linux-kernel - Re: [PATCH] PM / Hibernation: Fix *massive* memory leak at early exits in hibernation

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Date:	Tue, 22 Nov 2011 21:33:13 +0100
From:	"Rafael J. Wysocki" <rjw@...k.pl>
To:	Pavel Machek <pavel@....cz>
Cc:	"Srivatsa S. Bhat" <srivatsa.bhat@...ux.vnet.ibm.com>,
	len.brown@...el.com, tj@...nel.org, linux-kernel@...r.kernel.org,
	linux-pm@...r.kernel.org
Subject: Re: [PATCH] PM / Hibernation: Fix *massive* memory leak at early exits in hibernation

On Tuesday, November 22, 2011, Pavel Machek wrote:
> On Mon 2011-11-21 23:25:39, Rafael J. Wysocki wrote:
> > On Monday, November 21, 2011, Srivatsa S. Bhat wrote:
> > > At some of the early exit points during hibernation (exiting either due
> > > to failure or after a successful hibernation test, the memory pre-allocated
> > > for hibernation is not freed up. And this is *very* serious, because, during
> > > pre-allocation, it could have allocated upto a few *gigabytes* of memory!
> > > And hence, if a hibernation fails or even if we run some hibernation tests
> > > using the 'pm_test' framework, the system is rendered unstable due to memory
> > > becoming signifantly lower. Fix this bug.
> > 
> > While the observation is valid, I'd prefer to do something like the patch
> > below.
> 
> The code slowly becomes goto maze :-(.
> 
> > @@ -357,12 +357,14 @@ int hibernation_snapshot(int platform_mo
> >  		 * successful freezer test.
> >  		 */
> >  		freezer_test_done = true;
> > -		goto Close;
> > +		goto Cleanup;
> >  	}
> >  
> >  	error = dpm_prepare(PMSG_FREEZE);
> > -	if (error)
> > -		goto Complete_devices;
> > +	if (error) {
> > +		dpm_complete(msg);
> > +		goto Cleanup;
> > +	}
> 
> Perhaps dpm_prepare should be changed to clean after itself in the
> error case? That is the normal convention AFAICT....

Yes, in a future patch.

Thanks,
Rafael
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