If something crashed, we need a backtrace of it so we can figure out what's going on. See https://community.kde.org/Guidelines_and_HOWTOs/Debugging/How_to_create_useful_crash_reports.

You may be able to get one with `coredumpctl gdb 571843` and then type `bt` and then the enter key.

Can you please attach a backtrace? Thanks!

(In reply to Nate Graham from comment #1)
> If something crashed, we need a backtrace of it so we can figure out what's
> going on. See
> https://community.kde.org/Guidelines_and_HOWTOs/Debugging/
> How_to_create_useful_crash_reports.
> 
> You may be able to get one with `coredumpctl gdb 571843` and then type `bt`
> and then the enter key.
> 
> Can you please attach a backtrace? Thanks!

Unfortunately I can't, it is not available. I didn't have coredumpctl installed; now I do, but it says there are no coredumps available.

Then I'm afraid there is no way to debug this unless you can make it happen again and attach a backtrace.

In general, crash reports must include backtraces to be actionable or else unfortunately they're just a waste of everyone's time, yours included. ;)

Well, Plasma crashes and doesn't leave anything in coredumpctl. KDE's own crash handler shows this:
[New LWP 736766]
[New LWP 736768]
[New LWP 736769]
[New LWP 736770]
[New LWP 736771]
[New LWP 736772]
[New LWP 736773]
[New LWP 736774]
[New LWP 736775]
[New LWP 736776]
[New LWP 736777]
[New LWP 736778]
[New LWP 736779]
[New LWP 736781]
[New LWP 736782]
[New LWP 736786]
[New LWP 736787]
[New LWP 736788]
[New LWP 736808]
[New LWP 736830]
[New LWP 736951]
[New LWP 736952]
[New LWP 737014]
[New LWP 737027]
[New LWP 737028]
[Thread debugging using libthread_db enabled]
Using host libthread_db library "/lib/x86_64-linux-gnu/libthread_db.so.1".
0x00007f10ab12099f in __GI___poll (fds=0x7ffe7b5eed78, nfds=1, timeout=1000) at ../sysdeps/unix/sysv/linux/poll.c:29
python sentry-sdk not installed :(

/build/gdb-p9IBCp/gdb-10.2/gdb/findvar.c:210: internal-error: store_typed_address: type is not a pointer or reference
A problem internal to GDB has been detected,
further debugging may prove unreliable.
Quit this debugging session? (y or n) [answered Y; input not from terminal]

(which I had to copy manually after trying to generate the crash information multiple times, as the crash handler hides this automatically and just says "the crash information could not be generated". Speaking of wasting time... :) )
Let me know if you have any ideas on how to get a backtrace, I have tried to search the error on Google without finding anything useful.

> /build/gdb-p9IBCp/gdb-10.2/gdb/findvar.c:210: internal-error: store_typed_address: type is not a pointer or reference
Have you built GDB from source? It seems like there is a problem with your build.

No, it's installed from the Ubuntu repos.

I guess there's an issue with Ubuntu's GDB? o_O

Without GDB working, this isn't going to have any chance of success.

Plasma crashed two times, both times when there were multiple notifications and I was closing the top one. This time there was a plasmashell entry in coredumpctl, and GDB worked. Funny thing is, I didn't even reboot since last time. Anyway, here is the backtrace:

                Stack trace of thread 1437070:
                #0  0x00007f843025100b __GI_raise (libc.so.6 + 0x4300b)
                #1  0x00007f8432bc1ff5 _ZN6KCrash19defaultCrashHandlerEi (libKF5Crash.so.5 + 0x5ff5)
                #2  0x00007f8430251090 __restore_rt (libc.so.6 + 0x43090)
                #3  0x00007f8432096e73 _Z13qGetPtrHelperI14QScopedPointerI11QObjectData21QScopedPointerDeleterIS1_EEEDTcldtfp_onptEERT_ (libQt5Qml.so.5 + 0x296e73)
                #4  0x00007f843255046e _ZN16QQuickTransition7prepareER5QListI17QQuickStateActionERS0_I12QQmlPropertyEP23QQuickTransitionManagerP7QObject (libQt5Quick.so.5 + 0x15046e)
                #5  0x00007f843254603f _ZN23QQuickTransitionManager10transitionERK5QListI17QQuickStateActionEP16QQuickTransitionP7QObject (libQt5Quick.so.5 + 0x14603f)
                #6  0x00007f8430ae2c25 _ZN7QObject5eventEP6QEvent (libQt5Core.so.5 + 0x2e2c25)
                #7  0x00007f843176de43 _ZN19QApplicationPrivate13notify_helperEP7QObjectP6QEvent (libQt5Widgets.so.5 + 0x16de43)
                #8  0x00007f8431776c58 _ZN12QApplication6notifyEP7QObjectP6QEvent (libQt5Widgets.so.5 + 0x176c58)
                #9  0x00007f8430ab503a _ZN16QCoreApplication15notifyInternal2EP7QObjectP6QEvent (libQt5Core.so.5 + 0x2b503a)
                #10 0x00007f8430b0eed0 _ZN14QTimerInfoList14activateTimersEv (libQt5Core.so.5 + 0x30eed0)
                #11 0x00007f8430b0f804 timerSourceDispatch (libQt5Core.so.5 + 0x30f804)
                #12 0x00007f842ed4317d g_main_context_dispatch (libglib-2.0.so.0 + 0x5217d)
                #13 0x00007f842ed43400 n/a (libglib-2.0.so.0 + 0x52400)
                #14 0x00007f842ed434a3 g_main_context_iteration (libglib-2.0.so.0 + 0x524a3)
                #15 0x00007f8430b0fb82 _ZN20QEventDispatcherGlib13processEventsE6QFlagsIN10QEventLoop17ProcessEventsFlagEE (libQt5Core.so.5 + 0x30fb82)
                #16 0x00007f8430ab3b3b _ZN10QEventLoop4execE6QFlagsINS_17ProcessEventsFlagEE (libQt5Core.so.5 + 0x2b3b3b)
                #17 0x00007f8430abbce4 _ZN16QCoreApplication4execEv (libQt5Core.so.5 + 0x2bbce4)
                #18 0x000055fc82af37ec n/a (plasmashell + 0x297ec)
                #19 0x00007f8430232083 __libc_start_main (libc.so.6 + 0x24083)
                #20 0x000055fc82af391e n/a (plasmashell + 0x2991e)
                
                Stack trace of thread 1437091:
                #0  0x00007f84322ca376 futex_wait_cancelable (libpthread.so.0 + 0xf376)
                #1  0x00007f84286c3e8b n/a (radeonsi_dri.so + 0xc3e8b)
                #2  0x00007f84286c3bdb n/a (radeonsi_dri.so + 0xc3bdb)
                #3  0x00007f84322c3609 start_thread (libpthread.so.0 + 0x8609)
                #4  0x00007f843032d133 __clone (libc.so.6 + 0x11f133)
                
                Stack trace of thread 1437090:
                #0  0x00007f84322ca376 futex_wait_cancelable (libpthread.so.0 + 0xf376)
                #1  0x00007f84286c3e8b n/a (radeonsi_dri.so + 0xc3e8b)
                #2  0x00007f84286c3bdb n/a (radeonsi_dri.so + 0xc3bdb)
                #3  0x00007f84322c3609 start_thread (libpthread.so.0 + 0x8609)
                #4  0x00007f843032d133 __clone (libc.so.6 + 0x11f133)
                
                Stack trace of thread 1437084:
                #0  0x00007f84322ca376 futex_wait_cancelable (libpthread.so.0 + 0xf376)
                #1  0x00007f84286c3e8b n/a (radeonsi_dri.so + 0xc3e8b)
                #2  0x00007f84286c3bdb n/a (radeonsi_dri.so + 0xc3bdb)
                #3  0x00007f84322c3609 start_thread (libpthread.so.0 + 0x8609)
                #4  0x00007f843032d133 __clone (libc.so.6 + 0x11f133)
                
                Stack trace of thread 1437085:
                #0  0x00007f84322ca376 futex_wait_cancelable (libpthread.so.0 + 0xf376)
                #1  0x00007f84286c3e8b n/a (radeonsi_dri.so + 0xc3e8b)
                #2  0x00007f84286c3bdb n/a (radeonsi_dri.so + 0xc3bdb)
                #3  0x00007f84322c3609 start_thread (libpthread.so.0 + 0x8609)
                #4  0x00007f843032d133 __clone (libc.so.6 + 0x11f133)
                
                Stack trace of thread 1437089:
                #0  0x00007f84322ca376 futex_wait_cancelable (libpthread.so.0 + 0xf376)
                #1  0x00007f84286c3e8b n/a (radeonsi_dri.so + 0xc3e8b)
                #2  0x00007f84286c3bdb n/a (radeonsi_dri.so + 0xc3bdb)
                #3  0x00007f84322c3609 start_thread (libpthread.so.0 + 0x8609)
                #4  0x00007f843032d133 __clone (libc.so.6 + 0x11f133)
                
                Stack trace of thread 1437088:
                #0  0x00007f84322ca376 futex_wait_cancelable (libpthread.so.0 + 0xf376)
                #1  0x00007f84286c3e8b n/a (radeonsi_dri.so + 0xc3e8b)
                #2  0x00007f84286c3bdb n/a (radeonsi_dri.so + 0xc3bdb)
                #3  0x00007f84322c3609 start_thread (libpthread.so.0 + 0x8609)
                #4  0x00007f843032d133 __clone (libc.so.6 + 0x11f133)
                
                Stack trace of thread 1437140:
                #0  0x00007f84322ca7d1 futex_abstimed_wait_cancelable (libpthread.so.0 + 0xf7d1)
                #1  0x00007f84308d4578 _ZN21QWaitConditionPrivate13wait_relativeE14QDeadlineTimer (libQt5Core.so.5 + 0xd4578)
                #2  0x00007f84308d1a91 _ZN17QThreadPoolThread3runEv (libQt5Core.so.5 + 0xd1a91)
                #3  0x00007f84308ce543 _ZN14QThreadPrivate5startEPv (libQt5Core.so.5 + 0xce543)
                #4  0x00007f84322c3609 start_thread (libpthread.so.0 + 0x8609)
                #5  0x00007f843032d133 __clone (libc.so.6 + 0x11f133)
                
                Stack trace of thread 1437316:
                #0  0x00007f84322ca376 futex_wait_cancelable (libpthread.so.0 + 0xf376)
                #1  0x00007f84286c3e8b n/a (radeonsi_dri.so + 0xc3e8b)
                #2  0x00007f84286c3bdb n/a (radeonsi_dri.so + 0xc3bdb)
                #3  0x00007f84322c3609 start_thread (libpthread.so.0 + 0x8609)
                #4  0x00007f843032d133 __clone (libc.so.6 + 0x11f133)
                
                Stack trace of thread 1437317:
                #0  0x00007f84322ca376 futex_wait_cancelable (libpthread.so.0 + 0xf376)
                #1  0x00007f84308d45eb _ZN21QWaitConditionPrivate4waitE14QDeadlineTimer (libQt5Core.so.5 + 0xd45eb)
                #2  0x00007f8432623394 _ZN25QSGRenderThreadEventQueue9takeEventEb (libQt5Quick.so.5 + 0x223394)
                #3  0x00007f8432623809 _ZN15QSGRenderThread3runEv (libQt5Quick.so.5 + 0x223809)
                #4  0x00007f84308ce543 _ZN14QThreadPrivate5startEPv (libQt5Core.so.5 + 0xce543)
                #5  0x00007f84322c3609 start_thread (libpthread.so.0 + 0x8609)
                #6  0x00007f843032d133 __clone (libc.so.6 + 0x11f133)
                
                Stack trace of thread 1437143:
                #0  0x00007f84322ca7d1 futex_abstimed_wait_cancelable (libpthread.so.0 + 0xf7d1)
                #1  0x00007f84308d4578 _ZN21QWaitConditionPrivate13wait_relativeE14QDeadlineTimer (libQt5Core.so.5 + 0xd4578)
                #2  0x00007f84308d1a91 _ZN17QThreadPoolThread3runEv (libQt5Core.so.5 + 0xd1a91)
                #3  0x00007f84308ce543 _ZN14QThreadPrivate5startEPv (libQt5Core.so.5 + 0xce543)
                #4  0x00007f84322c3609 start_thread (libpthread.so.0 + 0x8609)
                #5  0x00007f843032d133 __clone (libc.so.6 + 0x11f133)
                
                Stack trace of thread 1437082:
                #0  0x00007f843032099f __GI___poll (libc.so.6 + 0x11299f)
                #1  0x00007f842ed4336e n/a (libglib-2.0.so.0 + 0x5236e)
                #2  0x00007f842ed434a3 g_main_context_iteration (libglib-2.0.so.0 + 0x524a3)
                #3  0x00007f8430b0fb82 _ZN20QEventDispatcherGlib13processEventsE6QFlagsIN10QEventLoop17ProcessEventsFlagEE (libQt5Core.so.5 + 0x30fb82)
                #4  0x00007f8430ab3b3b _ZN10QEventLoop4execE6QFlagsINS_17ProcessEventsFlagEE (libQt5Core.so.5 + 0x2b3b3b)
                #5  0x00007f84308cd342 _ZN7QThread4execEv (libQt5Core.so.5 + 0xcd342)
                #6  0x00007f843157af4b n/a (libQt5DBus.so.5 + 0x18f4b)
                #7  0x00007f84308ce543 _ZN14QThreadPrivate5startEPv (libQt5Core.so.5 + 0xce543)
                #8  0x00007f84322c3609 start_thread (libpthread.so.0 + 0x8609)
                #9  0x00007f843032d133 __clone (libc.so.6 + 0x11f133)
                
                Stack trace of thread 1437347:
                #0  0x00007f84322ca376 futex_wait_cancelable (libpthread.so.0 + 0xf376)
                #1  0x00007f84308d45eb _ZN21QWaitConditionPrivate4waitE14QDeadlineTimer (libQt5Core.so.5 + 0xd45eb)
                #2  0x00007f8432623394 _ZN25QSGRenderThreadEventQueue9takeEventEb (libQt5Quick.so.5 + 0x223394)
                #3  0x00007f8432623809 _ZN15QSGRenderThread3runEv (libQt5Quick.so.5 + 0x223809)
                #4  0x00007f84308ce543 _ZN14QThreadPrivate5startEPv (libQt5Core.so.5 + 0xce543)
                #5  0x00007f84322c3609 start_thread (libpthread.so.0 + 0x8609)
                #6  0x00007f843032d133 __clone (libc.so.6 + 0x11f133)
                
                Stack trace of thread 1437379:
                #0  0x00007f84322ca376 futex_wait_cancelable (libpthread.so.0 + 0xf376)
                #1  0x00007f84308d45eb _ZN21QWaitConditionPrivate4waitE14QDeadlineTimer (libQt5Core.so.5 + 0xd45eb)
                #2  0x00007f8432623394 _ZN25QSGRenderThreadEventQueue9takeEventEb (libQt5Quick.so.5 + 0x223394)
                #3  0x00007f8432623809 _ZN15QSGRenderThread3runEv (libQt5Quick.so.5 + 0x223809)
                #4  0x00007f84308ce543 _ZN14QThreadPrivate5startEPv (libQt5Core.so.5 + 0xce543)
                #5  0x00007f84322c3609 start_thread (libpthread.so.0 + 0x8609)
                #6  0x00007f843032d133 __clone (libc.so.6 + 0x11f133)
                
                Stack trace of thread 1437390:
                #0  0x00007f84322ca376 futex_wait_cancelable (libpthread.so.0 + 0xf376)
                #1  0x00007f84308d45eb _ZN21QWaitConditionPrivate4waitE14QDeadlineTimer (libQt5Core.so.5 + 0xd45eb)
                #2  0x00007f8432623394 _ZN25QSGRenderThreadEventQueue9takeEventEb (libQt5Quick.so.5 + 0x223394)
                #3  0x00007f8432623809 _ZN15QSGRenderThread3runEv (libQt5Quick.so.5 + 0x223809)
                #4  0x00007f84308ce543 _ZN14QThreadPrivate5startEPv (libQt5Core.so.5 + 0xce543)
                #5  0x00007f84322c3609 start_thread (libpthread.so.0 + 0x8609)
                #6  0x00007f843032d133 __clone (libc.so.6 + 0x11f133)
                
                Stack trace of thread 1437087:
                #0  0x00007f84322ca376 futex_wait_cancelable (libpthread.so.0 + 0xf376)
                #1  0x00007f84286c3e8b n/a (radeonsi_dri.so + 0xc3e8b)
                #2  0x00007f84286c3bdb n/a (radeonsi_dri.so + 0xc3bdb)
                #3  0x00007f84322c3609 start_thread (libpthread.so.0 + 0x8609)
                #4  0x00007f843032d133 __clone (libc.so.6 + 0x11f133)
                
                Stack trace of thread 1437092:
                #0  0x00007f84322ca376 futex_wait_cancelable (libpthread.so.0 + 0xf376)
                #1  0x00007f84286c3e8b n/a (radeonsi_dri.so + 0xc3e8b)
                #2  0x00007f84286c3bdb n/a (radeonsi_dri.so + 0xc3bdb)
                #3  0x00007f84322c3609 start_thread (libpthread.so.0 + 0x8609)
                #4  0x00007f843032d133 __clone (libc.so.6 + 0x11f133)
                
                Stack trace of thread 1437093:
                #0  0x00007f84322ca376 futex_wait_cancelable (libpthread.so.0 + 0xf376)
                #1  0x00007f84286c3e8b n/a (radeonsi_dri.so + 0xc3e8b)
                #2  0x00007f84286c3bdb n/a (radeonsi_dri.so + 0xc3bdb)
                #3  0x00007f84322c3609 start_thread (libpthread.so.0 + 0x8609)
                #4  0x00007f843032d133 __clone (libc.so.6 + 0x11f133)
                
                Stack trace of thread 1437168:
                #0  0x00007f843032099f __GI___poll (libc.so.6 + 0x11299f)
                #1  0x00007f842ed4336e n/a (libglib-2.0.so.0 + 0x5236e)
                #2  0x00007f842ed434a3 g_main_context_iteration (libglib-2.0.so.0 + 0x524a3)
                #3  0x00007f8430b0fb82 _ZN20QEventDispatcherGlib13processEventsE6QFlagsIN10QEventLoop17ProcessEventsFlagEE (libQt5Core.so.5 + 0x30fb82)
                #4  0x00007f8430ab3b3b _ZN10QEventLoop4execE6QFlagsINS_17ProcessEventsFlagEE (libQt5Core.so.5 + 0x2b3b3b)
                #5  0x00007f84308cd342 _ZN7QThread4execEv (libQt5Core.so.5 + 0xcd342)
                #6  0x00007f84308ce543 _ZN14QThreadPrivate5startEPv (libQt5Core.so.5 + 0xce543)
                #7  0x00007f84322c3609 start_thread (libpthread.so.0 + 0x8609)
                #8  0x00007f843032d133 __clone (libc.so.6 + 0x11f133)
                
                Stack trace of thread 1437118:
                #0  0x00007f843032099f __GI___poll (libc.so.6 + 0x11299f)
                #1  0x00007f842ed4336e n/a (libglib-2.0.so.0 + 0x5236e)
                #2  0x00007f842ed434a3 g_main_context_iteration (libglib-2.0.so.0 + 0x524a3)
                #3  0x00007f8430b0fb82 _ZN20QEventDispatcherGlib13processEventsE6QFlagsIN10QEventLoop17ProcessEventsFlagEE (libQt5Core.so.5 + 0x30fb82)
                #4  0x00007f8430ab3b3b _ZN10QEventLoop4execE6QFlagsINS_17ProcessEventsFlagEE (libQt5Core.so.5 + 0x2b3b3b)
                #5  0x00007f84308cd342 _ZN7QThread4execEv (libQt5Core.so.5 + 0xcd342)
                #6  0x00007f843255d67a _ZN18QQuickPixmapReader3runEv (libQt5Quick.so.5 + 0x15d67a)
                #7  0x00007f84308ce543 _ZN14QThreadPrivate5startEPv (libQt5Core.so.5 + 0xce543)
                #8  0x00007f84322c3609 start_thread (libpthread.so.0 + 0x8609)
                #9  0x00007f843032d133 __clone (libc.so.6 + 0x11f133)
                
                Stack trace of thread 1437104:
                #0  0x00007f843032099f __GI___poll (libc.so.6 + 0x11299f)
                #1  0x00007f842ed4336e n/a (libglib-2.0.so.0 + 0x5236e)
                #2  0x00007f842ed434a3 g_main_context_iteration (libglib-2.0.so.0 + 0x524a3)
                #3  0x00007f8430b0fb82 _ZN20QEventDispatcherGlib13processEventsE6QFlagsIN10QEventLoop17ProcessEventsFlagEE (libQt5Core.so.5 + 0x30fb82)
                #4  0x00007f8430ab3b3b _ZN10QEventLoop4execE6QFlagsINS_17ProcessEventsFlagEE (libQt5Core.so.5 + 0x2b3b3b)
                #5  0x00007f84308cd342 _ZN7QThread4execEv (libQt5Core.so.5 + 0xcd342)
                #6  0x00007f8432160919 _ZN17QQmlThreadPrivate3runEv (libQt5Qml.so.5 + 0x360919)
                #7  0x00007f84308ce543 _ZN14QThreadPrivate5startEPv (libQt5Core.so.5 + 0xce543)
                #8  0x00007f84322c3609 start_thread (libpthread.so.0 + 0x8609)
                #9  0x00007f843032d133 __clone (libc.so.6 + 0x11f133)
                
                Stack trace of thread 1437094:
                #0  0x00007f84322ca376 futex_wait_cancelable (libpthread.so.0 + 0xf376)
                #1  0x00007f84286c3e8b n/a (radeonsi_dri.so + 0xc3e8b)
                #2  0x00007f84286c3bdb n/a (radeonsi_dri.so + 0xc3bdb)
                #3  0x00007f84322c3609 start_thread (libpthread.so.0 + 0x8609)
                #4  0x00007f843032d133 __clone (libc.so.6 + 0x11f133)
                
                Stack trace of thread 1437378:
                #0  0x00007f84322ca376 futex_wait_cancelable (libpthread.so.0 + 0xf376)
                #1  0x00007f84286c3e8b n/a (radeonsi_dri.so + 0xc3e8b)
                #2  0x00007f84286c3bdb n/a (radeonsi_dri.so + 0xc3bdb)
                #3  0x00007f84322c3609 start_thread (libpthread.so.0 + 0x8609)
                #4  0x00007f843032d133 __clone (libc.so.6 + 0x11f133)
                
                Stack trace of thread 1437142:
                #0  0x00007f84322ca7d1 futex_abstimed_wait_cancelable (libpthread.so.0 + 0xf7d1)
                #1  0x00007f84308d4578 _ZN21QWaitConditionPrivate13wait_relativeE14QDeadlineTimer (libQt5Core.so.5 + 0xd4578)
                #2  0x00007f84308d1a91 _ZN17QThreadPoolThread3runEv (libQt5Core.so.5 + 0xd1a91)
                #3  0x00007f84308ce543 _ZN14QThreadPrivate5startEPv (libQt5Core.so.5 + 0xce543)
                #4  0x00007f84322c3609 start_thread (libpthread.so.0 + 0x8609)
                #5  0x00007f843032d133 __clone (libc.so.6 + 0x11f133)
                
                Stack trace of thread 1437083:
                #0  0x00007f843032099f __GI___poll (libc.so.6 + 0x11299f)
                #1  0x00007f8433217c1a n/a (libxcb.so.1 + 0xbc1a)
                #2  0x00007f843321990a xcb_wait_for_event (libxcb.so.1 + 0xd90a)
                #3  0x00007f842c0dbe18 _ZN14QXcbEventQueue3runEv (libQt5XcbQpa.so.5 + 0x78e18)
                #4  0x00007f84308ce543 _ZN14QThreadPrivate5startEPv (libQt5Core.so.5 + 0xce543)
                #5  0x00007f84322c3609 start_thread (libpthread.so.0 + 0x8609)
                #6  0x00007f843032d133 __clone (libc.so.6 + 0x11f133)
                
                Stack trace of thread 1437144:
                #0  0x00007f84322ca7d1 futex_abstimed_wait_cancelable (libpthread.so.0 + 0xf7d1)
                #1  0x00007f84308d4578 _ZN21QWaitConditionPrivate13wait_relativeE14QDeadlineTimer (libQt5Core.so.5 + 0xd4578)
                #2  0x00007f84308d1a91 _ZN17QThreadPoolThread3runEv (libQt5Core.so.5 + 0xd1a91)
                #3  0x00007f84308ce543 _ZN14QThreadPrivate5startEPv (libQt5Core.so.5 + 0xce543)
                #4  0x00007f84322c3609 start_thread (libpthread.so.0 + 0x8609)
                #5  0x00007f843032d133 __clone (libc.so.6 + 0x11f133)
                
                Stack trace of thread 1437145:
                #0  0x00007f84322ca7d1 futex_abstimed_wait_cancelable (libpthread.so.0 + 0xf7d1)
                #1  0x00007f84308d4578 _ZN21QWaitConditionPrivate13wait_relativeE14QDeadlineTimer (libQt5Core.so.5 + 0xd4578)
                #2  0x00007f84308d1a91 _ZN17QThreadPoolThread3runEv (libQt5Core.so.5 + 0xd1a91)
                #3  0x00007f84308ce543 _ZN14QThreadPrivate5startEPv (libQt5Core.so.5 + 0xce543)
                #4  0x00007f84322c3609 start_thread (libpthread.so.0 + 0x8609)
                #5  0x00007f843032d133 __clone (libc.so.6 + 0x11f133)
                
                Stack trace of thread 1437146:
                #0  0x00007f84322ca7d1 futex_abstimed_wait_cancelable (libpthread.so.0 + 0xf7d1)
                #1  0x00007f84308d4578 _ZN21QWaitConditionPrivate13wait_relativeE14QDeadlineTimer (libQt5Core.so.5 + 0xd4578)
                #2  0x00007f84308d1a91 _ZN17QThreadPoolThread3runEv (libQt5Core.so.5 + 0xd1a91)
                #3  0x00007f84308ce543 _ZN14QThreadPrivate5startEPv (libQt5Core.so.5 + 0xce543)
                #4  0x00007f84322c3609 start_thread (libpthread.so.0 + 0x8609)
                #5  0x00007f843032d133 __clone (libc.so.6 + 0x11f133)
                
                Stack trace of thread 1437344:
                #0  0x00007f84322ca376 futex_wait_cancelable (libpthread.so.0 + 0xf376)
                #1  0x00007f84308d45eb _ZN21QWaitConditionPrivate4waitE14QDeadlineTimer (libQt5Core.so.5 + 0xd45eb)
                #2  0x00007f8432623394 _ZN25QSGRenderThreadEventQueue9takeEventEb (libQt5Quick.so.5 + 0x223394)
                #3  0x00007f8432623809 _ZN15QSGRenderThread3runEv (libQt5Quick.so.5 + 0x223809)
                #4  0x00007f84308ce543 _ZN14QThreadPrivate5startEPv (libQt5Core.so.5 + 0xce543)
                #5  0x00007f84322c3609 start_thread (libpthread.so.0 + 0x8609)
                #6  0x00007f843032d133 __clone (libc.so.6 + 0x11f133)
                
                Stack trace of thread 1437147:
                #0  0x00007f84322ca7d1 futex_abstimed_wait_cancelable (libpthread.so.0 + 0xf7d1)
                #1  0x00007f84308d4578 _ZN21QWaitConditionPrivate13wait_relativeE14QDeadlineTimer (libQt5Core.so.5 + 0xd4578)
                #2  0x00007f84308d1a91 _ZN17QThreadPoolThread3runEv (libQt5Core.so.5 + 0xd1a91)
                #3  0x00007f84308ce543 _ZN14QThreadPrivate5startEPv (libQt5Core.so.5 + 0xce543)
                #4  0x00007f84322c3609 start_thread (libpthread.so.0 + 0x8609)
                #5  0x00007f843032d133 __clone (libc.so.6 + 0x11f133)
                
                Stack trace of thread 1437356:
                #0  0x00007f84322ca376 futex_wait_cancelable (libpthread.so.0 + 0xf376)
                #1  0x00007f84286c3e8b n/a (radeonsi_dri.so + 0xc3e8b)
                #2  0x00007f84286c3bdb n/a (radeonsi_dri.so + 0xc3bdb)
                #3  0x00007f84322c3609 start_thread (libpthread.so.0 + 0x8609)
                #4  0x00007f843032d133 __clone (libc.so.6 + 0x11f133)
                
                Stack trace of thread 1437280:
                #0  0x00007f843032099f __GI___poll (libc.so.6 + 0x11299f)
                #1  0x00007f842ed4336e n/a (libglib-2.0.so.0 + 0x5236e)
                #2  0x00007f842ed434a3 g_main_context_iteration (libglib-2.0.so.0 + 0x524a3)
                #3  0x00007f8430b0fb82 _ZN20QEventDispatcherGlib13processEventsE6QFlagsIN10QEventLoop17ProcessEventsFlagEE (libQt5Core.so.5 + 0x30fb82)
                #4  0x00007f8430ab3b3b _ZN10QEventLoop4execE6QFlagsINS_17ProcessEventsFlagEE (libQt5Core.so.5 + 0x2b3b3b)
                #5  0x00007f84308cd342 _ZN7QThread4execEv (libQt5Core.so.5 + 0xcd342)
                #6  0x00007f839cd5c0bc _ZN15KCupsConnection3runEv (libkcupslib.so + 0x230bc)
                #7  0x00007f84308ce543 _ZN14QThreadPrivate5startEPv (libQt5Core.so.5 + 0xce543)
                #8  0x00007f84322c3609 start_thread (libpthread.so.0 + 0x8609)
                #9  0x00007f843032d133 __clone (libc.so.6 + 0x11f133)
                
                Stack trace of thread 1437345:
                #0  0x00007f84322ca376 futex_wait_cancelable (libpthread.so.0 + 0xf376)
                #1  0x00007f84286c3e8b n/a (radeonsi_dri.so + 0xc3e8b)
                #2  0x00007f84286c3bdb n/a (radeonsi_dri.so + 0xc3bdb)
                #3  0x00007f84322c3609 start_thread (libpthread.so.0 + 0x8609)
                #4  0x00007f843032d133 __clone (libc.so.6 + 0x11f133)
                
                Stack trace of thread 1437389:
                #0  0x00007f84322ca376 futex_wait_cancelable (libpthread.so.0 + 0xf376)
                #1  0x00007f84286c3e8b n/a (radeonsi_dri.so + 0xc3e8b)
                #2  0x00007f84286c3bdb n/a (radeonsi_dri.so + 0xc3bdb)
                #3  0x00007f84322c3609 start_thread (libpthread.so.0 + 0x8609)
                #4  0x00007f843032d133 __clone (libc.so.6 + 0x11f133)
                
                Stack trace of thread 1437120:
                #0  0x00007f84322ca376 futex_wait_cancelable (libpthread.so.0 + 0xf376)
                #1  0x00007f84286c3e8b n/a (radeonsi_dri.so + 0xc3e8b)
                #2  0x00007f84286c3bdb n/a (radeonsi_dri.so + 0xc3bdb)
                #3  0x00007f84322c3609 start_thread (libpthread.so.0 + 0x8609)
                #4  0x00007f843032d133 __clone (libc.so.6 + 0x11f133)
                
                Stack trace of thread 1437141:
                #0  0x00007f84322ca7d1 futex_abstimed_wait_cancelable (libpthread.so.0 + 0xf7d1)
                #1  0x00007f84308d4578 _ZN21QWaitConditionPrivate13wait_relativeE14QDeadlineTimer (libQt5Core.so.5 + 0xd4578)
                #2  0x00007f84308d1a91 _ZN17QThreadPoolThread3runEv (libQt5Core.so.5 + 0xd1a91)
                #3  0x00007f84308ce543 _ZN14QThreadPrivate5startEPv (libQt5Core.so.5 + 0xce543)
                #4  0x00007f84322c3609 start_thread (libpthread.so.0 + 0x8609)
                #5  0x00007f843032d133 __clone (libc.so.6 + 0x11f133)
                
                Stack trace of thread 1437380:
                #0  0x00007f843032099f __GI___poll (libc.so.6 + 0x11299f)
                #1  0x00007f842ed4336e n/a (libglib-2.0.so.0 + 0x5236e)
                #2  0x00007f842ed434a3 g_main_context_iteration (libglib-2.0.so.0 + 0x524a3)
                #3  0x00007f8430b0fb82 _ZN20QEventDispatcherGlib13processEventsE6QFlagsIN10QEventLoop17ProcessEventsFlagEE (libQt5Core.so.5 + 0x30fb82)
                #4  0x00007f8430ab3b3b _ZN10QEventLoop4execE6QFlagsINS_17ProcessEventsFlagEE (libQt5Core.so.5 + 0x2b3b3b)
                #5  0x00007f84308cd342 _ZN7QThread4execEv (libQt5Core.so.5 + 0xcd342)
                #6  0x00007f84308ce543 _ZN14QThreadPrivate5startEPv (libQt5Core.so.5 + 0xce543)
                #7  0x00007f84322c3609 start_thread (libpthread.so.0 + 0x8609)
                #8  0x00007f843032d133 __clone (libc.so.6 + 0x11f133)
                
                Stack trace of thread 1437357:
                #0  0x00007f84322ca376 futex_wait_cancelable (libpthread.so.0 + 0xf376)
                #1  0x00007f84308d45eb _ZN21QWaitConditionPrivate4waitE14QDeadlineTimer (libQt5Core.so.5 + 0xd45eb)
                #2  0x00007f8432623394 _ZN25QSGRenderThreadEventQueue9takeEventEb (libQt5Quick.so.5 + 0x223394)
                #3  0x00007f8432623809 _ZN15QSGRenderThread3runEv (libQt5Quick.so.5 + 0x223809)
                #4  0x00007f84308ce543 _ZN14QThreadPrivate5startEPv (libQt5Core.so.5 + 0xce543)
                #5  0x00007f84322c3609 start_thread (libpthread.so.0 + 0x8609)
                #6  0x00007f843032d133 __clone (libc.so.6 + 0x11f133)
                
                Stack trace of thread 1437095:
                #0  0x00007f84322ca376 futex_wait_cancelable (libpthread.so.0 + 0xf376)
                #1  0x00007f84286c3e8b n/a (radeonsi_dri.so + 0xc3e8b)
                #2  0x00007f84286c3bdb n/a (radeonsi_dri.so + 0xc3bdb)
                #3  0x00007f84322c3609 start_thread (libpthread.so.0 + 0x8609)
                #4  0x00007f843032d133 __clone (libc.so.6 + 0x11f133)
                
                Stack trace of thread 1437343:
                #0  0x00007f84322ca376 futex_wait_cancelable (libpthread.so.0 + 0xf376)
                #1  0x00007f84286c3e8b n/a (radeonsi_dri.so + 0xc3e8b)
                #2  0x00007f84286c3bdb n/a (radeonsi_dri.so + 0xc3bdb)
                #3  0x00007f84322c3609 start_thread (libpthread.so.0 + 0x8609)
                #4  0x00007f843032d133 __clone (libc.so.6 + 0x11f133)
                
                Stack trace of thread 1437121:
                #0  0x00007f84322ca376 futex_wait_cancelable (libpthread.so.0 + 0xf376)
                #1  0x00007f84308d45eb _ZN21QWaitConditionPrivate4waitE14QDeadlineTimer (libQt5Core.so.5 + 0xd45eb)
                #2  0x00007f8432623394 _ZN25QSGRenderThreadEventQueue9takeEventEb (libQt5Quick.so.5 + 0x223394)
                #3  0x00007f8432623809 _ZN15QSGRenderThread3runEv (libQt5Quick.so.5 + 0x223809)
                #4  0x00007f84308ce543 _ZN14QThreadPrivate5startEPv (libQt5Core.so.5 + 0xce543)
                #5  0x00007f84322c3609 start_thread (libpthread.so.0 + 0x8609)
                #6  0x00007f843032d133 __clone (libc.so.6 + 0x11f133)
                
                Stack trace of thread 1437097:
                #0  0x00007f84322ca376 futex_wait_cancelable (libpthread.so.0 + 0xf376)
                #1  0x00007f84286c3e8b n/a (radeonsi_dri.so + 0xc3e8b)
                #2  0x00007f84286c3bdb n/a (radeonsi_dri.so + 0xc3bdb)
                #3  0x00007f84322c3609 start_thread (libpthread.so.0 + 0x8609)
                #4  0x00007f843032d133 __clone (libc.so.6 + 0x11f133)
                
                Stack trace of thread 1437086:
                #0  0x00007f84322ca376 futex_wait_cancelable (libpthread.so.0 + 0xf376)
                #1  0x00007f84286c3e8b n/a (radeonsi_dri.so + 0xc3e8b)
                #2  0x00007f84286c3bdb n/a (radeonsi_dri.so + 0xc3bdb)
                #3  0x00007f84322c3609 start_thread (libpthread.so.0 + 0x8609)
                #4  0x00007f843032d133 __clone (libc.so.6 + 0x11f133)

GNU gdb (Ubuntu 10.2-0ubuntu1~20.04~1) 10.2
Copyright (C) 2021 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:
<https://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"...
Reading symbols from /usr/bin/plasmashell...
(No debugging symbols found in /usr/bin/plasmashell)

warning: Can't open file /memfd:pulseaudio (deleted) during file-backed mapping note processing

warning: Can't open file /memfd:unknown-usage:QtQml (deleted) during file-backed mapping note processing

warning: Can't open file /memfd:JSGCHeap:QtQml (deleted) during file-backed mapping note processing

warning: Can't open file /memfd:JITCode:QtQml (deleted) during file-backed mapping note processing

warning: Can't open file /home/riccardo/.cache/plasmashell/qmlcache/c1600cc797c41f278479c5812c87627ad5efdfe4.qmlc (deleted) during file-backed mapping note processing

warning: Can't open file /home/riccardo/.cache/plasmashell/qmlcache/1b5209199f08f45647dca2dcf400e9be889314d2.qmlc (deleted) during file-backed mapping note processing

warning: Can't open file /home/riccardo/.cache/plasmashell/qmlcache/33c917e773abe4bc3a0103a6068c9216dcb36d95.qmlc (deleted) during file-backed mapping note processing

warning: Can't open file /home/riccardo/.cache/plasmashell/qmlcache/d99054e44f60991aab9ed908f1e542f4c0cd78b9.qmlc (deleted) during file-backed mapping note processing

warning: Can't open file /home/riccardo/.cache/plasmashell/qmlcache/b142c0f82ac26290f689323dba70cf4f115584f1.qmlc (deleted) during file-backed mapping note processing

warning: Can't open file /memfd:xshmfence (deleted) during file-backed mapping note processing

warning: Can't open file /memfd:JSVMStack:QtQml (deleted) during file-backed mapping note processing

warning: Can't open file /home/riccardo/.cache/plasmashell/qmlcache/5f612594f2dbf235ceb0690f5ba4a2d73e811317.qmlc (deleted) during file-backed mapping note processing
[New LWP 1437070]
[New LWP 1437091]
[New LWP 1437090]
[New LWP 1437084]
[New LWP 1437085]
[New LWP 1437089]
[New LWP 1437088]
[New LWP 1437140]
[New LWP 1437316]
[New LWP 1437317]
[New LWP 1437143]
[New LWP 1437082]
[New LWP 1437347]
[New LWP 1437379]
[New LWP 1437390]
[New LWP 1437087]
[New LWP 1437092]
[New LWP 1437093]
[New LWP 1437168]
[New LWP 1437118]
[New LWP 1437104]
[New LWP 1437094]
[New LWP 1437378]
[New LWP 1437142]
[New LWP 1437083]
[New LWP 1437144]
[New LWP 1437145]
[New LWP 1437146]
[New LWP 1437344]
[New LWP 1437147]
[New LWP 1437356]
[New LWP 1437280]
[New LWP 1437345]
[New LWP 1437389]
[New LWP 1437120]
[New LWP 1437141]
[New LWP 1437380]
[New LWP 1437357]
[New LWP 1437095]
[New LWP 1437343]
[New LWP 1437121]
[New LWP 1437097]
[New LWP 1437086]
[Thread debugging using libthread_db enabled]
Using host libthread_db library "/lib/x86_64-linux-gnu/libthread_db.so.1".
--Type <RET> for more, q to quit, c to continue without paging--
Core was generated by `/usr/bin/plasmashell'.
Program terminated with signal SIGSEGV, Segmentation fault.
#0  __GI_raise (sig=<optimised out>) at ../sysdeps/unix/sysv/linux/raise.c:50
50      ../sysdeps/unix/sysv/linux/raise.c: No such file or directory.
[Current thread is 1 (Thread 0x7f842c7de9c0 (LWP 1437070))]
(gdb) bt
#0  __GI_raise (sig=<optimised out>) at ../sysdeps/unix/sysv/linux/raise.c:50
#1  0x00007f8432bc1ff5 in KCrash::defaultCrashHandler(int) () at /usr/lib/x86_64-linux-gnu/libKF5Crash.so.5
#2  0x00007f8430251090 in <signal handler called> () at /lib/x86_64-linux-gnu/libc.so.6
#3  0x00007f8432096e73 in qGetPtrHelper<QScopedPointer<QObjectData, QScopedPointerDeleter<QObjectData> > >(QScopedPointer<QObjectData, QScopedPointerDeleter<QObjectData> >&) (ptr=...)
    at /usr/include/x86_64-linux-gnu/qt5/QtCore/qglobal.h:1143
#4  QQmlEngine::d_func() (this=0x0) at qml/qqmlengine.h:172
#5  QQmlEnginePrivate::get(QQmlEngine*) (e=0x0) at qml/qqmlengine_p.h:424
#6  QtQml::qmlExecuteDeferred(QObject*) (object=object@entry=0x55fc87219b50) at qml/qqmlengine.cpp:1582
#7  0x00007f843255046e in QQuickTransition::prepare(QList<QQuickStateAction>&, QList<QQmlProperty>&, QQuickTransitionManager*, QObject*)
    (this=this@entry=0x55fc87219b50, actions=..., after=..., manager=manager@entry=0x55fc86bbe9b0, defaultTarget=defaultTarget@entry=0x55fc872148e0) at util/qquicktransition.cpp:259
#8  0x00007f843254603f in QQuickTransitionManager::transition(QList<QQuickStateAction> const&, QQuickTransition*, QObject*)
    (this=0x55fc86bbe9b0, list=<optimised out>, transition=0x55fc87219b50, defaultTarget=<optimised out>) at util/qquicktransitionmanager.cpp:207
#9  0x00007f8430ae2c25 in QObject::event(QEvent*) (this=0x55fc872148e0, e=0x7ffff4bb9d80) at kernel/qobject.cpp:1369
#10 0x00007f843176de43 in QApplicationPrivate::notify_helper(QObject*, QEvent*) (this=this@entry=0x55fc83e70100, receiver=receiver@entry=0x55fc872148e0, e=e@entry=0x7ffff4bb9d80) at kernel/qapplication.cpp:3637
#11 0x00007f8431776c58 in QApplication::notify(QObject*, QEvent*) (this=0x7ffff4bba100, receiver=0x55fc872148e0, e=0x7ffff4bb9d80) at kernel/qapplication.cpp:3161
#12 0x00007f8430ab503a in QCoreApplication::notifyInternal2(QObject*, QEvent*) (receiver=0x55fc872148e0, event=0x7ffff4bb9d80) at kernel/qcoreapplication.cpp:1064
#13 0x00007f8430b0eed0 in QTimerInfoList::activateTimers() (this=0x55fc83f30160) at kernel/qtimerinfo_unix.cpp:643
#14 0x00007f8430b0f804 in timerSourceDispatch (source=<optimised out>) at kernel/qeventdispatcher_glib.cpp:183
#15 idleTimerSourceDispatch(GSource*, GSourceFunc, gpointer) (source=<optimised out>) at kernel/qeventdispatcher_glib.cpp:230
#16 0x00007f842ed4317d in g_main_context_dispatch () at /usr/lib/x86_64-linux-gnu/libglib-2.0.so.0
#17 0x00007f842ed43400 in  () at /usr/lib/x86_64-linux-gnu/libglib-2.0.so.0
#18 0x00007f842ed434a3 in g_main_context_iteration () at /usr/lib/x86_64-linux-gnu/libglib-2.0.so.0
#19 0x00007f8430b0fb82 in QEventDispatcherGlib::processEvents(QFlags<QEventLoop::ProcessEventsFlag>) (this=0x55fc83f35ac0, flags=...) at kernel/qeventdispatcher_glib.cpp:423
#20 0x00007f8430ab3b3b in QEventLoop::exec(QFlags<QEventLoop::ProcessEventsFlag>) (this=this@entry=0x7ffff4bb9fc0, flags=..., flags@entry=...) at ../../include/QtCore/../../src/corelib/global/qflags.h:69
#21 0x00007f8430abbce4 in QCoreApplication::exec() () at ../../include/QtCore/../../src/corelib/global/qflags.h:121
#22 0x000055fc82af37ec in  ()
--Type <RET> for more, q to quit, c to continue without paging--
#23 0x00007f8430232083 in __libc_start_main (main=0x55fc82af28d0, argc=1, argv=0x7ffff4bba278, init=<optimised out>, fini=<optimised out>, rtld_fini=<optimised out>, stack_end=0x7ffff4bba268)
    at ../csu/libc-start.c:308
#24 0x000055fc82af391e in  ()

Thanks. Unfortunately no KDE code looks to be implicated in the backtrace. I'm not sure how to proceed.

Should be worked around by https://invent.kde.org/plasma/plasma-workspace/-/merge_requests/2326

Please reopen if you still encounter the same bug

*** Bug 462715 has been marked as a duplicate of this bug. ***

*** Bug 463956 has been marked as a duplicate of this bug. ***

*** Bug 461679 has been marked as a duplicate of this bug. ***

Created attachment 155758 [details]
Backtrace

I've just had a Plasmashell crash with Plasma 5.26.5. Which version was the fix included in?

Created attachment 159735 [details]
New crash information added by DrKonqi

plasmashell (5.27.5) using Qt 5.15.9

without my doing anything , the "sticky note" got added to my desktop, not one but two. when i removed them , they complied and there were two pormpt notification about the removal. when i crossed ist , nothing happened but when i crossed the 2nd and last one , the plasma crashed and here i am.

ist time this occured , i ignored coz my system is decade old . Dell E6420 . but when the 2nd time same happened , i complain!!

-- Backtrace (Reduced):
#5  0x00007f3922c9399d in QtQml::qmlExecuteDeferred(QObject*) () from /lib64/libQt5Qml.so.5
#6  0x00007f3923178dc9 in QQuickTransition::prepare(QList<QQuickStateAction>&, QList<QQmlProperty>&, QQuickTransitionManager*, QObject*) () from /lib64/libQt5Quick.so.5
#7  0x00007f392316e2e7 in QQuickTransitionManager::transition(QList<QQuickStateAction> const&, QQuickTransition*, QObject*) () from /lib64/libQt5Quick.so.5
#8  0x00007f3921718b5b in QObject::event(QEvent*) () from /lib64/libQt5Core.so.5
#9  0x00007f39223a51ae in QApplicationPrivate::notify_helper(QObject*, QEvent*) () from /lib64/libQt5Widgets.so.5

*** This bug has been marked as a duplicate of bug 468180 ***