Bug 486053

Summary: Crashing when doing various windows actions in Kwin Wayland
Product: [Plasma] kwin Reporter: toadking
Component: generic-crashAssignee: KWin default assignee <kwin-bugs-null>
Status: RESOLVED UPSTREAM    
Severity: crash    
Priority: NOR    
Version First Reported In: 6.0.4   
Target Milestone: ---   
Platform: Arch Linux   
OS: Linux   
URL: https://codereview.qt-project.org/c/qt/qtdeclarative/+/576193
Latest Commit: Version Fixed/Implemented In:
Sentry Crash Report:
Attachments: crash backtrace

Description toadking 2024-04-24 03:31:40 UTC 
Created attachment 168855 [details]
crash backtrace

***
If you're not sure this is actually a bug, instead post about it at https://discuss.kde.org

If you're reporting a crash, attach a backtrace with debug symbols; see https://community.kde.org/Guidelines_and_HOWTOs/Debugging/How_to_create_useful_crash_reports
***

SUMMARY
Ever since an update a couple of days ago, my KDE desktop has been crashing significantly. I'm not sure of the exact update that causes the issue but on Plasma Wayland the Kwin process has started crashing when doing certain actions. Specifically alt-tabbing and dragging a window to the top of the screen to maximize it causes crashes. A backtrace is attached. X11 Plasma does not cause Kwin crashes.

STEPS TO REPRODUCE
1. Start Plasma with Wayland
2. Drag a window to the top of the screen to maximize it

OBSERVED RESULT
Crash

EXPECTED RESULT
No crash

SOFTWARE/OS VERSIONS
Linux/KDE Plasma: Archlinux - Kernel 6.8.7-arch1-1
(available in About System)
KDE Plasma Version: 6.0.4
KDE Frameworks Version: 6.1.0
Qt Version: 6.7.0

GPU: Nvidia RTX 2070
GPU Drivers: 550.76

ADDITIONAL INFORMATION
I'm also having issues with icons in the taskbar jumping around on hover but I don't know if those are related to this issue or not. This also also appears on X11 as well as Wayland.
Comment 1 toadking 2024-04-25 22:43:39 UTC 
Narrowed down the issue more. It seems like something set The Qt Quick renderer backend to software and the bugs were only appearing there.

From my ~/.config/kdeglobals file:

[QtQuickRendererSettings]
SceneGraphBackend=software

Removing those lines and logging out and back in again fixed both the crashing and the corrupted taskbar icons. No idea why/when that was set, tried looking it up and maybe it has something to do with this: https://discuss.kde.org/t/on-error-kde6-x11-switched-to-the-software-renderer-how-to-reverse/13241
Comment 2 Vlad Zahorodnii 2024-10-01 09:47:55 UTC 
This should be fixed in Qt 6.7.3.