linux-kernel - Re: [PATCH v2 10/11] watchdog/hpwdt: remove allow

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Date:   Tue, 13 Feb 2018 16:10:51 -0700
From:   Jerry Hoemann <jerry.hoemann@....com>
To:     Guenter Roeck <linux@...ck-us.net>
Cc:     wim@...ux-watchdog.org, linux-watchdog@...r.kernel.org,
        linux-kernel@...r.kernel.org, rwright@....com,
        maurice.a.saldivar@....com
Subject: Re: [PATCH v2 10/11] watchdog/hpwdt: remove allow_kdump module
 parameter.

On Tue, Feb 13, 2018 at 10:20:42AM -0800, Guenter Roeck wrote:
> On Sun, Feb 11, 2018 at 10:21:10PM -0700, Jerry Hoemann wrote:
> > The intent of this parameter is unclear and it sets up a
> > race between the reset of the system by ASR and crashdump.
> > 
> > The length of time between receipt of the pretimeout NMI
> > and the ASR reset of the system is fixed by hardware.
> > 
> > Turning the parameter off doesn't necessairly prevent a crash dump.
> > Also, having the ASR reset occur while the system is crash dumping
> > doesn't imply that the dump was hung given the short duration
> > between the NMI and the reset.
> > 
> > This parameter is not a substitute for having a architected watchdog
> > crashdump hang detection paridigm.
> > 
> > Signed-off-by: Jerry Hoemann <jerry.hoemann@....com>
> > ---
> >  drivers/watchdog/hpwdt.c | 7 +------
> >  1 file changed, 1 insertion(+), 6 deletions(-)
> > 
> > diff --git a/drivers/watchdog/hpwdt.c b/drivers/watchdog/hpwdt.c
> > index e9e54fe20804..bb0dcc8709b8 100644
> > --- a/drivers/watchdog/hpwdt.c
> > +++ b/drivers/watchdog/hpwdt.c
> > @@ -33,7 +33,6 @@
> >  static unsigned int soft_margin = DEFAULT_MARGIN;	/* in seconds */
> >  static bool nowayout = WATCHDOG_NOWAYOUT;
> >  #ifdef CONFIG_HPWDT_NMI_DECODING
> > -static unsigned int allow_kdump = 1;
> 
> At the end of hpwdt_init_nmi_decoding(), there used to be a log message
> showing the value of allow_kdump. Maybe that was removed in another patch,
> but it really belongs to this patch, or am I missing something ?
> 
> Guenter

That got pulled into patch 6.  I'll refactor the patches to include the
message change here.



-- 

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Jerry Hoemann                  Software Engineer   Hewlett Packard Enterprise
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