linux-kernel - Re: [2.6.25-rc1] System no longer powers off after shutdown

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Message-ID: <20080213165837.GA10129@suse.de>
Date:	Wed, 13 Feb 2008 08:58:37 -0800
From:	Greg KH <gregkh@...e.de>
To:	Frans Pop <elendil@...net.nl>
Cc:	linux-kernel@...r.kernel.org, linux-acpi@...r.kernel.org
Subject: Re: [2.6.25-rc1] System no longer powers off after shutdown

On Wed, Feb 13, 2008 at 12:39:13PM +0100, Frans Pop wrote:
> On Tuesday 12 February 2008, Greg KH wrote:
> > On Tue, Feb 12, 2008 at 09:39:14PM +0100, Frans Pop wrote:
> > > On Monday 11 February 2008, Frans Pop wrote:
> > > > In general 2.6.25 if looking quite good on my desktop, but there's
> > > > one important issue: the system no longer powers off after shutdown.
> > > > This works fine with 2.6.24.
> > >
> > > Don't ask me why, but bisection shows this commit to be the cause of
> > > the failure to power off:
> > > commit c10997f6575f476ff38442fa18fd4a0d80345f9d
> > > Author: Greg Kroah-Hartman <gregkh@...e.de>
> > > Date:   Thu Dec 20 08:13:05 2007 -0800
> > >
> > >     Kobject: convert drivers/* from kobject_unregister() to
> > > kobject_put()
> > >
> > > Because it seemed somewhat unlikely, I have double checked this by
> > > doing an extra compilation for this commit and its predecessor.
> >
> > What is the symptom of not powering off?
> 
> I already noticed yesterday that there's one hunk in that commit that's not
> a straight replacement:
> diff --git a/drivers/cpufreq/cpufreq.c b/drivers/cpufreq/cpufreq.c
> index 9e102af..5efd555 100644
> --- a/drivers/cpufreq/cpufreq.c
> +++ b/drivers/cpufreq/cpufreq.c
> @@ -1030,8 +1030,6 @@ static int __cpufreq_remove_dev (struct sys_device * sys_dev)
> 
>         unlock_policy_rwsem_write(cpu);
> 
> -       kobject_unregister(&data->kobj);
> -
>         kobject_put(&data->kobj);
> 
>         /* we need to make sure that the underlying kobj is actually
> 
> 
> So, just on the off chance, I applied the patch below and bingo, the system
> powers off again. I doubt this will be the correct solution, but just in
> case it is, here's my signed off. A comment why the double put is needed
> would probably be good though.

There is a bug in the cpufreq kref logic that makes this "double put"
necessary.  A real fix has already been posted to solve this issue, and
I think it should be on it's way to Linus for -rc2 already.

Please let me know if -rc2 comes out without this needed fix.

thanks,

greg k-h
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