On Thu, 23 Apr 2020 03:53:07 -0700 ToddAndMargo via users users@lists.fedoraproject.org wrote:
Randomly and not associated with any particular program, my system will slow down. It becomes obvious when I can type faster than letters appear. And when this happens, a reboot will fix it.
As Roger said, this is probably a resource issue. Something is hogging the CPU or memory, and limiting the time slice for your typing interrupts. The keystroke logger on your system is misbehaving. Or maybe it is the bitcoin miner causing the problem. We'll send out new ones as soon as possible. ;-)
But the shutdown and reboot process hangs when the slowdown appears. After the shutdown/reboot sequence gets to "Target Reached Power Off" (or restart), a delay of about two minutes and then I get my CPU registries displayed over and over.
This is because a running application didn't respond to a kill -15 signal. In that case, systemd waits for a default 90 seconds before sending a kill -9. This can be changed by changing DefaultTimeoutStopSec in /etc/systemd/system.conf However, it is good to have a noticeable timeout because it brings to your attention issues like this.
Looks like this: repeating CPU registries: https://bugzilla.redhat.com/attachment.cgi?id=1672106
This is my dmesg: # journalctl -b --no-hostname -k > dmesg.tx https://bugzilla.redhat.com/attachment.cgi?id=1672107
This looks like a denial of service attack. Something is not taking no for an answer. It keeps sending invalid packets to the kernel. No wonder your responsiveness gets so bad.
This has happened three times in one day. It has also gone for days without an issue.
And again, no particular program either. I initially thought it was qemu-kvm, then VLC, but it has happened with neither running. And just sitting at the desktop with the screen saver running.
Any words of wisdom?
You should start shutting down by doing shutdown -P now in a virtual console (e.g. Ctrl-Alt-F2). Then, systemd will tell you why it is pausing before sending the kill -9 whenever it happens. Unfortunately, you have little recourse once the freeze happens, thus you are just waiting to trap the issue, and will usually shutdown without it happening.