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Date:      Mon, 4 Sep 2006 11:16:41 +0200
From:      Stefan Bethke <stb@lassitu.de>
To:        dandee@volny.cz
Cc:        freebsd-stable@freebsd.org
Subject:   Re: watchdogd_flags followed by panic watchdog timeout, after reboot my rc.conf disappear
Message-ID:  <E68F0B99-093D-4116-9915-27903E12C4F3@lassitu.de>
In-Reply-To: <00f701c6ce1a$9d9ea810$6508280a@tocnet28.jspoj.czf>
References:  <00f701c6ce1a$9d9ea810$6508280a@tocnet28.jspoj.czf>

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=1B[ Please do not crosspost. ]

Am 02.09.2006 um 01:01 schrieb Daniel Dvo=C5=99=C3=A1k:

> In the /etc/defaults/rc.conf there are not "watchdogd_flags=3D""" =20
> option, but
> I tried to wrote it to my /etc/rc.conf in this way:
>
> watchdogd_enable=3D"YES"
> watchdogd_flags=3D"-e ping 10.40.0.72 -s 2 -t 1"

You probably would have wanted "-e 'ping 10.40.0.72 -s2 -t1'".  =20
Without the single quotes, the command is just ping, which will exit =20
with 64 (EX_USAGE), so the command never completes successfully, and =20
the kernel watchdog timer is never reset.  Hence the watchdog timeout.

It's a bug in watchdogd that it does not complain about the extra =20
arguments.

> I saved my rc.conf without any doubt.
>
> I did so, because I wanted to instruct watchdogd to execute my =20
> command,
> common pinging some IP address. I was not satisfied with a trivial =20
> file
> system check instead.
>
> After saving the rc.conf file, I restarted watchdogd deamon at once.
>
> ... and ... 2 seconds ... my ssh client was disconnected ... =20
> unexpected end
> of ssh session. :)

Most likely, the rc.conf changes had not been committed to disk when =20
the watchdog timeout occurred, so they got lost.

The watchdog facility is meant to recover the machine from serious =20
problems (like deadlocks, livelocks, or similar).  As such, it will =20
not do a proper shutdown, since the machine is probably in a state =20
where the shutdown would also hang.  It's a last-ditch effort to get =20
the machine to be responsible again, even if there might be damage =20
due to the sudden panic/reboot.

If you want to reboot your router when network connectivity is =20
problematic, I'd set up a cron job to run ping and invoke shutdown -r =20=

if it fails instead.


Stefan

--=20
Stefan Bethke <stb@lassitu.de>   Fon +49 170 346 0140





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