*** Bug 422420 has been marked as a duplicate of this bug. ***

Created attachment 131758 [details]
New crash information added by DrKonqi

plasmashell (5.19.90) using Qt 5.15.0

- What I was doing when the application crashed:

As soon as I selected KDE Neon from GRUB, I closed my laptop, and right after login, this error popped up.

-- Backtrace (Reduced):
#4  0x00007f789bacd866 in QScreen::name (this=0x5589acc44030) at kernel/qscreen.cpp:171
#5  0x00005589ac4b6da4 in ShellCorona::addOutput (this=this@entry=0x5589acc88ec0, screen=<optimized out>, screen@entry=0x5589acc44030) at ./shell/shellcorona.cpp:1289
#6  0x00005589ac4c15e3 in ShellCorona::load (this=0x5589acc88ec0) at ./shell/shellcorona.cpp:731
#7  0x00007f789b6ad5ae in QtPrivate::QSlotObjectBase::call (a=0x7ffcfd5db8e0, r=0x5589acc88ec0, this=0x5589ace68640) at ../../include/QtCore/../../src/corelib/kernel/qobjectdefs_impl.h:398
#8  doActivate<false> (sender=0x5589accc89a0, signal_index=4, argv=0x7ffcfd5db8e0) at kernel/qobject.cpp:3886

Duplicate of 419741?

*** Bug 426630 has been marked as a duplicate of this bug. ***

*** Bug 431401 has been marked as a duplicate of this bug. ***

*** Bug 418602 has been marked as a duplicate of this bug. ***

*** Bug 433303 has been marked as a duplicate of this bug. ***

*** Bug 390092 has been marked as a duplicate of this bug. ***

*** Bug 390171 has been marked as a duplicate of this bug. ***

*** Bug 391065 has been marked as a duplicate of this bug. ***

*** Bug 412307 has been marked as a duplicate of this bug. ***

Tones of dupes; raising priority.

*** Bug 433366 has been marked as a duplicate of this bug. ***

*** Bug 434597 has been marked as a duplicate of this bug. ***

*** Bug 436901 has been marked as a duplicate of this bug. ***

It still doesn't make any sense.

We're iterating through 

```
    const auto screens = qGuiApp->screens();
    for (QScreen *screen : screens) {
         ... screen->name() 
 

and yet end up with screen being dangling.


There's only two ways this could happen.

1) The QPA is feeding us garbage
2) someone is starting a nested event loop somewhere whilst we're in "addOutput" and this is removing a screen, whilst we iterate over the copy of the list


I checked for the latter, but found nothing. Potentially that's applet dependent, it only takes one to be doing something wrong. 

This needs investigation from someone who can reproduce it reliably before we can do anything. 

If someone can reproduce locally and can install debug symbols let me know and I'll suggest some gdb commands.

Created attachment 138356 [details]
attachment-1067-0.html

Hello David

Thanks for replying and looking into this.

Issue can be repeated.
There is also another issue happening.
If I press fn + f8 tp switch external screen off that works ok.
Then if I go to switch back to external screen computer freezes and I
cannot recover it. Mouse pointer is invisible.
These problems only happen in wayland.

I don't know about programming but I will try to install debug symbols
I think a possible way to tackle this would be if I use another computer to
communicate with
 a programmer and they could explain process in real time. That is just a
thought.

Thanks

Philip

On Wed, 12 May 2021 at 00:21, David Edmundson <bugzilla_noreply@kde.org>
wrote:

> https://bugs.kde.org/show_bug.cgi?id=421700
>
> David Edmundson <kde@davidedmundson.co.uk> changed:
>
>            What    |Removed                     |Added
>
> ----------------------------------------------------------------------------
>                  CC|                            |kde@davidedmundson.co.uk
>
> --- Comment #16 from David Edmundson <kde@davidedmundson.co.uk> ---
> It still doesn't make any sense.
>
> We're iterating through
>
> ```
>     const auto screens = qGuiApp->screens();
>     for (QScreen *screen : screens) {
>          ... screen->name()
>
>
> and yet end up with screen being dangling.
>
>
> There's only two ways this could happen.
>
> 1) The QPA is feeding us garbage
> 2) someone is starting a nested event loop somewhere whilst we're in
> "addOutput" and this is removing a screen, whilst we iterate over the copy
> of
> the list
>
>
> I checked for the latter, but found nothing. Potentially that's applet
> dependent, it only takes one to be doing something wrong.
>
> This needs investigation from someone who can reproduce it reliably before
> we
> can do anything.
>
> If someone can reproduce locally and can install debug symbols let me know
> and
> I'll suggest some gdb commands.
>
> --
> You are receiving this mail because:
> You are on the CC list for the bug.

>That is just a thought.

An excellent thought. If someone can do this reliably please find me on IRC and ping me (d_ed on Freenode)

Created attachment 138384 [details]
attachment-2506-0.html

Hi David, I have set up IRC, Using Quassel. I am  new to IRC. I was trying
to find d_ed?

On Wed, 12 May 2021 at 10:42, David Edmundson <bugzilla_noreply@kde.org>
wrote:

> https://bugs.kde.org/show_bug.cgi?id=421700
>
> --- Comment #18 from David Edmundson <kde@davidedmundson.co.uk> ---
> >That is just a thought.
>
> An excellent thought. If someone can do this reliably please find me on
> IRC and
> ping me (d_ed on Freenode)
>
> --
> You are receiving this mail because:
> You are on the CC list for the bug.

*** Bug 437530 has been marked as a duplicate of this bug. ***

*** Bug 438330 has been marked as a duplicate of this bug. ***

Number of duplicates increasing; raising priority.

*** Bug 438499 has been marked as a duplicate of this bug. ***

*** Bug 438588 has been marked as a duplicate of this bug. ***

*** Bug 439086 has been marked as a duplicate of this bug. ***

Created attachment 139830 [details]
Full stacktrace with debug symbols

Operating System: openSUSE Tumbleweed 20210701
KDE Plasma Version: 5.22.2
KDE Frameworks Version: 5.83.0
Qt Version: 5.15.2
Kernel Version: 5.12.13-1-default (64-bit)
Graphics Platform: Wayland
Graphics Processor: Radeon RX 580 Series

Happens when I attach/turn on a second monitor via HDMI on Wayland.

*** Bug 439500 has been marked as a duplicate of this bug. ***

Same crash when Wayland starts with with my external DisplayLink Plugable USB-VGA-165 plugged in. I have to fall-back to Xorg in the meantime.

Operating System: openSUSE Tumbleweed 20210711
KDE Plasma Version: 5.22.3
KDE Frameworks Version: 5.83.0
Qt Version: 5.15.2
Kernel Version: 5.12.13-1-default (64-bit)
Graphics Platform: Wayland
Processors: 12 × Intel® Core™ i7-8750H CPU @ 2.20GHz
Memory: 15.3 Gio of RAM
Graphics Processor: Mesa DRI Intel® UHD Graphics 630 AND DisplayLink UDL-165

I have the same backtrace as postix.

And I confirm that the crash is due to a dangling pointer. The QScreen seems to be deleted, since its d-ptr value is garbage (0x2 in my case.)

(gdb) thread 6
[Switching to thread 6 (Thread 0x7f2bae0c8880 (LWP 4871))]
#0  0x00007f2bb04c959f in __GI___poll (fds=0x7ffde21c9c60, nfds=1, timeout=1000) at ../sysdeps/unix/sysv/linux/poll.c:29
29        return SYSCALL_CANCEL (poll, fds, nfds, timeout);
(gdb) up 4
#4  0x00007f2bb0f17a40 in QScreen::name (this=0x55b15d5a00f0) at kernel/qscreen.cpp:195
195         return d->platformScreen->name();
(gdb) print this
$1 = (const QScreen * const) 0x55b15d5a00f0
(gdb) print this->d_ptr.d
$2 = (QObjectData *) 0x2

*** Bug 440104 has been marked as a duplicate of this bug. ***

*** Bug 440083 has been marked as a duplicate of this bug. ***

*** Bug 440224 has been marked as a duplicate of this bug. ***

*** Bug 419742 has been marked as a duplicate of this bug. ***

*** Bug 440771 has been marked as a duplicate of this bug. ***

Created attachment 140792 [details]
New crash information added by DrKonqi

plasmashell (5.22.4) using Qt 5.15.3

- What I was doing when the application crashed:

I was typing in Idea with VLC playing ogg files.

-- Backtrace (Reduced):
#4  0x00007fbbf6ae7c76 in QScreen::name() const () from /usr/lib/x86_64-linux-gnu/libQt5Gui.so.5
#5  0x0000559268caeb1a in ShellCorona::load (this=0x559268d9b000) at ./shell/shellcorona.cpp:700
[...]
#7  0x00007fbbf8a34da5 in KActivities::Consumer::serviceStatusChanged (this=<optimized out>, _t1=<optimized out>) at ./obj-x86_64-linux-gnu/src/lib/KF5Activities_autogen/EWIEGA46WW/moc_consumer.cpp:253
[...]
#9  0x00007fbbf8a34d45 in KActivities::ActivitiesCache::serviceStatusChanged (this=this@entry=0x559268f1fe40, _t1=<optimized out>, _t1@entry=KActivities::Consumer::Running) at ./obj-x86_64-linux-gnu/src/lib/KF5Activities_autogen/EWIEGA46WW/moc_activitiescache_p.cpp:412
#10 0x00007fbbf8a4e046 in KActivities::ActivitiesCache::setAllActivities (this=this@entry=0x559268f1fe40, _activities=...) at ./src/lib/activitiescache_p.cpp:270

Created attachment 140803 [details]
New crash information added by DrKonqi

plasmashell (5.22.4) using Qt 5.15.3

- What I was doing when the application crashed:

I was typing into Intelij Idea while listening to music played by VLC. Then the whole wayland session reset

-- Backtrace (Reduced):
#4  0x00007fa75d4b9c76 in QScreen::name() const () from /usr/lib/x86_64-linux-gnu/libQt5Gui.so.5
#5  0x000055df17f8cb1a in ShellCorona::load (this=0x55df18f8dc00) at ./shell/shellcorona.cpp:700
[...]
#7  0x00007fa75f411da5 in KActivities::Consumer::serviceStatusChanged (this=<optimized out>, _t1=<optimized out>) at ./obj-x86_64-linux-gnu/src/lib/KF5Activities_autogen/EWIEGA46WW/moc_consumer.cpp:253
[...]
#9  0x00007fa75f411d45 in KActivities::ActivitiesCache::serviceStatusChanged (this=this@entry=0x55df19128d20, _t1=<optimized out>, _t1@entry=KActivities::Consumer::Running) at ./obj-x86_64-linux-gnu/src/lib/KF5Activities_autogen/EWIEGA46WW/moc_activitiescache_p.cpp:412
#10 0x00007fa75f42b046 in KActivities::ActivitiesCache::setAllActivities (this=this@entry=0x55df19128d20, _activities=...) at ./src/lib/activitiescache_p.cpp:270

*** Bug 441607 has been marked as a duplicate of this bug. ***

Created attachment 141512 [details]
New crash information added by DrKonqi

plasmashell (5.22.5) using Qt 5.15.2

Just logged in normally on the wayland session.

-- Backtrace (Reduced):
#6  0x00007f63a9b1e810 in QScreen::name (this=0x558977dad340) at kernel/qscreen.cpp:195
#7  0x00005589772bd38a in ShellCorona::addOutput (this=this@entry=0x558977deb030, screen=<optimized out>, screen@entry=0x558977dad340) at /usr/src/debug/plasma5-workspace-5.22.5-1.1.x86_64/shell/shellcorona.cpp:1251
#8  0x00005589772be00b in ShellCorona::load (this=<optimized out>) at /usr/src/debug/plasma5-workspace-5.22.5-1.1.x86_64/shell/shellcorona.cpp:701
#9  0x00007f63a96d4033 in QtPrivate::QSlotObjectBase::call (a=0x7ffd3535ca60, r=0x558977deb030, this=0x558977fa9fa0) at ../../include/QtCore/../../src/corelib/kernel/qobjectdefs_impl.h:398
#10 doActivate<false> (sender=0x558977f44450, signal_index=4, argv=0x7ffd3535ca60) at kernel/qobject.cpp:3886

*** Bug 442442 has been marked as a duplicate of this bug. ***

Created attachment 142325 [details]
New crash information added by DrKonqi

plasmashell (5.22.5) using Qt 5.15.3

- What I was doing when the application crashed:
1) Connect HDMI
2) Overlay asks for screen layout
3) Choose "unified"
4) Switch to second screen only (by drag drop screens and disable main)
5) Unplug HDMI port on PC
6) Main screen switches on again but only mouse active and screen is black

-- Backtrace (Reduced):
#4  0x00007f6638447c66 in QScreen::name (this=0x55bcfcff8580) at kernel/qscreen.cpp:195
#5  0x000055bcfc4d3a64 in ShellCorona::addOutput (this=this@entry=0x55bcfd2829c0, screen=<optimized out>, screen@entry=0x55bcfcff8580) at ./shell/shellcorona.cpp:1251
#6  0x000055bcfc4ddf33 in ShellCorona::load (this=0x55bcfd2829c0) at ./shell/shellcorona.cpp:701
#7  0x00007f6638073d9e in QtPrivate::QSlotObjectBase::call (a=0x7fffd6197d20, r=0x55bcfd2829c0, this=0x55bcfd3284b0) at ../../include/QtCore/../../src/corelib/kernel/qobjectdefs_impl.h:398
#8  doActivate<false> (sender=0x55bcfd2ec670, signal_index=4, argv=0x7fffd6197d20) at kernel/qobject.cpp:3886

Created attachment 142349 [details]
attachment-28063-0.html

Hi, I am not a programmer at all but as far as I understand this screen
issue has persisted for a while and has not been resolved. If someone wants
to chat and let me know a suitable time I could switch computer off and on
from boot to get error logs that may be useful to solve issues.

Thanks

Philip

On Mon, 11 Oct 2021, 10:23 Philippe GIBSON, <bugzilla_noreply@kde.org>
wrote:

> https://bugs.kde.org/show_bug.cgi?id=421700
>
> --- Comment #40 from Philippe GIBSON <philippeveteagibson@gmail.com> ---
> Created attachment 142325 [details]
>   --> https://bugs.kde.org/attachment.cgi?id=142325&action=edit
> New crash information added by DrKonqi
>
> plasmashell (5.22.5) using Qt 5.15.3
>
> - What I was doing when the application crashed:
> 1) Connect HDMI
> 2) Overlay asks for screen layout
> 3) Choose "unified"
> 4) Switch to second screen only (by drag drop screens and disable main)
> 5) Unplug HDMI port on PC
> 6) Main screen switches on again but only mouse active and screen is black
>
> -- Backtrace (Reduced):
> #4  0x00007f6638447c66 in QScreen::name (this=0x55bcfcff8580) at
> kernel/qscreen.cpp:195
> #5  0x000055bcfc4d3a64 in ShellCorona::addOutput
> (this=this@entry=0x55bcfd2829c0, screen=<optimized out>,
> screen@entry=0x55bcfcff8580) at ./shell/shellcorona.cpp:1251
> #6  0x000055bcfc4ddf33 in ShellCorona::load (this=0x55bcfd2829c0) at
> ./shell/shellcorona.cpp:701
> #7  0x00007f6638073d9e in QtPrivate::QSlotObjectBase::call
> (a=0x7fffd6197d20,
> r=0x55bcfd2829c0, this=0x55bcfd3284b0) at
> ../../include/QtCore/../../src/corelib/kernel/qobjectdefs_impl.h:398
> #8  doActivate<false> (sender=0x55bcfd2ec670, signal_index=4,
> argv=0x7fffd6197d20) at kernel/qobject.cpp:3886
>
> --
> You are receiving this mail because:
> You are on the CC list for the bug.

*** Bug 443718 has been marked as a duplicate of this bug. ***

*** Bug 443782 has been marked as a duplicate of this bug. ***

*** Bug 444059 has been marked as a duplicate of this bug. ***

*** Bug 444096 has been marked as a duplicate of this bug. ***

*** Bug 444745 has been marked as a duplicate of this bug. ***

*** Bug 444400 has been marked as a duplicate of this bug. ***

Not sure if this applies, but my desktop locked up when I unplugged my HDMI, then replugged.

My Kickoff launcher was responding, mouse cursor was responding, but everything else isn't

Thread 10 (Thread 0x7f51d6ace700 (LWP 4498)):
#0  0x00007f51dc7daaff in __GI___poll (fds=0x7f51c8004e60, nfds=1, timeout=-1) at ../sysdeps/unix/sysv/linux/poll.c:29
#1  0x00007f51db08136e in ?? () from /lib/x86_64-linux-gnu/libglib-2.0.so.0
#2  0x00007f51db0814a3 in g_main_context_iteration () from /lib/x86_64-linux-gnu/libglib-2.0.so.0
#3  0x00007f51dcdaa602 in QEventDispatcherGlib::processEvents(QFlags<QEventLoop::ProcessEventsFlag>) () from /lib/x86_64-linux-gnu/libQt5Core.so.5
#4  0x00007f51dcd4e8ab in QEventLoop::exec(QFlags<QEventLoop::ProcessEventsFlag>) () from /lib/x86_64-linux-gnu/libQt5Core.so.5
#5  0x00007f51dcb682c2 in QThread::exec() () from /lib/x86_64-linux-gnu/libQt5Core.so.5
#6  0x00007f51de37b549 in ?? () from /lib/x86_64-linux-gnu/libQt5Qml.so.5
#7  0x00007f51dcb6945c in ?? () from /lib/x86_64-linux-gnu/libQt5Core.so.5
#8  0x00007f51dbab3609 in start_thread (arg=<optimized out>) at pthread_create.c:477
#9  0x00007f51dc7e7293 in clone () at ../sysdeps/unix/sysv/linux/x86_64/clone.S:95

Thread 9 (Thread 0x7f51ce7fc700 (LWP 4544)):
#0  futex_wait_cancelable (private=<optimized out>, expected=0, futex_word=0x561d770ba828) at ../sysdeps/nptl/futex-internal.h:183
#1  __pthread_cond_wait_common (abstime=0x0, clockid=0, mutex=0x561d770ba7d8, cond=0x561d770ba800) at pthread_cond_wait.c:508
#2  __pthread_cond_wait (cond=0x561d770ba800, mutex=0x561d770ba7d8) at pthread_cond_wait.c:638
#3  0x00007f51d479fa4b in ?? () from /usr/lib/x86_64-linux-gnu/dri/i965_dri.so
#4  0x00007f51d479f64b in ?? () from /usr/lib/x86_64-linux-gnu/dri/i965_dri.so
#5  0x00007f51dbab3609 in start_thread (arg=<optimized out>) at pthread_create.c:477
#6  0x00007f51dc7e7293 in clone () at ../sysdeps/unix/sysv/linux/x86_64/clone.S:95

Thread 8 (Thread 0x7f51bb541700 (LWP 5423)):
#0  futex_wait_cancelable (private=<optimized out>, expected=0, futex_word=0x561d77ce7b60) at ../sysdeps/nptl/futex-internal.h:183
#1  __pthread_cond_wait_common (abstime=0x0, clockid=0, mutex=0x561d77ce7b10, cond=0x561d77ce7b38) at pthread_cond_wait.c:508
#2  __pthread_cond_wait (cond=0x561d77ce7b38, mutex=0x561d77ce7b10) at pthread_cond_wait.c:638
#3  0x00007f51dcb6f5cb in QWaitCondition::wait(QMutex*, QDeadlineTimer) () from /lib/x86_64-linux-gnu/libQt5Core.so.5
#4  0x00007f51de7dac24 in ?? () from /lib/x86_64-linux-gnu/libQt5Quick.so.5
#5  0x00007f51de7db099 in ?? () from /lib/x86_64-linux-gnu/libQt5Quick.so.5
#6  0x00007f51dcb6945c in ?? () from /lib/x86_64-linux-gnu/libQt5Core.so.5
#7  0x00007f51dbab3609 in start_thread (arg=<optimized out>) at pthread_create.c:477
#8  0x00007f51dc7e7293 in clone () at ../sysdeps/unix/sysv/linux/x86_64/clone.S:95

Thread 7 (Thread 0x7f51aa7fe700 (LWP 4879)):
#0  0x00007f51dc7daaff in __GI___poll (fds=0x7f5198008a10, nfds=1, timeout=-1) at ../sysdeps/unix/sysv/linux/poll.c:29
#1  0x00007f51db08136e in ?? () from /lib/x86_64-linux-gnu/libglib-2.0.so.0
#2  0x00007f51db0814a3 in g_main_context_iteration () from /lib/x86_64-linux-gnu/libglib-2.0.so.0
#3  0x00007f51dcdaa602 in QEventDispatcherGlib::processEvents(QFlags<QEventLoop::ProcessEventsFlag>) () from /lib/x86_64-linux-gnu/libQt5Core.so.5
#4  0x00007f51dcd4e8ab in QEventLoop::exec(QFlags<QEventLoop::ProcessEventsFlag>) () from /lib/x86_64-linux-gnu/libQt5Core.so.5
#5  0x00007f51dcb682c2 in QThread::exec() () from /lib/x86_64-linux-gnu/libQt5Core.so.5
#6  0x00007f51de7153fa in ?? () from /lib/x86_64-linux-gnu/libQt5Quick.so.5
#7  0x00007f51dcb6945c in ?? () from /lib/x86_64-linux-gnu/libQt5Core.so.5
#8  0x00007f51dbab3609 in start_thread (arg=<optimized out>) at pthread_create.c:477
#9  0x00007f51dc7e7293 in clone () at ../sysdeps/unix/sysv/linux/x86_64/clone.S:95

Thread 6 (Thread 0x7f51cffff700 (LWP 4540)):
#0  futex_wait_cancelable (private=<optimized out>, expected=0, futex_word=0x561d770ba828) at ../sysdeps/nptl/futex-internal.h:183
#1  __pthread_cond_wait_common (abstime=0x0, clockid=0, mutex=0x561d770ba7d8, cond=0x561d770ba800) at pthread_cond_wait.c:508
#2  __pthread_cond_wait (cond=0x561d770ba800, mutex=0x561d770ba7d8) at pthread_cond_wait.c:638
#3  0x00007f51d479fa4b in ?? () from /usr/lib/x86_64-linux-gnu/dri/i965_dri.so
#4  0x00007f51d479f64b in ?? () from /usr/lib/x86_64-linux-gnu/dri/i965_dri.so
#5  0x00007f51dbab3609 in start_thread (arg=<optimized out>) at pthread_create.c:477
#6  0x00007f51dc7e7293 in clone () at ../sysdeps/unix/sysv/linux/x86_64/clone.S:95

Thread 5 (Thread 0x7f51cf7fe700 (LWP 4541)):
#0  futex_wait_cancelable (private=<optimized out>, expected=0, futex_word=0x561d770ba828) at ../sysdeps/nptl/futex-internal.h:183
#1  __pthread_cond_wait_common (abstime=0x0, clockid=0, mutex=0x561d770ba7d8, cond=0x561d770ba800) at pthread_cond_wait.c:508
#2  __pthread_cond_wait (cond=0x561d770ba800, mutex=0x561d770ba7d8) at pthread_cond_wait.c:638
#3  0x00007f51d479fa4b in ?? () from /usr/lib/x86_64-linux-gnu/dri/i965_dri.so
#4  0x00007f51d479f64b in ?? () from /usr/lib/x86_64-linux-gnu/dri/i965_dri.so
#5  0x00007f51dbab3609 in start_thread (arg=<optimized out>) at pthread_create.c:477
#6  0x00007f51dc7e7293 in clone () at ../sysdeps/unix/sysv/linux/x86_64/clone.S:95

Thread 4 (Thread 0x7f51ceffd700 (LWP 4543)):
#0  futex_wait_cancelable (private=<optimized out>, expected=0, futex_word=0x561d770ba82c) at ../sysdeps/nptl/futex-internal.h:183
#1  __pthread_cond_wait_common (abstime=0x0, clockid=0, mutex=0x561d770ba7d8, cond=0x561d770ba800) at pthread_cond_wait.c:508
#2  __pthread_cond_wait (cond=0x561d770ba800, mutex=0x561d770ba7d8) at pthread_cond_wait.c:638
#3  0x00007f51d479fa4b in ?? () from /usr/lib/x86_64-linux-gnu/dri/i965_dri.so
#4  0x00007f51d479f64b in ?? () from /usr/lib/x86_64-linux-gnu/dri/i965_dri.so
#5  0x00007f51dbab3609 in start_thread (arg=<optimized out>) at pthread_create.c:477
#6  0x00007f51dc7e7293 in clone () at ../sysdeps/unix/sysv/linux/x86_64/clone.S:95

Thread 3 (Thread 0x7f51bbfff700 (LWP 4638)):
#0  0x00007f51dc7daaff in __GI___poll (fds=0x7f51ac004a60, nfds=1, timeout=-1) at ../sysdeps/unix/sysv/linux/poll.c:29
#1  0x00007f51db08136e in ?? () from /lib/x86_64-linux-gnu/libglib-2.0.so.0
#2  0x00007f51db0814a3 in g_main_context_iteration () from /lib/x86_64-linux-gnu/libglib-2.0.so.0
#3  0x00007f51dcdaa602 in QEventDispatcherGlib::processEvents(QFlags<QEventLoop::ProcessEventsFlag>) () from /lib/x86_64-linux-gnu/libQt5Core.so.5
#4  0x00007f51dcd4e8ab in QEventLoop::exec(QFlags<QEventLoop::ProcessEventsFlag>) () from /lib/x86_64-linux-gnu/libQt5Core.so.5
#5  0x00007f51dcb682c2 in QThread::exec() () from /lib/x86_64-linux-gnu/libQt5Core.so.5
#6  0x00007f51dcb6945c in ?? () from /lib/x86_64-linux-gnu/libQt5Core.so.5
#7  0x00007f51dbab3609 in start_thread (arg=<optimized out>) at pthread_create.c:477
#8  0x00007f51dc7e7293 in clone () at ../sysdeps/unix/sysv/linux/x86_64/clone.S:95

Thread 2 (Thread 0x7f51d7d4b700 (LWP 4288)):
#0  __GI___libc_read (nbytes=16, buf=0x7f51d7d4a9a0, fd=9) at ../sysdeps/unix/sysv/linux/read.c:26
#1  __GI___libc_read (fd=9, buf=0x7f51d7d4a9a0, nbytes=16) at ../sysdeps/unix/sysv/linux/read.c:24
#2  0x00007f51db0c9b2f in ?? () from /lib/x86_64-linux-gnu/libglib-2.0.so.0
#3  0x00007f51db080ebe in g_main_context_check () from /lib/x86_64-linux-gnu/libglib-2.0.so.0
#4  0x00007f51db081312 in ?? () from /lib/x86_64-linux-gnu/libglib-2.0.so.0
#5  0x00007f51db0814a3 in g_main_context_iteration () from /lib/x86_64-linux-gnu/libglib-2.0.so.0
#6  0x00007f51dcdaa61b in QEventDispatcherGlib::processEvents(QFlags<QEventLoop::ProcessEventsFlag>) () from /lib/x86_64-linux-gnu/libQt5Core.so.5
#7  0x00007f51dcd4e8ab in QEventLoop::exec(QFlags<QEventLoop::ProcessEventsFlag>) () from /lib/x86_64-linux-gnu/libQt5Core.so.5
#8  0x00007f51dcb682c2 in QThread::exec() () from /lib/x86_64-linux-gnu/libQt5Core.so.5
#9  0x00007f51dd6dbf4b in ?? () from /lib/x86_64-linux-gnu/libQt5DBus.so.5
#10 0x00007f51dcb6945c in ?? () from /lib/x86_64-linux-gnu/libQt5Core.so.5
#11 0x00007f51dbab3609 in start_thread (arg=<optimized out>) at pthread_create.c:477
#12 0x00007f51dc7e7293 in clone () at ../sysdeps/unix/sysv/linux/x86_64/clone.S:95

Thread 1 (Thread 0x7f51d892d9c0 (LWP 4260)):
#0  __GI_raise (sig=<optimized out>) at ../sysdeps/unix/sysv/linux/raise.c:50
#1  0x00007f51dec51e95 in KCrash::defaultCrashHandler(int) () from /lib/x86_64-linux-gnu/libKF5Crash.so.5
#2  <signal handler called>
#3  0x00007f51de816292 in QQuickItemPrivate::addToDirtyList() () from /lib/x86_64-linux-gnu/libQt5Quick.so.5
#4  0x00007f51de816336 in QQuickItemPrivate::dirty(QQuickItemPrivate::DirtyType) () from /lib/x86_64-linux-gnu/libQt5Quick.so.5
#5  0x00007f51de81797b in QQuickItem::setSize(QSizeF const&) () from /lib/x86_64-linux-gnu/libQt5Quick.so.5
#6  0x00007f51de806ea9 in ?? () from /lib/x86_64-linux-gnu/libQt5Quick.so.5
#7  0x00007f51de81d6b4 in QQuickItem::geometryChanged(QRectF const&, QRectF const&) () from /lib/x86_64-linux-gnu/libQt5Quick.so.5
#8  0x00007f51df12d32d in PlasmaQuick::AppletQuickItem::geometryChanged(QRectF const&, QRectF const&) () from /lib/x86_64-linux-gnu/libKF5PlasmaQuick.so.5
#9  0x00007f51de8179ed in QQuickItem::setSize(QSizeF const&) () from /lib/x86_64-linux-gnu/libQt5Quick.so.5
#10 0x00007f51df138da8 in ?? () from /lib/x86_64-linux-gnu/libKF5PlasmaQuick.so.5
#11 0x0000561d76a670b3 in ShellCorona::addOutput (this=0x561d76fcb990, screen=<optimized out>) at ./shell/shellcorona.cpp:1228
#12 0x00007f51dcd86dce in ?? () from /lib/x86_64-linux-gnu/libQt5Core.so.5
#13 0x00007f51dd125c66 in QGuiApplication::screenAdded(QScreen*) () from /lib/x86_64-linux-gnu/libQt5Gui.so.5
#14 0x00007f51dabd8868 in QtWaylandClient::QWaylandDisplay::handleScreenInitialized(QtWaylandClient::QWaylandScreen*) () from /lib/x86_64-linux-gnu/libQt5WaylandClient.so.5
#15 0x00007f51dabe87a3 in QtWaylandClient::QWaylandScreen::maybeInitialize() () from /lib/x86_64-linux-gnu/libQt5WaylandClient.so.5
#16 0x00007f51db029ff5 in ?? () from /lib/x86_64-linux-gnu/libffi.so.7
#17 0x00007f51db02940a in ?? () from /lib/x86_64-linux-gnu/libffi.so.7
#18 0x00007f51dc6733a8 in ?? () from /lib/x86_64-linux-gnu/libwayland-client.so.0
#19 0x00007f51dc66fc48 in ?? () from /lib/x86_64-linux-gnu/libwayland-client.so.0
#20 0x00007f51dc67121c in wl_display_dispatch_queue_pending () from /lib/x86_64-linux-gnu/libwayland-client.so.0
#21 0x00007f51dabd7335 in QtWaylandClient::QWaylandDisplay::flushRequests() () from /lib/x86_64-linux-gnu/libQt5WaylandClient.so.5
#22 0x00007f51dcd86e00 in ?? () from /lib/x86_64-linux-gnu/libQt5Core.so.5
#23 0x00007f51dcd8ae53 in QSocketNotifier::activated(QSocketDescriptor, QSocketNotifier::Type, QSocketNotifier::QPrivateSignal) () from /lib/x86_64-linux-gnu/libQt5Core.so.5
#24 0x00007f51dcd8b5f3 in QSocketNotifier::event(QEvent*) () from /lib/x86_64-linux-gnu/libQt5Core.so.5
#25 0x00007f51dda61dc3 in QApplicationPrivate::notify_helper(QObject*, QEvent*) () from /lib/x86_64-linux-gnu/libQt5Widgets.so.5
#26 0x00007f51dda6abb8 in QApplication::notify(QObject*, QEvent*) () from /lib/x86_64-linux-gnu/libQt5Widgets.so.5
#27 0x00007f51dcd4fdaa in QCoreApplication::notifyInternal2(QObject*, QEvent*) () from /lib/x86_64-linux-gnu/libQt5Core.so.5
#28 0x00007f51dcdab205 in ?? () from /lib/x86_64-linux-gnu/libQt5Core.so.5
#29 0x00007f51db08117d in g_main_context_dispatch () from /lib/x86_64-linux-gnu/libglib-2.0.so.0
#30 0x00007f51db081400 in ?? () from /lib/x86_64-linux-gnu/libglib-2.0.so.0
#31 0x00007f51db0814a3 in g_main_context_iteration () from /lib/x86_64-linux-gnu/libglib-2.0.so.0
#32 0x00007f51dcdaa602 in QEventDispatcherGlib::processEvents(QFlags<QEventLoop::ProcessEventsFlag>) () from /lib/x86_64-linux-gnu/libQt5Core.so.5
#33 0x00007f51dcd4e8ab in QEventLoop::exec(QFlags<QEventLoop::ProcessEventsFlag>) () from /lib/x86_64-linux-gnu/libQt5Core.so.5
#34 0x00007f51dcd56a64 in QCoreApplication::exec() () from /lib/x86_64-linux-gnu/libQt5Core.so.5
#35 0x0000561d76a3ecf5 in main (argc=<optimized out>, argv=<optimized out>) at ./shell/main.cpp:238

*** Bug 444963 has been marked as a duplicate of this bug. ***

I can reproduce this also with the following command:

    qdbus org.kde.KWin /KWin reconfigure

The underlying problem is that during a DesktopView::show() call in ShellCorona::addOutput(), Qt decides to flush events and delete the QScreen on stack.

Thanks for that valuable observation, hluk! Any idea how we could fix this? Would you be interested in submitting a fix to either Plasma or Qt?

(In reply to Nate Graham from comment #51)
> Thanks for that valuable observation, hluk! Any idea how we could fix this?
> Would you be interested in submitting a fix to either Plasma or Qt?

Patch posted here: https://invent.kde.org/plasma/plasma-workspace/-/merge_requests/1192

*** Bug 445368 has been marked as a duplicate of this bug. ***

Turns out this needs to be fixed in Qt. Thankfully, this is getting done in: https://codereview.qt-project.org/c/qt/qtwayland/+/381271!

Created attachment 143595 [details]
attachment-3072-0.html

Very good to hear this is being fixed.

Nate, if you see this email,, can you guide me or ask someone how to send
bug reports.

Thanks

Philip

On Mon, 15 Nov 2021, 18:21 Nate Graham, <bugzilla_noreply@kde.org> wrote:

> https://bugs.kde.org/show_bug.cgi?id=421700
>
> Nate Graham <nate@kde.org> changed:
>
>            What    |Removed                     |Added
>
> ----------------------------------------------------------------------------
>                 URL|                            |
> https://codereview.qt-proje
>                    |                            |
> ct.org/c/qt/qtwayland/+/381
>                    |                            |271
>          Resolution|---                         |UPSTREAM
>              Status|CONFIRMED                   |RESOLVED
>
> --- Comment #54 from Nate Graham <nate@kde.org> ---
> Turns out this needs to be fixed in Qt. Thankfully, this is getting done
> in:
> https://codereview.qt-project.org/c/qt/qtwayland/+/381271!
>
> --
> You are receiving this mail because:
> You are on the CC list for the bug.

See https://community.kde.org/Get_Involved/Issue_Reporting

Is there similar report for X11? 

plasma panel crashes for all the time on hdmi connect

plasmashell[1522]: ASSERT: "last < rowCount(parent)" in file /storage/gentoo/tmp/portage/dev-qt/qtcore-5.15.2-r10/work/qtbase-c2ea67ecefe049f6e9bb8f910d7f9c60319d8619/src/corelib/itemmodels/qabstractitemmodel.cpp, line 2815


                                                  #5  0x00007f5659a71ac2 raise (libc.so.6 + 0x3dac2)
                                                  #6  0x00007f5659a5c449 abort (libc.so.6 + 0x28449)
                                                  #7  0x00007f5659ef7584 qt_message_fatal (libQt5Core.so.5 + 0xb8584)
                                                  #8  0x00007f5659ef38a6 _ZNK14QMessageLogger5fatalEPKcz (libQt5Core.so.5 + 0xb48a6)
                                                  #9  0x00007f5659eea244 _Z9qt_assertPKcS0_i (libQt5Core.so.5 + 0xab244)
                                                  #10 0x00007f565a1130cb _ZN18QAbstractItemModel15beginRemoveRowsERK11QModelIndexii (libQt5Core.so.5 + 0x2d40cb)
                                                  #11 0x00007f56442687db n/a (libfolderplugin.so + 0x417db)
                                                  #12 0x00007f565a192529 _ZN9QtPrivate15QSlotObjectBase4callEP7QObjectPPv (libQt5Core.so.5 + 0x353529)
                                                  #13 0x00007f565a1d5ee2 _Z10doActivateILb0EEvP7QObjectiPPv (libQt5Core.so.5 + 0x396ee2)
                                                  #14 0x00007f565a1cf1e5 _ZN11QMetaObject8activateEP7QObjectPKS_iPPv (libQt5Core.so.5 + 0x3901e5)
                                                  #15 0x00007f565a118888 _ZN18QAbstractItemModel20rowsAboutToBeRemovedERK11QModelIndexiiNS_14QPrivateSignalE (libQt5Core.so.5 + 0x2d9888)
                                                  #16 0x00007f565a11311e _ZN18QAbstractItemModel15beginRemoveRowsERK11QModelIndexii (libQt5Core.so.5 + 0x2d411e)
                                                  #17 0x00007f565a14382b _ZN28QSortFilterProxyModelPrivate21remove_proxy_intervalER7QVectorIiES2_iiRK11QModelIndexN2Qt11OrientationEb (libQt5Core.so.>
                                                  #18 0x00007f565a14376a _ZN28QSortFilterProxyModelPrivate19remove_source_itemsER7QVectorIiES2_RKS1_RK11QModelIndexN2Qt11OrientationEb (libQt5Core.so>
                                                  #19 0x00007f565a145c64 _ZN28QSortFilterProxyModelPrivate21handle_filter_changedER7QVectorIiES2_RK11QModelIndexN2Qt11OrientationE (libQt5Core.so.5 +>
                                                  #20 0x00007f565a145851 _ZN28QSortFilterProxyModelPrivate14filter_changedERK11QModelIndex (libQt5Core.so.5 + 0x306851)
                                                  #21 0x00007f565a14bc20 _ZN21QSortFilterProxyModel16invalidateFilterEv (libQt5Core.so.5 + 0x30cc20)
                                                  #22 0x00007f565a192529 _ZN9QtPrivate15QSlotObjectBase4callEP7QObjectPPv (libQt5Core.so.5 + 0x353529)
                                                  #23 0x00007f565a1d5ee2 _Z10doActivateILb0EEvP7QObjectiPPv (libQt5Core.so.5 + 0x396ee2)
                                                  #24 0x00007f565a1cf1e5 _ZN11QMetaObject8activateEP7QObjectPKS_iPPv (libQt5Core.so.5 + 0x3901e5)
                                                  #25 0x00007f5644273c90 n/a (libfolderplugin.so + 0x4cc90)

*** Bug 445464 has been marked as a duplicate of this bug. ***

*** Bug 445646 has been marked as a duplicate of this bug. ***

*** Bug 445876 has been marked as a duplicate of this bug. ***

*** Bug 446039 has been marked as a duplicate of this bug. ***

*** Bug 446807 has been marked as a duplicate of this bug. ***

*** Bug 446947 has been marked as a duplicate of this bug. ***

*** Bug 447975 has been marked as a duplicate of this bug. ***

*** Bug 447781 has been marked as a duplicate of this bug. ***

Created attachment 146648 [details]
New crash information added by DrKonqi

plasmashell (5.24.0) using Qt 5.15.3

- What I was doing when the application crashed:
Login to wayland session

- Unusual behavior I noticed:

This is from dmesg:

[ 2713.233599] usb 5-2.1.5: Product: USB Billboard Device   
[ 2713.233601] usb 5-2.1.5: Manufacturer: VIA Labs, Inc.         
[ 2713.233603] usb 5-2.1.5: SerialNumber: 0000000000000001
[ 2713.351129] keepassxc[3952]: segfault at 20 ip 00007f17528cdcde sp 00007ffed1c73888 error 4 in libQt5WaylandClient.so.5.15.3[7f1752885000+c4000]
[ 2713.351144] Code: d0 75 09 c3 0f 1f 84 00 00 00 00 00 ff e0 66 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 00 f3 0f 1e fa 48 8b 07 48 8d 15 42 f3 ff ff <48> 8b 40 20 48 39 d0 75 09 c3 0f 1f 84 00 00 00 00 00 ff e0 66 66
[ 2713.356585] kscreenlocker_g[14536]: segfault at 20 ip 00007f5935f9ccde sp 00007ffec2d21168 error 4 in libQt5WaylandClient.so.5.15.3[7f5935f54000+c4000]
[ 2713.356597] Code: d0 75 09 c3 0f 1f 84 00 00 00 00 00 ff e0 66 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 00 f3 0f 1e fa 48 8b 07 48 8d 15 42 f3 ff ff <48> 8b 40 20 48 39 d0 75 09 c3 0f 1f 84 00 00 00 00 00 ff e0 66 66
[ 2713.373084] kwin_wayland[3410]: segfault at 0 ip 00007f53dc156115 sp 00007ffc85e89cc0 error 4 in KWinWaylandDrmBackend.so[7f53dc11c000+48000]
[ 2713.373093] Code: 48 63 55 04 48 8b 45 10 0f 29 04 24 48 8d 14 92 48 8d 5c 05 00 48 8d 04 90 48 01 c5 48 39 eb 74 6a 0f 1f 40 00 49 8b 3e 8b 33 <48> 8b 07 ff 90 28 01 00 00 84 c0 74 4b 8b 43 08 8b 53 0c 48 8d 4b
[ 2713.443808] r8152 6-2.1.2:1.0 enx98fa9b46c7bd: renamed from eth0
[ 2714.584783] usbcore: registered new interface driver snd-usb-audio
[ 2714.821232] input: Lenovo ThinkPad Thunderbolt 3 Dock USB Audio as /devices/pci0000:00/0000:00:1c.4/0000:02:00.0/0000:03:01.0/0000:05:00.0/0000:06:02.0/0000:07:00.0/usb5/5-2/5-2.1/5-2.1.1/5-2.1.1.2/5-2.1.1.2:1.3/0003:17EF:3083.0007/input/input29
[ 2714.881018] hid-generic 0003:17EF:3083.0007: input,hidraw1: USB HID v1.11 Device [Lenovo ThinkPad Thunderbolt 3 Dock USB Audio] on usb-0000:07:00.0-2.1.1.2/input3
[ 2715.215142] IPv6: ADDRCONF(NETDEV_CHANGE): enx98fa9b46c7bd: link becomes ready
[ 2715.215506] r8152 6-2.1.2:1.0 enx98fa9b46c7bd: carrier on
[ 2716.079488] r8152 6-2.1.2:1.0 enx98fa9b46c7bd: carrier off
[ 2718.543110] r8152 6-2.1.2:1.0 enx98fa9b46c7bd: carrier on
[ 2725.515851] i915 0000:00:02.0: [drm] *ERROR* mstb 0000000015dd9b1a port 1: DPCD read on addr 0x4b0 for 1 bytes NAKed
seattle ~ ❯

-- Backtrace (Reduced):
#4  QScreen::geometry (this=0x0) at kernel/qscreen.cpp:413
#5  0x00005594379de6c5 in DesktopView::screenGeometryChanged (this=0x5594393a7f80) at /usr/include/c++/9/bits/atomic_base.h:413
#6  0x00007fa16ff3c1be in QtPrivate::QSlotObjectBase::call (a=0x7ffcb6e9b950, r=0x5594393a7f80, this=0x559439383b90) at ../../include/QtCore/../../src/corelib/kernel/qobjectdefs_impl.h:398
#7  doActivate<false> (sender=0x559438947aa0, signal_index=3, argv=0x7ffcb6e9b950) at kernel/qobject.cpp:3886
[...]
#9  0x00007fa17074e636 in QScreen::geometryChanged (this=this@entry=0x559438947aa0, _t1=...) at .moc/moc_qscreen.cpp:372

*** Bug 485275 has been marked as a duplicate of this bug. ***