Thanks. I had hoped for either some correlation with my history.log, or something connected to drawing/rendering the desktop, but nothing jumps out from those, alas. The nvidia/libnvidia-* ones from the 23rd would be the obvious suspect, except you had already posted about the problems (above) when those packages were getting installed.

The apparmor denials for Firefox seem to be a known issue. I don’t use Firefox (and back when I did, I used the Mozilla PPA version instead of the snap), but I suspect they’re not related to the freeze. At least not unless you’re running particularly low on memory.

So we’re running different kernels, even curiouser and curiouser. :)

You’re right that the one you currently have probably has been the only one it’s had since installing (judging from 6.14’s publishing history).

Could you check to see which updates, if any, you’ve installed just prior to the lockups starting? The log files should be under /var/log/apt/ as history.log (the most recent), then history.1.gz (next newest) etc. The .log files are plain text. The .gz ones are compressed, so have to be decompressed first, or, if you’re comfortable with the command line, you can use zless to view them directly.

To me this does look like a kernel issue, but if any non-kernel updates are the trigger, you could perhaps work around the issue by downgrading the package(s), if you can pinpoint which one(s) started the issue.

Right, I’m on (the non-HWE) 6.8 series:

Linux saegusa 6.8.0-90-generic #91-Ubuntu SMP PREEMPT_DYNAMIC Tue Nov 18 14:14:30 UTC 2025 x86_64 x86_64 x86_64 GNU/Linux

According to /var/log/apt/history.log*, I installed it freshly back in December (2025-12-12), and journalctl shows I’d rebooted the next day (the 13th), so have been running it ever since.

Since this is so rare an occurrence on my system, hopefully @anonymousdormouse has the ability to try older/newer kernels with their easily repeatable trigger.

Actually, had this only occurred this week, I might have put my money on it being caused by the “biggest ‘solar radiation storm’ in 23 years”. But, alas, I did have that one incident on the 11th.

Cool, I’m not going crazy! I’ve had a very, very similar issue for a couple of weeks now. Identical in fact, except for the triggers and frequency: three incidents so far, since the first one on January 11th, with the last two within two days earlier this week. In all instances I’ve had Twitch playing video in Librewolf, when suddenly the desktop freezes, leaving only a 500 ms bit of the audio looping endlessly. I had forgotten about magic SysRq, so I have yet to try if it works; I’ve also just done a hard reset instead.

If the logs posted by anonymousdormouse are related to the issue, then that’s one difference wrt. what’s happening here: there’s been nothing related to the problem in any logs. The system seems to just die instantly and completely.

Ubuntu is on an NVMe drive instead of a HDD, and it’s the only OS on the drive.

I have done one pass of memtest to rule out memory errors.

My system doesn’t have Nvidia, it’s using the integrated GPU of a Core i7-8700 with two external displays (one DP-connected, one HDMI-). (This is a Dell XPS desktop that originally came with an external Nvidia GPU, but I ripped it right out before installing the system. I’ve had enough bad experiences with Nvidia to know to avoid them whenever possible.)