linux-kernel - Re: [PATCH][v6] PM / hibernate: Print the possible panic reason when resuming with inconsistent e820 map

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Date:   Sun, 28 Aug 2016 14:47:38 +0200
From:   Pavel Machek <pavel@....cz>
To:     Chen Yu <yu.c.chen@...el.com>
Cc:     joeyli <jlee@...e.com>, "Rafael J. Wysocki" <rjw@...ysocki.net>,
        linux-pm@...r.kernel.org, linux-kernel@...r.kernel.org
Subject: Re: [PATCH][v6] PM / hibernate: Print the possible panic reason when
 resuming with inconsistent e820 map

On Sun 2016-08-28 10:07:10, Chen Yu wrote:
> Hi,
> On Fri, Aug 26, 2016 at 09:56:54PM +0200, Pavel Machek wrote:
> > Hi!
> > 
> > > > > > What's the progress of this patch? Looks already have experts review it.
> > > > > > Why this patch didn't accept?
> > > > > This patch is a little overkilled, and I have saved another simpler
> > > > > version to only check the md5 hash (as people suggested) for it. I can post it later.
> > > > > 
> > > > 
> > > > I am happy to test and review it.
> > > >
> > > Here it is. As Rafael is on travel, it would be grateful
> > > if you can give some advance on this, thanks!
> > 
> > Better than last one.
> > 
> > > +		return -ENOMEM;
> > > +
> > > +	req = ahash_request_alloc(tfm, GFP_ATOMIC);
> > 
> > what context is this called from? GFP_ATOMIC allocations like to fail...
> >
> It is in normal process context, OK, I'll change it to GFP_KERNEL.
> > > +static int hibernation_e820_check(void *buf)
> > > +{
> > > +	int ret;
> > > +	char result[MD5_HASH_SIZE] = {0};
> > > +
> > > +	ret = get_e820_md5(&e820_saved, result);
> > > +	if (ret)
> > > +		return ret;
> > > +
> > > +	if (memcmp(result, buf, MD5_HASH_SIZE))
> > > +		e820_conflict = true;
> > 
> > Passing return value using global variable is ugly. Can you just print
> > the warning and kill the box here?
> Do you mean get rid of the panic hooker and just print the warning
> here?

Yep, I'd do that... (And you probably want to rise the severity).

Thanks,
								Pavel
-- 
(english) http://www.livejournal.com/~pavelmachek
(cesky, pictures) http://atrey.karlin.mff.cuni.cz/~pavel/picture/horses/blog.html