
CommandInactiveTitlebar2=Start window tab drag
CommandInactiveTitlebar3=Operations menu
CommandTitlebarWheel=Switch to Window Tab to the Left/Right
CommandWindow1=Activate, raise and pass click
CommandWindow2=Activate and pass click
CommandWindow3=Activate and pass click
CommandWindowWheel=Scroll

[Plugins]
cubeslideEnabled=false
desktopchangeosdEnabled=false
kwin4_effect_fadedesktopEnabled=false
slideEnabled=true
windowgeometryEnabled=false

[Script-desktopchangeosd]
PopupHideDelay=1000
TextOnly=false

[TabBox]
DesktopLayout=org.kde.breeze.desktop
DesktopListLayout=org.kde.breeze.desktop
LayoutName=org.kde.breeze.desktop

[Windows]
ActiveMouseScreen=false
AutoRaise=false
AutoRaiseInterval=750
AutogroupInForeground=true
AutogroupSimilarWindows=false
BorderSnapZone=10
CenterSnapZone=0
ClickRaise=true
DelayFocusInterval=300
FocusPolicy=ClickToFocus
FocusStealingPreventionLevel=1
GeometryTip=false
HideUtilityWindowsForInactive=true
InactiveTabsSkipTaskbar=false
MaximizeButtonLeftClickCommand=Maximize
MaximizeButtonMiddleClickCommand=Maximize (vertical only)
MaximizeButtonRightClickCommand=Maximize (horizontal only)
NextFocusPrefersMouse=false
Placement=Smart
RollOverDesktops=true
SeparateScreenFocus=false
ShadeHover=false
ShadeHoverInterval=250
SnapOnlyWhenOverlapping=false
TitlebarDoubleClickCommand=Maximize
WindowSnapZone=10

[org.kde.kdecoration2]
BorderSize=Tiny
BorderSizeAuto=false
ButtonsOnLeft=M
ButtonsOnRight=HIAX
CloseOnDoubleClickOnMenu=false
library=org.kde.kwin.aurorae
theme=kwin4_decoration_qml_plastik

Created attachment 135426 [details]
backtrace kscreenlocker_greet --testing

I've been seeing a similar behavior also on archlinux: from time to time kscreenlocker_greet will "hang", the clock displayed is frozen at the time the hang occurred. The mouse can be moved, but I can't input a password.
The only way I found to be able to unlock is to switch to console, login and kill -9 the process (SIGTERM doesn't seem to do anything).

This is a backtrace of `kscreenlocker_greet --testing` taken on archlinux on a lenovo x1c5 running kernel 5.10.11-arch1-1.
(I'm not sure when I started observing this behavior exactly, it "feels" like it has been multiple weeks/months now)
There are 2 displays connected, when the hang occurs, the time displayed on each screen can be different (in this particular instance, the laptop display showed 10:20:41 whereas the external display showed 10:20:43.

Another thing that might be of interest: the taskbar freezes / become unresponsive multiple times a week.
I haven't got a backtrace for this, but the bahavior seems similar enough that I think it is worth mentioning.

The output of kscreenlock_greet doesn't seem to indicate anything related to this issue:

Locked at 1612450835
kf.coreaddons: KDirWatch: "/usr/share/wallpapers/Next" is a directory. Use addDir!
qt.svg: <input>:406:376: Could not add child element to parent element because the types are incorrect.
qt.svg: <input>:407:130: Could not add child element to parent element because the types are incorrect.
qt.svg: <input>:408:130: Could not add child element to parent element because the types are incorrect.
qt.svg: <input>:408:393: Could not add child element to parent element because the types are incorrect.
qt.svg: <input>:409:130: Could not add child element to parent element because the types are incorrect.
qt.svg: <input>:410:129: Could not add child element to parent element because the types are incorrect.
qt.svg: <input>:411:129: Could not add child element to parent element because the types are incorrect.
qt.svg: <input>:412:129: Could not add child element to parent element because the types are incorrect.
qt.svg: <input>:413:129: Could not add child element to parent element because the types are incorrect.
qt.svg: <input>:413:379: Could not add child element to parent element because the types are incorrect.
qt.svg: <input>:413:631: Could not add child element to parent element because the types are incorrect.
Connecting to deprecated signal QDBusConnectionInterface::serviceOwnerChanged(QString,QString,QString)
file:///usr/share/plasma/look-and-feel/org.kde.breeze.desktop/contents/components/VirtualKeyboard.qml:20:1: module "QtQuick.VirtualKeyboard" is not installed
file:///usr/share/plasma/look-and-feel/org.kde.breeze.desktop/contents/components/VirtualKeyboard.qml:20:1: module "QtQuick.VirtualKeyboard" is not installed
QXcbClipboard: SelectionRequest too old
QXcbClipboard: SelectionRequest too old


Relevant Xorg log excerpt:

[     5.000] (II) Loading /usr/lib/xorg/modules/drivers/intel_drv.so
[     5.003] (II) Module intel: vendor="X.Org Foundation"
[     5.003]    compiled for 1.20.10, module version = 2.99.917
[     5.003]    Module class: X.Org Video Driver
[     5.003]    ABI class: X.Org Video Driver, version 24.1
[     5.003] (II) intel: Driver for Intel(R) Integrated Graphics Chipsets:
        i810, i810-dc100, i810e, i815, i830M, 845G, 854, 852GM/855GM, 865G,
        915G, E7221 (i915), 915GM, 945G, 945GM, 945GME, Pineview GM,
        Pineview G, 965G, G35, 965Q, 946GZ, 965GM, 965GME/GLE, G33, Q35, Q33,
        GM45, 4 Series, G45/G43, Q45/Q43, G41, B43
[     5.003] (II) intel: Driver for Intel(R) HD Graphics
[     5.003] (II) intel: Driver for Intel(R) Iris(TM) Graphics
[     5.003] (II) intel: Driver for Intel(R) Iris(TM) Pro Graphics
[     5.004] (II) intel(0): Using Kernel Mode Setting driver: i915, version 1.6.0 20200917
[     5.004] (II) intel(0): SNA compiled from 2.99.917-916-g31486f40
[     5.021] (--) intel(0): Integrated Graphics Chipset: Intel(R) HD Graphics 620
[     5.021] (--) intel(0): CPU: x86-64, sse2, sse3, ssse3, sse4.1, sse4.2, avx, avx2; using a maximum of 2 threads
[     5.021] (II) intel(0): Creating default Display subsection in Screen section
        "Default Screen Section" for depth/fbbpp 24/32
[     5.021] (==) intel(0): Depth 24, (--) framebuffer bpp 32
[     5.021] (==) intel(0): RGB weight 888
[     5.021] (==) intel(0): Default visual is TrueColor
[     5.021] (**) intel(0): Option "TearFree" "true"
[     5.022] (II) intel(0): Output eDP1 has no monitor section
[     5.023] (**) intel(0): Found backlight control interface intel_backlight (type 'raw') for output eDP1
[     5.023] (II) intel(0): Enabled output eDP1
[     5.023] (II) intel(0): Output DP1 has no monitor section
[     5.023] (II) intel(0): Enabled output DP1
[     5.023] (II) intel(0): Output HDMI1 has no monitor section
[     5.023] (II) intel(0): Enabled output HDMI1
[     5.023] (II) intel(0): Output DP2 has no monitor section
[     5.023] (II) intel(0): Enabled output DP2
[     5.023] (--) intel(0): Using a maximum size of 256x256 for hardware cursors
[     5.024] (II) intel(0): Output VIRTUAL1 has no monitor section
[     5.024] (II) intel(0): Enabled output VIRTUAL1
[     5.024] (--) intel(0): Output eDP1 using initial mode 1920x1080 on pipe 0
[     5.024] (--) intel(0): Output HDMI1 using initial mode 2560x1440 on pipe 1
[     5.024] (**) intel(0): TearFree enabled
[     5.024] (==) intel(0): Using gamma correction (1.0, 1.0, 1.0)
[     5.024] (==) intel(0): DPI set to (96, 96)
[     5.026] (II) intel(0): SNA initialized with Kabylake (gen9) backend
[     5.026] (==) intel(0): Backing store enabled
[     5.026] (==) intel(0): Silken mouse disabled
[     5.026] (II) intel(0): HW Cursor enabled
[     5.026] (==) intel(0): DPMS enabled
[     5.026] (==) intel(0): Display hotplug detection enabled
[     5.027] (II) intel(0): [DRI2] Setup complete
[     5.027] (II) intel(0): [DRI2]   DRI driver: i965
[     5.027] (II) intel(0): [DRI2]   VDPAU driver: va_gl
[     5.027] (II) intel(0): direct rendering: DRI2 DRI3 enabled
[     5.027] (II) intel(0): hardware support for Present enabled
[     5.086] (II) intel(0): switch to mode 1920x1080@60.0 on eDP1 using pipe 0, position (0, 0), rotation normal, reflection none
[     5.088] (II) intel(0): switch to mode 2560x1440@60.0 on HDMI1 using pipe 1, position (0, 0), rotation normal, reflection none
[     5.103] (II) intel(0): Setting screen physical size to 677 x 381
[     7.028] (II) intel(0): EDID vendor "AUO", prod id 12605
[     7.028] (II) intel(0): Printing DDC gathered Modelines:
[     7.028] (II) intel(0): Modeline "1920x1080"x0.0  141.00  1920 1936 1952 2104  1080 1083 1097 1116 -hsync -vsync (67.0 kHz eP)
[     7.363] (--) intel(0): HDMI max TMDS frequency 250000KHz
[    20.857] (--) intel(0): HDMI max TMDS frequency 250000KHz
[    21.032] (--) intel(0): HDMI max TMDS frequency 250000KHz
[    21.586] (II) intel(0): resizing framebuffer to 4480x1440
[    21.635] (II) intel(0): switch to mode 2560x1440@60.0 on HDMI1 using pipe 1, position (1920, 0), rotation normal, reflection none


Relevant-ish pkg installed (pacman -Q | grep -E 'plasma|kde|qt5|xorg|^k'   ... not sure if there's a better way to do this):

kaccounts-integration 20.12.1-1
kactivities 5.78.0-1
kactivities-stats 5.78.0-1
kactivitymanagerd 5.20.5-1
karchive 5.78.0-1
kauth 5.78.0-1
kbd 2.3.0-2
kbookmarks 5.78.0-1
kcmutils 5.78.0-1
kcodecs 5.78.0-1
kcolorpicker 0.1.5-1
kcompletion 5.78.0-2
kconfig 5.78.0-1
kconfigwidgets 5.78.0-1
kcoreaddons 5.78.0-1
kcrash 5.78.0-1
kdbusaddons 5.78.0-1
kde-cli-tools 5.20.5-1
kdeclarative 5.78.0-1
kdecoration 5.20.5-1
kded 5.78.0-1
kdelibs4support 5.78.0-1
kdesu 5.78.0-1
kdnssd 5.78.0-1
kdsoap 1.10.0-1
kdsoap-ws-discovery-client git20200927-1
kemoticons 5.78.0-1
keyutils 1.6.3-1
kfilemetadata 5.78.0-1
kglobalaccel 5.78.0-1
kguiaddons 5.78.0-1
kholidays 1:5.78.0-1
khotkeys 5.20.5-1
ki18n 5.78.0-1
kiconthemes 5.78.0-1
kidletime 5.78.0-1
kimageannotator 0.4.0-2
kinit 5.78.0-1
kio 5.78.0-3
kio-extras 20.12.1-1
kirigami2 5.78.0-1
kitemmodels 5.78.0-1
kitemviews 5.78.0-1
kjobwidgets 5.78.0-1
kmenuedit 5.20.5-1
kmod 28-1
knewstuff 5.78.0-1
knotifications 5.78.0-1
knotifyconfig 5.78.0-1
konsole 20.12.1-1
kpackage 5.78.0-1
kparts 5.78.0-1
kpeople 5.78.0-1
kpty 5.78.0-1
kquickcharts 5.78.0-1
krb5 1.18.3-1
krunner 5.78.0-1
kscreen 5.20.5-1
kscreenlocker 5.20.5-1
kservice 5.78.0-1
ksysguard 5.20.5-1
ktexteditor 5.78.0-1
ktextwidgets 5.78.0-1
kunitconversion 5.78.0-1
kuserfeedback 1.0.0-1
kwallet 5.78.0-1
kwallet-pam 5.20.5-1
kwayland 5.78.0-1
kwayland-server 5.20.5-1
kwidgetsaddons 5.78.0-1
kwin 5.20.5-1
kwindowsystem 5.78.0-1
kxmlgui 5.78.0-1
libblockdev 2.25-1
libdbusmenu-qt5 0.9.3+16.04.20160218-5
phonon-qt5 4.11.1-2
phonon-qt5-gstreamer 4.10.0-2
plasma-desktop 5.20.5-2
plasma-framework 5.78.0-1
plasma-integration 5.20.5-1
plasma-nm 5.20.5-1
plasma-pa 5.20.5-1
plasma-workspace 5.20.5-2
polkit-kde-agent 5.20.5-1
polkit-qt5 0.113.0-2
poppler-qt5 21.02.0-1
python-pyqt5 5.15.2-3
python-pyqt5-sip 12.8.1-3
python-pyqt5-webengine 5.15.2-1
qt5-base 5.15.2-3
qt5-declarative 5.15.2-1
qt5-graphicaleffects 5.15.2-1
qt5-location 5.15.2-2
qt5-multimedia 5.15.2-1
qt5-quickcontrols 5.15.2-1
qt5-quickcontrols2 5.15.2-1
qt5-script 5.15.2-1
qt5-sensors 5.15.2-1
qt5-speech 5.15.2-1
qt5-svg 5.15.2-1
qt5-tools 5.15.2-2
qt5-wayland 5.15.2-1
qt5-webchannel 5.15.2-1
qt5-webengine 5.15.2-5
qt5-webkit 5.212.0alpha4-9
qt5-x11extras 5.15.2-1
xorg-bdftopcf 1.1-2
xorg-fonts-encodings 1.0.5-2
xorg-iceauth 1.0.8-2
xorg-mkfontscale 1.2.1-2
xorg-server 1.20.10-3
xorg-server-common 1.20.10-3
xorg-sessreg 1.1.2-2
xorg-setxkbmap 1.3.2-2
xorg-smproxy 1.0.6-3
xorg-x11perf 1.6.1-2
xorg-xauth 1.1-2
xorg-xbacklight 1.2.3-2
xorg-xcmsdb 1.0.5-3
xorg-xcursorgen 1.0.7-2
xorg-xdpyinfo 1.3.2-4
xorg-xdriinfo 1.0.6-2
xorg-xev 1.2.4-1
xorg-xgamma 1.0.6-3
xorg-xhost 1.0.8-2
xorg-xinit 1.4.1-3
xorg-xinput 1.6.3-2
xorg-xkbcomp 1.4.4-1
xorg-xkbevd 1.1.4-3
xorg-xkbutils 1.0.4-4
xorg-xkill 1.0.5-2
xorg-xlsatoms 1.1.3-2
xorg-xlsclients 1.1.4-2
xorg-xmessage 1.0.5-2
xorg-xmodmap 1.0.10-2
xorg-xpr 1.0.5-2
xorg-xprop 1.2.5-1
xorg-xrandr 1.5.1-2
xorg-xrdb 1.2.0-2
xorg-xrefresh 1.0.6-2
xorg-xset 1.2.4-2
xorg-xsetroot 1.1.2-2
xorg-xvinfo 1.1.4-2
xorg-xwd 1.0.7-2
xorg-xwininfo 1.1.5-2
xorg-xwud 1.0.5-2
xorgproto 2020.1-1

This issue affects me as well, in exactly the same form as described by jean in comment #18. I've had this issue for a long time and haven't ever bothered looking into it before. I can collect information if desired.

I am on Gentoo, Intel graphics, multiple displays. As mentioned above, the clocks are often different on the two displays, and a `kill -9` knocks it loose again. I also occasionally have to kill and restart plasmashell and kwin_x11, which feels related, but I can't say for certain.

FWIW:
Excerpt from glxinfo:
Extended renderer info (GLX_MESA_query_renderer):
    Vendor: Intel (0x8086)
    Device: Mesa Intel(R) UHD Graphics 630 (CFL GT2) (0x3e9b)
    Version: 22.0.3
    Accelerated: yes
    Video memory: 3072MB
    Unified memory: yes

Versions:
kded5 5.92.0
kwin 5.24.5

*** Bug 451897 has been marked as a duplicate of this bug. ***

I suppose there's a chance that Bug 409226 could automatically fix this.

*** Bug 460353 has been marked as a duplicate of this bug. ***

*** Bug 437520 has been marked as a duplicate of this bug. ***

*** Bug 442736 has been marked as a duplicate of this bug. ***

I have this since I just updated from Kubuntu 22.04 to 22.10. I have multiple machine all with Intel gfx but this is the only one with dual monitors. Not sure if it is related to dual monitors or if I missed updating some conf file during the update.

I have been monitoring processes (htop) and logs (journalctl) on the console (crtl-alt F2),  but nothing seems to be consuming lots of cpu or spitting sensible messages. Switching to console and back after I typed the password does make the screen onlock.

*** Bug 465113 has been marked as a duplicate of this bug. ***

Created attachment 156229 [details]
gdb backtrace

coming from Bug 465113, hopefully this is somewhat helpful

It mostly shows that the NVIDIA driver is involved. Beyond that, I can't tell. But the issue doesn't seem NVIDIA-specific, as people with Intel GPUs and open-source Mesa drivers have reported experiencing it too.

Hello,

I have 2 laptops on Debian testing (plasma 5.26.90-1, qt 5.15.8+dfsg-2), that regularly fail to unlock after sleep (but not always, haven't identified the exact situation yet).
Here is a journalctl extract that seems relevant (note the "kernel: traps: kscreenlocker_g"):

21:30:03 plasmashell[1236]: qt.qpa.wayland: Wayland does not support QWindow::requestActivate()
21:30:03 plasmashell[1236]: qt.qpa.wayland: Wayland does not support QWindow::requestActivate()
21:30:03 plasmashell[1236]: Checking screens: available: (QScreen(0x56222c70e3a0, name="HDMI-A-1")) redundant: QHash() fake: QSet() all: (QScreen(0x56222a3c13e0, name="eDP-1"), QScreen(0x56222c70e3a0, name="HDMI-A->
21:30:03 plasmashell[1236]: file:///usr/share/plasma/wallpapers/org.kde.image/contents/ui/main.qml:20: TypeError: Cannot read property 'pluginName' of null
21:30:03 plasmashell[1236]: file:///usr/share/plasma/wallpapers/org.kde.image/contents/ui/main.qml:75: TypeError: Cannot read property 'configuration' of null
21:30:03 plasmashell[1236]: file:///usr/share/plasma/wallpapers/org.kde.image/contents/ui/main.qml:78: TypeError: Cannot read property 'pluginName' of null
21:30:03 plasmashell[1236]: file:///usr/share/plasma/wallpapers/org.kde.image/contents/ui/main.qml:80: TypeError: Cannot read property 'configuration' of null
21:30:03 plasmashell[1236]: file:///usr/share/plasma/wallpapers/org.kde.image/contents/ui/main.qml:81: TypeError: Cannot read property 'configuration' of null
21:30:03 plasmashell[1236]: file:///usr/share/plasma/wallpapers/org.kde.image/contents/ui/main.qml:82: TypeError: Cannot read property 'configuration' of null
21:30:03 plasmashell[1236]: file:///usr/share/plasma/wallpapers/org.kde.image/contents/ui/main.qml:83: TypeError: Cannot read property 'configuration' of null
21:30:03 plasmashell[1236]: file:///usr/share/plasma/wallpapers/org.kde.image/contents/ui/main.qml:84: TypeError: Cannot read property 'configuration' of null
21:30:03 plasmashell[1236]: file:///usr/share/plasma/wallpapers/org.kde.image/contents/ui/main.qml:16: TypeError: Cannot read property 'configuration' of null
21:30:03 plasmashell[1236]: file:///usr/share/plasma/wallpapers/org.kde.image/contents/ui/main.qml:17: TypeError: Cannot read property 'configuration' of null
21:30:03 plasmashell[1236]: file:///usr/share/plasma/wallpapers/org.kde.image/contents/ui/main.qml:18: TypeError: Cannot read property 'configuration' of null
21:30:03 bluetoothd[733]: profiles/sap/server.c:sap_server_register() Sap driver initialization failed.
21:30:03 bluetoothd[733]: sap-server: Operation not permitted (1)
21:30:03 kernel: Bluetooth: MGMT ver 1.22
21:30:03 bluetoothd[733]: Failed to set mode: Failed (0x03)
21:30:03 org_kde_powerdevil[14410]: Initializing  "/usr/lib/x86_64-linux-gnu/qt5/plugins/plasma/kcms/systemsettings/kcm_fonts.so"
21:30:03 kernel: traps: kscreenlocker_g[14218] general protection fault ip:7fa918e8bff4 sp:7ffd482882b8 error:0 in libQt5Qml.so.5.15.8[7fa918ca0000+2f1000]
21:30:03 org_kde_powerdevil[14416]: Initializing  "/usr/lib/x86_64-linux-gnu/qt5/plugins/plasma/kcms/systemsettings/kcm_fonts.so"
21:30:03 kded5[14411]: Initializing  "/usr/lib/x86_64-linux-gnu/qt5/plugins/plasma/kcms/systemsettings/kcm_fonts.so"
21:30:03 plasmashell[1236]: file:///usr/share/plasma/plasmoids/org.kde.plasma.bluetooth/contents/ui/FullRepresentation.qml:133:13: QML Loader: Possible anchor loop detected on centerIn.
21:30:03 plasmashell[14422]: Initializing  "/usr/lib/x86_64-linux-gnu/qt5/plugins/plasma/kcms/systemsettings/kcm_fonts.so"
21:30:03 kded5[14424]: Initializing  "/usr/lib/x86_64-linux-gnu/qt5/plugins/plasma/kcms/systemsettings/kcm_fonts.so"
21:30:03 plasmashell[14430]: Initializing  "/usr/lib/x86_64-linux-gnu/qt5/plugins/plasma/kcms/systemsettings/kcm_fonts.so"
21:30:03 kwin_wayland_wrapper[1111]: not a valid new object id (2), message get_registry(n)
21:30:03 kwin_wayland_wrapper[1111]: error in client communication (pid 1111)
21:30:03 kwin_wayland_wrapper[14449]: error: received delete_id for unknown id (43)
21:30:03 kwin_wayland_wrapper[14449]: error: received delete_id for unknown id (47)
21:30:03 kwin_wayland_wrapper[14449]: error: received delete_id for unknown id (44)
21:30:03 kwin_wayland_wrapper[14449]: error: received delete_id for unknown id (45)
21:30:03 kwin_wayland_wrapper[14449]: error: received delete_id for unknown id (39)
21:30:03 kwin_wayland_wrapper[14449]: error: received delete_id for unknown id (53)
21:30:03 kwin_wayland_wrapper[14449]: error: received delete_id for unknown id (38)
21:30:03 kwin_wayland_wrapper[14449]: error: received delete_id for unknown id (41)
21:30:03 kwin_wayland_wrapper[14449]: error: received delete_id for unknown id (19)
21:30:03 kwin_wayland_wrapper[14449]: error: received delete_id for unknown id (18)
21:30:03 kwin_wayland_wrapper[14449]: wl_display@1: error 1: invalid arguments for wl_display@1.get_registry
21:30:03 kwin_wayland_wrapper[14449]: The Wayland connection experienced a fatal error: Argument invalide
21:30:03 kwin_wayland_wrapper[14449]: qt.qpa.wayland: Creating a fake screen in order for Qt not to crash
21:30:03 kwin_wayland_wrapper[14459]: qt.qpa.wayland: Creating a fake screen in order for Qt not to crash
21:30:03 kwin_wayland_wrapper[14459]: The Wayland connection broke. Did the Wayland compositor die?
21:30:03 kwin_wayland_wrapper[14462]: qt.qpa.wayland: Creating a fake screen in order for Qt not to crash
21:30:03 kwin_wayland_wrapper[14462]: The Wayland connection broke. Did the Wayland compositor die?
21:30:04 bluetoothd[733]: Failed to set mode: Failed (0x03)
21:30:04 kded5[1197]: kf.bluezqt: PendingCall Error: "Failed"

Please let me know what kind of extra info I can give to help. I'm also waiting for latest release to hit debian-12...

Good luck!

I'm observing the same issue for something like 1-2 YEARS. Now I'm killing it with -9 multiple times a day :-/.
If I remember correctly it started when Intel replaced the old driver with Iris. But I'm not sure 100%, maybe it reproduced even before it.
Please fix it at last...)

By the way, I don't use a multiscreen setup - for me it reproduces on a laptop without the external monitor, and with Intel integrated graphics (I also have nvidia proprietary driver installed but I don't think it's related to it).

    Vendor: Intel (0x8086)
    Device: Mesa Intel(R) HD Graphics 530 (SKL GT2) (0x191b)
    Version: 22.3.5
    Accelerated: yes
    Video memory: 15889MB

Is it still occurring with plasma 5.27.x? Some similar bugs got resolved with this release

(In reply to Simon B from comment #34)
> Is it still occurring with plasma 5.27.x? Some similar bugs got resolved
> with this release

Thanks for the information, I just installed 5.27.2, will check if the bug still persists

I almost thought it was fixed :) but it reproduced with 5.27.2 again, after a day of usage. :) I tend to think that it's still slightly better because today I only had to kill -9 it one time instead of several times as it was with <= 5.26.90... But it seems the bug is still there

(In reply to Vincent PINON from comment #29)
> I have 2 laptops on Debian testing (plasma 5.26.90-1, qt 5.15.8+dfsg-2),
> that regularly fail to unlock after sleep (but not always, haven't
> identified the exact situation yet).
> Here is a journalctl extract that seems relevant (note the "kernel: traps:
> kscreenlocker_g"):

The error occurred several times again, and actually "kscreenlocker" line doesn't appear every time in journalctl, whereas kwin_wayland failure is always here.
It was still on 5.26.90 (latest available in Debian testing) ; I'm installing 5.27.2 from Debian unstable, will see in the next days and let you know...
Thanks!

In fact it hasn't reproduced for me more since that 1 time. So it seems that it's almost fixed. Only 1 failure in 5 days with 5.27.2 by now :)

Created attachment 157143 [details]
Stack traces of hung kscreenlocker_greet

Ok, finally I got another hang with 5.27.2. Attaching stack traces of all threads...

Seems that it still hangs when compositing is disabled, yeah.

Unfortunately that backtrace isn't terribly useful. Please check https://community.kde.org/Guidelines_and_HOWTOs/Debugging/How_to_create_useful_crash_reports#Install_debugging_packages

Ok, I can do that, the bug still reproduces almost every time when compositing is disabled

Works fine for me :|

> The error occurred several times again, and actually "kscreenlocker" line
> doesn't appear every time in journalctl, whereas kwin_wayland failure is
> always here.
> It was still on 5.26.90 (latest available in Debian testing) ; I'm
> installing 5.27.2 from Debian unstable, will see in the next days and let
> you know...

I forgot to report back: I still had the crash with plasma 5.27.2.
It is always in kwin_wayland, so *not this bug*.
Since then I reverted to X11 session to avoid this annoyance, so I don't track the problem anymore, sorry.

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
mark the bug 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!

Created attachment 158888 [details]
hung kscreenlocker stack traces with debug info

Thanks! Looks like two kscreenlocker_greet processes are running and one is stuck in a futex while the other is in a pselect64 syscall. Maybe they're blocking one another.

I don't think there are 2 of them... I always check processes with `ps ax|grep kscr` when I'm killing a stuck kscreenlocker_greet and I always see 2 processes:
1) /usr/lib/x86_64-linux-gnu/libexec/kf5/kscreen_backend_launcher
2) kscreenlocker_greet
And I always kill the second one after which it restarts and I log back in :)
So maybe threads lock each other, but not processes...

I'm getting this now, and I do see two instances of kscreenlocker_greet. I also see plasmashell and dolphin using high CPU at the same time.

Next time it occurs I'll kill one and see if that solves for the other.

An easy way to unlock the screen if the locker freezes as root is:
loginctl unlock-sessions.

An issue I've been having for a long time with the locker with a dual monitor setup is that if I try to unlock immediately as it attempts to lock the screen, there is a high probability that the displays will freeze empty, only the mouse cursor will be visible and if I move the mouse cursor to the primary monitor, it will be leaving a trail of mouse cursors behind, which has limited length, i.e. the more I move the mouse, the older parts of the trail are erased. loginctl unlock-sessions does nothing when this occurs, I can only restart the session. I'm not certain it is the same issue as this one, though.

Killing one is working for me, but it's not a great solution. To minimise hassle one could write a script to kill the first process if there are multiple and run it as a cron job every second, but that's obviously not ideal.

I'm also seeing this on Ubuntu, not Arch. But generally only after resuming, not just from locking, and not consistently.

I think I made a mistake marking all of those bugs as duplicates of this one, as on second look, they're all subtly different from what was reported here. I'll un-dupe them and triage them separately. The good news is that the issue described here is now fixed in Plasma 6 with a variety of KScreenLocker changes.