Bug 511227 - Plasma 6.5 using X11 - ASSERT: “m_cache.isEmpty()” in file ./src/scene/workspacescene_opengl.cpp, line 125
Summary: Plasma 6.5 using X11 - ASSERT: “m_cache.isEmpty()” in file ./src/scene/worksp...
Status: RESOLVED UPSTREAM
Alias: None
Product: kwin
Classification: Plasma
Component: generic-crash (other bugs)
Version First Reported In: 6.5.0
Platform: Kubuntu Linux
: NOR crash
Target Milestone: ---
Assignee: KWin default assignee
URL:
Keywords:
Depends on:
Blocks:
 
Reported: 2025-10-27 17:20 UTC by Wade
Modified: 2025-10-27 17:23 UTC (History)
1 user (show)

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


Attachments
Journal log containing crash information (148.04 KB, text/x-log)
2025-10-27 17:20 UTC, Wade
Details

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Description Wade 2025-10-27 17:20:03 UTC
Created attachment 186236 [details]
Journal log containing crash information

I originally posted a question on discuss.kde.org as an occasional deadlock in Plasma 6.  The discussion can be found at the following URL:

https://discuss.kde.org/t/occasional-deadlock-in-plasma-6/40922

The problem occurs randomly with a frequency of a few days to a week between instances, and requires a machine reboot to recover, as the UI is non-responsive.  I have not found a way to reproduce it on demand.

With the help of a KDE developer, I was able to collect journal information that shows that the problem is due to the assertion in the summary.  I have attached the journal log.

I attempted to collect a coredump file, but this crash does not appear to generate a dump.


SOFTWARE/OS VERSIONS
Operating System: Kubuntu 24.04
KDE Plasma Version: 6.5.0
KDE Frameworks Version: 6.19.0
Qt Version: 6.9.2
Kernel Version: 6.8.0-86-generic (64-bit)
Graphics Platform: X11
Processors: 32 × Intel® Core™ i9-14900KF
Memory: 128 GiB of RAM (125.6 GiB usable)
Graphics Processor: NVIDIA GeForce RTX 3060
Manufacturer: Gigabyte Technology Co., Ltd.
Product Name: Z790 AORUS ELITE X WIFI7
System Version: -CF
Comment 1 David Edmundson 2025-10-27 17:23:50 UTC
Oct 03 04:18:51 fly-by-night kwin_x11[2253]: The X11 connection broke: I/O error (code 1)

Oct 03 04:18:51 fly-by-night kwin_x11[2253]: ASSERT: "m_cache.isEmpty()" in file ./src/scene/workspacescene_opengl.cpp, line 125

The X11 server is crashing. 
Please look at your logs for Xserver and report there.

Kwin is asserting on the way out, but by that point it's already too late.