linux-kernel - Re: [PATCH] iTCO_wdt: Don't stop on shutdown with nowayout

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-ID: <4B840154.1010501@draigBrady.com>
Date:	Tue, 23 Feb 2010 16:24:52 +0000
From:	Pádraig Brady <P@...igBrady.com>
To:	Simon Kagstrom <simon.kagstrom@...insight.net>
CC:	linux-kernel@...r.kernel.org, wim@...ana.be, seth.heasley@...el.com
Subject: Re: [PATCH] iTCO_wdt: Don't stop on shutdown with nowayout

On 23/02/10 15:40, Simon Kagstrom wrote:
> Currently, the watchdog is turned off when the system shuts down or the
> module is unloaded. If nowayout has been selected, this makes no sense
> and fails to restart the system if it hangs during reboot, so make it
> conditional.
>
> Signed-off-by: Simon Kagstrom<simon.kagstrom@...insight.net>
> ---
> We have a system which has such a hang, and therefore want the watchdog
> to be on until the bitter end.
>
>   drivers/watchdog/iTCO_wdt.c |    3 ++-
>   1 files changed, 2 insertions(+), 1 deletions(-)
>
> diff --git a/drivers/watchdog/iTCO_wdt.c b/drivers/watchdog/iTCO_wdt.c
> index 4bdb7f1..927df26 100644
> --- a/drivers/watchdog/iTCO_wdt.c
> +++ b/drivers/watchdog/iTCO_wdt.c
> @@ -839,7 +839,8 @@ static int __devexit iTCO_wdt_remove(struct platform_device *dev)
>
>   static void iTCO_wdt_shutdown(struct platform_device *dev)
>   {
> -	iTCO_wdt_stop();
> +	if (!nowayout)
> +		iTCO_wdt_stop();
>   }
>
>   #define iTCO_wdt_suspend NULL

I see the issue, however what happens if you're
rebooting into a system that doesn't then renable the watchdog.
I've seen systems where the hardware watchdog is not reset
during the reboot process, in which case you'll get a
reboot while running the other system.

If you had a readonly system, then perhaps you
can just  WDIOC_SETTIMEOUT the hardware watchdog timeout to 1s
and wait for it to reboot the system?

cheers,
Pádraig.
--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@...r.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/