Machine reboots when I log in

[Günter Zöchbauer]

When I come back to my computer

and log in on the dom0 lock screen, the machine often just reboots.

Has anybody seen this?

Any suggestions how to debug?

[Claudia]

You can try journalctl -b -1 -e, but it's probably not syncing the journal before it reboots.

Does it seem to freeze for five seconds before it reboots, or does it reboot immediately?

Does this also happen when you have no VMs running? For me, Xen seems to reboot most often when it's low on memory.

You can try adding noreboot=1 to the Xen command line, and look for any console output when it crashes. If you're up to the task, you could try enabling kernel crash dumps: https://help.ubuntu.com/lts/serverguide/kernel-crash-dump.html

[Günter Zöchbauer]

Thanks for the suggestions.

I'll check journalctl the next time it happens and also pay attention if there is a delay.

I had more than one VM running every time.

Memory in dom0: is currently with a typical workload

KiB Mem :  3943504 total,   569480 free,  2147124 used,  1226900 buff/cache

journalctl shows

balance_when_enough_memory(xen_free_memory=27261583, total_mem_pref=12447403622.400002, total_available_memory=10625527248.599998
left_memory=4055249111 acceptors_count=6

The machine has 32G and it shouldn't use much that yet.

It didn't even look like a crash. It looked like a proper reboot.

I have added noreboot=1 and will report back if I find anything new.

[Günter Zöchbauer]

On Wednesday, February 5, 2020 at 3:32:57 PM UTC+1, Claudia wrote:

You can try adding noreboot=1 to the Xen command line, and look for any console output when it crashes.

Just for others that might stumble upon this thread

The Xen command line is GRUB_CMDLINE_XEN_DEFAULT in /etc/default/grub

and https://groups.google.com/d/msg/qubes-users/uNp2mc3ZZx4/KJ1d_TPZDwAJ explains how to update Grub in Fedora

[Günter Zöchbauer]

This happened a few times within two days but not anymore since.

On Wednesday, February 5, 2020 at 3:32:57 PM UTC+1, Claudia wrote: