Hi!

> Fix the problem with kthread_stop() that causes the freezer to fail if a
> freezable thread is attempting to stop a frozen one and that may cause the
> freezer to fail if the thread being stopped is freezable and
> try_to_freeze_tasks() is running concurrently with kthread_stop().

Parse error.

> Index: linux-2.6.21-rc6-mm1/kernel/kthread.c
> ===================================================================
> --- linux-2.6.21-rc6-mm1.orig/kernel/kthread.c        2007-04-09 
> 15:23:48.000000000 +0200
> +++ linux-2.6.21-rc6-mm1/kernel/kthread.c     2007-04-22 19:05:29.000000000 
> +0200
> @@ -232,6 +233,14 @@ int kthread_stop(struct task_struct *k)
>  
>       /* Now set kthread_should_stop() to true, and wake it up. */
>       kthread_stop_info.k = k;
> +     if (!freezer_should_exempt(current)) {
> +             /* We are freezable, so we must make sure that the thread being
> +              * stopped is not frozen and will not be frozen until it dies
> +              */
> +             freezer_exempt(k);
> +             if (frozen(k))
> +                     clear_frozen_flag(k);
> +     }
>       wake_up_process(k);
>       put_task_struct(k);
>  

Do we need to take some locks to access other process' flags? Or do
frozen_exempt() etc take enough locks, already?
                                                                        Pavel
-- 
(english) http://www.livejournal.com/~pavelmachek
(cesky, pictures) 
http://atrey.karlin.mff.cuni.cz/~pavel/picture/horses/blog.html
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