linux-kernel - Re: w83697hf_wdt.c stops watchdog on load

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: <47D7C464.7060909@draigBrady.com>
Date:	Wed, 12 Mar 2008 11:54:12 +0000
From:	Pádraig Brady <P@...igBrady.com>
To:	Samuel Tardieu <sam@...1149.net>
CC:	Wim Van Sebroeck <wim@...ana.be>, junker@...uras.de,
	LKML <linux-kernel@...r.kernel.org>
Subject: Re: w83697hf_wdt.c stops watchdog on load

Samuel Tardieu wrote:
> On 11/03, Wim Van Sebroeck wrote:
> 
> | > > Isn't it a two-edged sword?
> | > 
> | > True, but one should be able to set things up so that there is no race.
> | > I.E. if you add the autodisable, it should only be done as an option.
> | > Best have it =no by default, but as least one could turn this off.
> | 
> | In my opinion it should be the other way around: the default behaviour is to
> | stop the watchdog and to let userspace (the watchdog-daemon) control the
> | watchdog. So if we add a module parameter to take over the watchdog's
> | bios-setting, then the default behaviour should be to stop the watchdog and
> | add an option that takes the value from the bios.
> 
> Hi Wim.
> 
> That was my intent: disable the watchdog by default

When doing this it would be useful to print a warning iif the watchdog was running.
I.E. the following would be possible for the w83697:

init() {
  if (watchdog_already_running) {
     printk("warning, stopping watchdog. Use the nodisable option to keep running");
     disable_watchdog();
  }
}

See the w83627 driver for how to determine watchdog is running.

>, and add an option
> not to disable it (let it untouched, so getting the BIOS setting) at
> module initialization, as Pádraig request is totally reasonable.

cool, thanks.

Pádraig.

p.s. I'm still not sure it should default to turning off.
It would be unusual for userspace to take over 60s to _start_
If that was the case then the user shouldn't enable the watchdog in the BIOS at all.
--
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/