Bug 492777

Summary:	Hang on big window size on Wayland.
Product:	[Plasma] kwin	Reporter:	alekseipesorin
Component:	wayland-generic	Assignee:	KWin default assignee <kwin-bugs-null>
Status:	RESOLVED WORKSFORME
Severity:	normal
Priority:	NOR
Version First Reported In:	6.1.4
Target Milestone:	---
Platform:	Arch Linux
OS:	Linux
Latest Commit:		Version Fixed/Implemented In:
Sentry Crash Report:
Attachments:	The exact revision of the offending application that I discovered this in.

Description alekseipesorin 2024-09-07 21:52:52 UTC

Created attachment 173420 [details]
The exact revision of the offending application that I discovered this in.

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***

SUMMARY
When window size is too big, Plasma shell becomes transparent and everything just hangs. I am not even sure if this is kwin related, but this doesn't appear reproduce on X11. Going to a tty as root and running `killall -9 kwin_wayland` crashes every user up but brings back the lock screen. Discovered when fucking around with PyQt6 for school purposes. This happened with the ALHP repository but I have confirmed it reproduces with Arch's default repositories.
I don't think a userspace program should be able to stop workflow either way.

STEPS TO REPRODUCE
1. Install PyQT6 and NumPy.
2. Run the attached file.
3. Press the Russian text button

OBSERVED RESULT
See SUMMARY.

EXPECTED RESULT
It either makes the window wide as expected, makes the window cap at a certain limit or 

SOFTWARE/OS VERSIONS
KDE Plasma Version: 6.1.4
KDE Frameworks Version: 6.5.0
Qt Version: 6.7.2

ADDITIONAL INFORMATION
Nun

Comment 1 Vlad Zahorodnii 2024-09-08 09:45:17 UTC

It can take a while to upload graphics buffer contents to an opengl texture if it's too big. There's also a question of texture limits. In my case, kwin doesn't hang, but it fails to upload texture data. Can you get kwin's backtrace when it hangs?

Comment 2 alekseipesorin 2024-09-08 12:26:16 UTC

(In reply to Vlad Zahorodnii from comment #1)
> It can take a while to upload graphics buffer contents to an opengl texture
> if it's too big. There's also a question of texture limits. In my case, kwin
> doesn't hang, but it fails to upload texture data. Can you get kwin's
> backtrace when it hangs?

How do I get the backtrace of an app that didn't crash?

Also, I experimented a little bit and 10000 renders instantly but 20000 is bad. I tried that on a different laptop but same GPU and same system (replaced SSD) and there it just hangs the app and not kwin for some reason, and then there are major graphical glitches where it blinks between completely black and 3 minute old buffer until I restart kwin.

Comment 3 Vlad Zahorodnii 2024-09-09 11:58:07 UTC

you'll need to ssh to your computer and attach a debugger, see https://community.kde.org/index.php?title=KWin/Debugging

Comment 4 Bug Janitor Service 2024-09-24 03:47:10 UTC

🐛🧹 ⚠️ This bug has been in NEEDSINFO status with no change for at least 15 days. Please provide the requested information, then set the bug status to REPORTED. If there is no change for at least 30 days, it will be automatically closed as RESOLVED WORKSFORME.

For more information about our bug triaging procedures, please read https://community.kde.org/Guidelines_and_HOWTOs/Bug_triaging.

Thank you for helping us make KDE software even better for everyone!

Comment 5 Bug Janitor Service 2024-10-09 03:47:27 UTC

🐛🧹 This bug has been in NEEDSINFO status with no change for at least 30 days. Closing as RESOLVED WORKSFORME.