Bug 417857

Summary:	Intermittent system freezes since 2017 on Kubuntu and Ubuntu on AMD and Intel hardware
Product:	[I don't know] kde	Reporter:	Peter <pemmck>
Component:	general	Assignee:	Unassigned bugs mailing-list <unassigned-bugs>
Status:	RESOLVED UPSTREAM
Severity:	crash
Priority:	NOR
Version:	unspecified
Target Milestone:	---
Platform:	Ubuntu
OS:	Linux
Latest Commit:		Version Fixed In:
Sentry Crash Report:

Description Peter 2020-02-19 02:00:58 UTC

SUMMARY
Total system freezes not dependent on any particular activity. Typically screen remains with a stopped clock and keyboard totally unresponsive. Freezes can happen daily or after longer intervals. I suspected a possible hardware problem BUT freezes do NOT happen if I have desktop effect mouse tracking turned on!

STEPS TO REPRODUCE
1. Boot up Kubuntu
2. No particular activity
3. Freeze will occur during the day. Sometimes longer periods between freezes.

OBSERVED RESULT
System freezes solidly. Keyboard unresponsive regardless of how long I wait.

EXPECTED RESULT
A working system

SOFTWARE/OS VERSIONS
Operating System: Kubuntu 19.10
KDE Plasma Version: 5.18.0
KDE Frameworks Version: 5.67.0
Qt Version: 5.12.4
Kernel Version: 5.3.0-40-generic
OS Type: 64-bit

ADDITIONAL INFORMATION
Current hardware:
Dell inspiron-5674 desktop
Processors: 16 × AMD Ryzen 7 1700X Eight-Core Processor
Memory: 7.7 GiB of RAM
Graphics card: AMD Radeon RX 480

After installing Ubuntu 17.04 on my old ACER i7 laptop in 2017 it started to freeze. I had been running various Linux distros without any problems since 2012! In early 2018 I decided to buy a tower PC, an AMD, details below. To my disgust it too started to freeze intermittently. By freeze I mean the screen was frozen and the keyboard dead. The sort of behaviour you would expect from a hardware problem. No system errors logged!
I am now on Ubuntu and Kubuntu 19.10 and if anything the freezes are worse. BUT, I have discovered a way to prevent the freezes on Kubuntu, a very strange workaround. I found that if I turn mouse tracking on in Kubuntu immediately after logging in I experience NO FREEZES!!! If I forget to do this I am almost certain to experience a freeze during the day. This confirms to me that I have no hardware problem but that some change in Linux between Ubuntu 16.04 and 17.04 created an ongoing problem. My workaround should give the boffins a clue as to how to fix the problem.

There appear to be no relevant logs as system in effect seems to go into a self induced coma.

Comment 1 Christoph Feck 2020-03-06 13:00:46 UTC

KDE software cannot cause the system to freeze. The issue is either in X server or drivers, or even lower (kernel).

Comment 2 Peter 2020-03-06 13:38:27 UTC

(In reply to Christoph Feck from comment #1)
> KDE software cannot cause the system to freeze. The issue is either in X
> server or drivers, or even lower (kernel).

I realise this. The curious part is that a KDE mouse tracking widget can and does prevent the freezes.