[systemd-devel] Watchdog problem

[Chuck Wolber]

On Sat, Sep 7, 2019 at 06:12 Mikael Djurfeldt <mikael at djurfeldt.com> wrote:

>
%< Snip %<

>
> When the host has gone to sleep and wakes up again, I get logged out from
> my gdm session. It starts out like this:
>
> Sep  7 13:23:58 hat kernel: [82210.177399] 11:23:58.337557 timesync
> vgsvcTimeSyncWorker: Radical guest time change: 2 491 379 233 000ns
> (GuestNow=1 567 855 438 281 378 000 ns GuestLast=1 567 852 946 902 145 000
> ns fSetTimeLastLoop=false)
> Sep  7 13:23:59 hat systemd[1]: systemd-logind.service: Watchdog timeout
> (limit 3min)!
> Sep  7 13:23:59 hat /usr/lib/gdm3/gdm-x-session[1285]: (EE)
> Sep  7 13:23:59 hat /usr/lib/gdm3/gdm-x-session[1285]: Fatal server error:
> Sep  7 13:23:59 hat /usr/lib/gdm3/gdm-x-session[1285]: (EE) systemd-logind
> disappeared (stopped/restarted?)
>
> Can I fix this by setting systemd-logind.service WatchdogSec to something
> else? What should I set it to to disable watchdogs? I tried to find
> documentation for WatchdogSec but failed. Can you please point me to the
> proper documentation?
>

Without looking at the code, it seems as if the watchdog is using clock
deltas, rather than checking kernel ticks (or its own internal tick
accumulator). If that is correct, I wonder if there is a reason for doing
it that way. Jumps in system time will cause havoc with anything that
operates that way.

In any case, you can get rid of the watchdog altogether with an override.
Granted, you will not detect logind hangs, but that is probably not a huge
concern for your particular use case if you want to stay logged in all the
time.

..Ch:W..

> --
“I would challenge anyone here to think of a question upon which we once
had a scientific answer, however inadequate, but for which now the best
answer is a religious one."  -Sam Harris
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <https://lists.freedesktop.org/archives/systemd-devel/attachments/20190907/79786612/attachment.html>