Application: kwin_x11 (5.12.6) Qt Version: 5.9.5 Frameworks Version: 5.44.0 Operating System: Linux 4.15.0-34-generic x86_64 Distribution: Ubuntu 18.04.1 LTS -- Information about the crash: Windows lose titlebar; I cannot change the focus with the mouse or with ALT-tab; the focused application is not responsive to the keyboard or the mouse; mouse is the only think moving; some lost titlebar usually allows mouse access to the desktop background and I can right-click and select Execute command... to run kwin --replace, which restores normal functionality. If I remember correctly, I can also go to a terminal, with CTRL-ALT-F1/F2 etc during the crash. Windows from all activities appear in a single activity, but retain their virtual desktop, on restore from the crash --I cannot say if this is also the case during the crash. - What I was doing when the application crashed: The crash happens repeatedly, when changing virtual desktop, using the keyboard shortcut (CTRL-ALT-left/right/up/down arrow). Usually, after I have been viewing idly a window for some time; more frequently when I was viewing idly for more than a minut, but it also happens after only 5-10 seconds sometimes. The crash can be reproduced sometimes. -- Backtrace: Application: KWin (kwin_x11), signal: Segmentation fault Using host libthread_db library "/lib/x86_64-linux-gnu/libthread_db.so.1". [Current thread is 1 (Thread 0x7ff0a4aa7cc0 (LWP 9737))] Thread 3 (Thread 0x7fefb9f12700 (LWP 9749)): #0 0x00007ff09d4739f3 in futex_wait_cancelable (private=<optimized out>, expected=0, futex_word=0x7ff0a0a0afb8) at ../sysdeps/unix/sysv/linux/futex-internal.h:88 #1 0x00007ff09d4739f3 in __pthread_cond_wait_common (abstime=0x0, mutex=0x7ff0a0a0af68, cond=0x7ff0a0a0af90) at pthread_cond_wait.c:502 #2 0x00007ff09d4739f3 in __pthread_cond_wait (cond=0x7ff0a0a0af90, mutex=0x7ff0a0a0af68) at pthread_cond_wait.c:655 #3 0x00007ff0a07145f4 in () at /usr/lib/x86_64-linux-gnu/libQt5Script.so.5 #4 0x00007ff0a0714639 in () at /usr/lib/x86_64-linux-gnu/libQt5Script.so.5 #5 0x00007ff09d46d6db in start_thread (arg=0x7fefb9f12700) at pthread_create.c:463 #6 0x00007ff0a441388f in clone () at ../sysdeps/unix/sysv/linux/x86_64/clone.S:95 Thread 2 (Thread 0x7ff088847700 (LWP 9739)): #0 0x00007ffc4dd1ab62 in clock_gettime () #1 0x00007ff0a4422ea6 in __GI___clock_gettime (clock_id=1, tp=0x7ff088846b80) at ../sysdeps/unix/clock_gettime.c:115 #2 0x00007ff0a180c221 in () at /usr/lib/x86_64-linux-gnu/libQt5Core.so.5 #3 0x00007ff0a180aa59 in QTimerInfoList::updateCurrentTime() () at /usr/lib/x86_64-linux-gnu/libQt5Core.so.5 #4 0x00007ff0a180b035 in QTimerInfoList::timerWait(timespec&) () at /usr/lib/x86_64-linux-gnu/libQt5Core.so.5 #5 0x00007ff0a1809fe4 in QEventDispatcherUNIX::processEvents(QFlags<QEventLoop::ProcessEventsFlag>) () at /usr/lib/x86_64-linux-gnu/libQt5Core.so.5 #6 0x00007ff0a17b19ea in QEventLoop::exec(QFlags<QEventLoop::ProcessEventsFlag>) () at /usr/lib/x86_64-linux-gnu/libQt5Core.so.5 #7 0x00007ff0a15d022a in QThread::exec() () at /usr/lib/x86_64-linux-gnu/libQt5Core.so.5 #8 0x00007ff09ae32d45 in () at /usr/lib/x86_64-linux-gnu/libQt5DBus.so.5 #9 0x00007ff0a15d516d in () at /usr/lib/x86_64-linux-gnu/libQt5Core.so.5 #10 0x00007ff09d46d6db in start_thread (arg=0x7ff088847700) at pthread_create.c:463 #11 0x00007ff0a441388f in clone () at ../sysdeps/unix/sysv/linux/x86_64/clone.S:95 Thread 1 (Thread 0x7ff0a4aa7cc0 (LWP 9737)): [KCrash Handler] #6 0x00007ff0a3f9322d in KWin::Xcb::Extensions::init() () at /usr/lib/x86_64-linux-gnu/libkwin.so.5 #7 0x00007ff0a3f93ad7 in KWin::Xcb::Extensions::self() () at /usr/lib/x86_64-linux-gnu/libkwin.so.5 #8 0x00007ff0a3f03a8a in KWin::Application::updateX11Time(xcb_generic_event_t*) () at /usr/lib/x86_64-linux-gnu/libkwin.so.5 #9 0x00007ff0a3f03b32 in () at /usr/lib/x86_64-linux-gnu/libkwin.so.5 #10 0x00007ff0a17b058f in QAbstractEventDispatcher::filterNativeEvent(QByteArray const&, void*, long*) () at /usr/lib/x86_64-linux-gnu/libQt5Core.so.5 #11 0x00007ff08c005820 in QXcbConnection::handleXcbEvent(xcb_generic_event_t*) () at /usr/lib/x86_64-linux-gnu/libQt5XcbQpa.so.5 #12 0x00007ff08c0064ac in QXcbConnection::processXcbEvents() () at /usr/lib/x86_64-linux-gnu/libQt5XcbQpa.so.5 #13 0x00007ff0a17e3122 in QObject::event(QEvent*) () at /usr/lib/x86_64-linux-gnu/libQt5Core.so.5 #14 0x00007ff0a253182c in QApplicationPrivate::notify_helper(QObject*, QEvent*) () at /usr/lib/x86_64-linux-gnu/libQt5Widgets.so.5 #15 0x00007ff0a25390f4 in QApplication::notify(QObject*, QEvent*) () at /usr/lib/x86_64-linux-gnu/libQt5Widgets.so.5 #16 0x00007ff0a17b39a8 in QCoreApplication::notifyInternal2(QObject*, QEvent*) () at /usr/lib/x86_64-linux-gnu/libQt5Core.so.5 #17 0x00007ff0a17b611d in QCoreApplicationPrivate::sendPostedEvents(QObject*, int, QThreadData*) () at /usr/lib/x86_64-linux-gnu/libQt5Core.so.5 #18 0x00007ff0a1809af4 in QEventDispatcherUNIX::processEvents(QFlags<QEventLoop::ProcessEventsFlag>) () at /usr/lib/x86_64-linux-gnu/libQt5Core.so.5 #19 0x00007ff08c0675cd in () at /usr/lib/x86_64-linux-gnu/libQt5XcbQpa.so.5 #20 0x00007ff0a17b19ea in QEventLoop::exec(QFlags<QEventLoop::ProcessEventsFlag>) () at /usr/lib/x86_64-linux-gnu/libQt5Core.so.5 #21 0x00007ff0a17baa84 in QCoreApplication::exec() () at /usr/lib/x86_64-linux-gnu/libQt5Core.so.5 #22 0x00007ff0a46ebdbb in kdemain () at /usr/lib/x86_64-linux-gnu/libkdeinit5_kwin_x11.so #23 0x00007ff0a4313b97 in __libc_start_main (main=0x55a089d2b730, argc=2, argv=0x7ffc4dc50a18, init=<optimized out>, fini=<optimized out>, rtld_fini=<optimized out>, stack_end=0x7ffc4dc50a08) at ../csu/libc-start.c:310 #24 0x000055a089d2b76a in _start () Possible duplicates by query: bug 352971. Reported using DrKonqi
I had another crash, just hours after the original report. This time an application (claws-mail) from another activity and a different virtual desktop number, showed up in the task manager. When I clicked on it, kwin crashed.
Unfortunately the backtrace lacks debug symbols. Could you please install debug packages and submit a new backtrace?
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!
I cannot send an updated backtrace because KDE Crash Dialog does not appear again. Your link for howto get symbols for the backtrace is wrong. I had to read a useless page (since I am not classifying this bug, just reporting it) to get to https://community.kde.org/Guidelines_and_HOWTOs/Debugging/How_to_create_useful_crash_reports, which instructs on how to get debug symbols. I found out I need to install kdelibs5-dbg. I do not know if I need to install symbols for kwin and which packages to install (kwin does not have any -dbg package available). Still I cannot produce and send a backtrace, if KDE Crash Dialog does not appear . kwin still crashes, after a few desktop changes. It is likely that the cube desktop switch effect and the multiple windows in multiple activities I have running, do not interoperate correctly, but I cannot tell you anything more. What should I do with this bug? Going back to Kubuntu 16.04 is my best alternative.
According to https://launchpad.net/ubuntu/+source/kwin, you probably need to install kwin-common-dbgsym (take my words with a grain of salt, I have no idea how Ubuntu folks package things; I suggest to ask Ubuntu folks what debug packages to install) Regarding debugging, you would need to ssh from another machine, see https://community.kde.org/KWin/Debugging I hope it will help you. :-)
I found that kwin_x11 symbols are included in the kwin package. I followed the instructions in the page you mention, using gdb from a remote ssh terminal (from my laptop to the desktop). I tried twice to get the backtrace via gdb. The first time there was a kwin process running and no kwin_x11 and the next time the other way round. There has been an update of kwin and plasma packages in-between, but both times gdb cannot provide a backtrace. The first time I was not sure what happened; I provide the output of the second try, bellow. As you will see, it appears kwin_x11 exits normally(!!!) and I cannot get a backtrace. Here is the output of the command used, i.e. gdb --pid `pidof kwin_x11` 2>&1 | tee kwin_x11.gdb ----------- GNU gdb (Ubuntu 8.1-0ubuntu3) 8.1.0.20180409-git Copyright (C) 2018 Free Software Foundation, Inc. License GPLv3+: GNU GPL version 3 or later <http://gnu.org/licenses/gpl.html> This is free software: you are free to change and redistribute it. There is NO WARRANTY, to the extent permitted by law. Type "show copying" and "show warranty" for details. This GDB was configured as "x86_64-linux-gnu". Type "show configuration" for configuration details. For bug reporting instructions, please see: <http://www.gnu.org/software/gdb/bugs/>. Find the GDB manual and other documentation resources online at: <http://www.gnu.org/software/gdb/documentation/>. For help, type "help". Type "apropos word" to search for commands related to "word". Attaching to process 2460 [New LWP 2462] [New LWP 2480] [New LWP 2542] [New LWP 2637] [New LWP 2652] [Thread debugging using libthread_db enabled] Using host libthread_db library "/lib/x86_64-linux-gnu/libthread_db.so.1". 0x00007f13b1348cf6 in __GI_ppoll (fds=0x5574122160c8, nfds=5, timeout=<optimized out>, sigmask=0x0) at ../sysdeps/unix/sysv/linux/ppoll.c:39 39 ../sysdeps/unix/sysv/linux/ppoll.c: No such file or directory. (gdb) c Continuing. [New Thread 0x7f1379ff7700 (LWP 4603)] [Thread 0x7f1379185700 (LWP 2637) exited] [Thread 0x7f1395788700 (LWP 2480) exited] [Thread 0x7f1379ff7700 (LWP 4603) exited] [Thread 0x7f1370f69700 (LWP 2652) exited] [Thread 0x7f138f5e0700 (LWP 2542) exited] [Thread 0x7f13b19e9cc0 (LWP 2460) exited] [Inferior 1 (process 2460) exited with code 01] (gdb) bt No stack. (gdb) detach The program is not being run. (gdb) run Starting program: /usr/bin/kwin_x11 [Thread debugging using libthread_db enabled] Using host libthread_db library "/lib/x86_64-linux-gnu/libthread_db.so.1". /usr/bin/kwin_x11: FATAL ERROR while trying to open display [Inferior 1 (process 10196) exited with code 01] (gdb) quit
Just to make it clear, kwin_x11 exits without a logout and windows are still visible, but non-responsive. This seems wrong to me, or kwin_x11 process received a signal, which I cannot monitor, unless you guide me on how to instruct gdb to catch such an event...
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!
After you installed kwin debug packages, attach to kwin_x11 and try to reproduce the crash (by switching between virtual desktops). When kwin has crashed, run `(gdb) backtrace` and post the backtrace here.
Please read the whole (short) history of these comments. I cannot do what you ask any more. The crash does not trigger the KDE Crash Dialog to appear, after there has been an update of kwin and plasma packages. The crash still persists but, according to my efforts to provide a gdb backtrace, kwin exits normally and there can be no backtrace! Unless you can guide me on how to monitor with gdb any signals kwin may be receiving before it exits, I cannot provide the backtrace asked. In my opinion, you should try to debug this differently, as the last update has hidden a bug that once led to a crash, so that it now exits normally. How can this bug ever be reported and corrected now, if you require a backtrace? Nevertheless, if you cannot reproduce the bug, I understand you do not have a place to start. But, this would leave me no option, but to go back to Kubuntu 16.04, which did not have this problem.
(In reply to Stamatis Kavvadias from comment #11) > The crash does not trigger the KDE Crash Dialog to appear You don't have to use that to get a backtrace. > Unless you can guide me on how I already told you how to get a backtrace, you attach to kwin_x11, make kwin crash, and then run `(gdb) backtrace`. > How can this bug ever be reported and corrected now, if you require a > backtrace? This is a standard requirement for crash bug reports. For us, it can be hard to reproduce bugs, backtraces help a lot to understand what went wrong.
Listen, I am sorry if I was not clear enough (but you also did not check my previous efforts to provide a backtrace). The case is that, since I provided the initial backtrace (w/o debug symbols), I have accepted an update which changed the situation: I no longer have a version of kwin (or kwin_x11) that crashes from the bug. Instead, my current kwin version just exits normally when the bug happens. This update happened exactly before I tried to attach gdb to kwin, so when I did the result was that gdb *could not* provide a backtrace. I have provided the output of gdb in this case, which explains clearly why. So, tell me something new to do or just delete this bug report, if it cannot be handled, under the circumstances. Thank you for your efforts, anyway.
(In reply to Stamatis Kavvadias from comment #13) > Instead, my current kwin version just exits normally when the bug happens. If the bug is still present, KWin *should* crash. If KWin doesn't crash, then there is no bug (or it was fixed).