Can ssh into hanged host, but cannot view systemd status or reboot

Galicarnax · 2021-03-24 06:24:20

Using Arch on two machines, one under i3/X11, another one under sway/Wayland. Sporadically, I encounter a situation where the system freezes - not responsive to keyboard and mouse. I am not sure who is the culprit, since that happens rarely (~ 6-7 times during last year), no clear statistics yet, but it seems it happens at the moment when I exit from the terminal emulator (using kitty). I.e. most of the time when I exit kitty terminals, everything is ok, but one in a hundred or so, it makes the system freeze. It happened on both hosts.

Whoever the culprit, the thing that bugs me most is that I essentially lose control over the host. Switching to virtual console after this happens does not work for some reason. I still can ssh into the host and run 'top'. I then see, e.g., that CPU is loaded 100% with 'sway'. I can kill sway, but nothing happens in the desktop session, it still hangs non-responsive, even in ssh session I see that CPU is no longer loaded 100%. Even more strange, when I ask 'systemctl status', it just hangs without any output. The same if I try 'sudo reboot' - no response. The only thing I can do is to hard-reset the system with the power button...

Since this happens on two independent hosts (desktop and laptop), I wonder if someone else had this experience, and what could be done in this situation to rescue the system without hard-resetting it.

seth · 2021-03-24 07:06:23

https://bbs.archlinux.org/viewtopic.php?id=264844
Harware? Can you check dmesg?

Arch Linux

#1 2021-03-24 06:24:20

Can ssh into hanged host, but cannot view systemd status or reboot

#2 2021-03-24 07:06:23

Re: Can ssh into hanged host, but cannot view systemd status or reboot

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