Bug 428987 - Reordering task manager tasks on the panel make the wayland session crash
Summary: Reordering task manager tasks on the panel make the wayland session crash
Status: RESOLVED DUPLICATE of bug 430111
Alias: None
Product: plasmashell
Classification: Plasma
Component: Task Manager and Icons-Only Task Manager widgets (show other bugs)
Version: 5.20.3
Platform: Neon Linux
: VHI normal
Target Milestone: 1.0
Assignee: Eike Hein
URL:
Keywords: wayland-only
Depends on:
Blocks:
 
Reported: 2020-11-11 20:19 UTC by Nicola Jelmorini
Modified: 2020-12-08 14:41 UTC (History)
5 users (show)

See Also:
Latest Commit:
Version Fixed In:
Sentry Crash Report:


Attachments
coredumpctl (979 bytes, text/plain)
2020-11-17 19:58 UTC, Nicola Jelmorini
Details
gdb dump of kwin-wayland (1.69 KB, text/plain)
2020-11-18 19:30 UTC, Nicola Jelmorini
Details

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Description Nicola Jelmorini 2020-11-11 20:19:46 UTC
SUMMARY
If I want to reorder my running apps on the panel, immediately after I release the first app, the session closes and the login screen shows up.

STEPS TO REPRODUCE
1. Open two or more apps
2. Clic on one app on the panel and drag it in another position
3. Release the mouse button and the session crashes

OBSERVED RESULT
The current session is closed and the login screen shows up.

EXPECTED RESULT
The apps on the panel should simply be reordered.


SOFTWARE/OS VERSIONS
Windows: 
macOS: 
Linux/KDE Plasma: KDE Neon 20.04
(available in About System)
KDE Plasma Version: 5.20.3
KDE Frameworks Version: 5.75.0
Qt Version: 5.15.1

ADDITIONAL INFORMATION
I'm running a Wayland session.
Comment 1 Nate Graham 2020-11-11 21:29:35 UTC
Are these pinned task manager icons or icon applets which held app launchers?

Also please attach a backtrace of the crash so we can figure out what's happening. See https://community.kde.org/Get_Involved/Issue_Reporting#Crash_reports_must_include_backtraces.
Comment 2 Nicola Jelmorini 2020-11-12 19:04:47 UTC
@Nate Graham 
Are these pinned task manager icons or icon applets which held app launchers?
==> let say I open two apps: Dolphin and KSysGuard. In the panel I see the two apps (rectangular icon with the name of the app), and are those that I can reorder with a drag & drop. I'm not sure if they are pinned icons or icon applets.

Also please attach a backtrace of the crash
==> well, I'm afraid it's a bit too much "technical" for me, sorry. Moreover the problem is that I don't know what to trace. The entire session ends suddenly, but I don't know if the crash happens in the "Wayland Session" as a whole, or in the panel. DrKonqi doesn't show up.
Comment 3 Nate Graham 2020-11-12 21:44:21 UTC
Ah, so pinned apps. Thanks.

Cannot reproduce.
Comment 4 Nicola Jelmorini 2020-11-15 19:17:28 UTC
I have recorded a brief video of the screen of my PC with my mobile phone when the issue happens. You can watch the video at the following link (the file is too big to upload it as attachment).
https://www.mycloud.ch/l/L005D87F1F9960921DE74DB4FE0B00BD09430A8F31507A77A3530AB97D830C15

I can also add that this same issue happens on another PC, so it's not linked to this PC only.
Comment 5 Nate Graham 2020-11-16 21:27:20 UTC
Thanks for the video, that's helpful. Looks like you're using a Task Manager (not icons-only). Works for me FWIW.

Can you attach a backtrace of the crash? `coredumpctl` can retrieve it.
Comment 6 Nicola Jelmorini 2020-11-17 19:58:33 UTC
Created attachment 133405 [details]
coredumpctl
Comment 7 Nicola Jelmorini 2020-11-17 19:59:09 UTC
I have installed "systemd-coredumpctl" and reproduced the issue.
Then I have used the following command:

sudo coredumpctl info 1137 > coredump_wayland.txt

to save the dump of the PID 1137 (see attachment) listed as:

TIME                            PID   UID   GID SIG COREFILE  EXE
Tue 2020-11-17 20:36:26 CET    1137  1000  1000  11 truncated /usr/bin/kwin_wayland

First time I use coredumpctl. I hope this can be useful.
Comment 8 Nate Graham 2020-11-17 20:38:47 UTC
No worries. Here's what you do.

First, dump the core to a file:

coredumpctl --dump --output ~/Desktop/my_very_special_core.dump

Next, load it up in gdb:

gdb /usr/bin/kwin_wayland ~/Desktop/my_very_special_core.dump

Then type "bt". Copy and paste the output to a file, and attach that file.
Comment 9 Nicola Jelmorini 2020-11-18 19:30:08 UTC
Created attachment 133444 [details]
gdb dump of kwin-wayland
Comment 10 Nicola Jelmorini 2020-11-18 19:33:20 UTC
I have tried to run the commands you suggested (thanks!) 
I have uploaded the gdb output as attachment.
Comment 11 Nate Graham 2020-11-18 20:32:57 UTC
Aww man:

> BFD: warning: /home/nicola/Scrivania/coredump_wayland_1195.dump is truncated: expected core file size >= 2883301376, found: 2147483648
> Backtrace stopped: Cannot access memory at address 0x7fff5ae6f918
I hate this. :( It's so complicated to get a backtrace out of coredumpctl. :(

Thanks anyway.
Comment 12 Lars Veldscholte 2020-11-22 23:24:27 UTC
I have the exact same issue.

My system info: 

Operating System: Arch Linux
KDE Plasma Version: 5.20.3
KDE Frameworks Version: 5.76.0
Qt Version: 5.15.2
Kernel Version: 5.9.9-zen1-1-zen
OS Type: 64-bit
Processors: 12 × AMD Ryzen 5 PRO 4650U with Radeon Graphics
Memory: 14.9 GiB of RAM
Graphics Processor: AMD RENOIR

I also tried to retrieve a backtrace but got the same output as Nicola: 

> Backtrace stopped: Cannot access memory at address 0x7ffea621a6d0
Comment 13 Benjamin Smith 2020-11-23 03:05:54 UTC
This crash is also happening for me on Arch Linux. I have no pinned apps. The Plasma Wayland session crashes when trying to rearrange task manager buttons. The crash does not happen in a Plasma Xorg session. 

Plasma 5.20.3
Frameworks 5.76.0
Qt 5.15.2
Kernel 5.9.9-arch1-1 x86_64
Comment 14 Nate Graham 2020-11-23 16:39:28 UTC
Oof. Whole session crashes with a common workflow are no bueno. Raising to VHI.
Comment 15 David Edmundson 2020-11-23 16:52:49 UTC
No backtrace, not reproducible.

Marking as needsinfo.

> Raising to VHI.


Lets save this for only things that are hit commonly.
Comment 16 David Edmundson 2020-11-23 16:59:45 UTC
There were some d&d related fixes in kwayland in master since last release, potentially those fixed it
Comment 17 Lars Veldscholte 2020-11-23 17:01:12 UTC
Is there something I can try to get a valid backtrace? I'd glad to help.
Comment 18 Bug Janitor Service 2020-12-08 04:34:06 UTC
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!
Comment 19 Nate Graham 2020-12-08 14:41:09 UTC
*** This bug has been marked as a duplicate of bug 430111 ***