Re: [PATCH 1/4] cgroup freezer: Fix buggy resume test for tasks frozen with cgroup freezer

["Serge E. Hallyn" <serue-r/Jw6+rmf7HQT0dZR+AlfA@public.gmane.org>]

Quoting Matt Helsley (matthltc-r/Jw6+rmf7HQT0dZR+AlfA@public.gmane.org):
> -int cgroup_frozen(struct task_struct *task)
> +int cgroup_freezing_or_frozen(struct task_struct *task)
>  {
>  	struct freezer *freezer;
>  	enum freezer_state state;
> 
>  	task_lock(task);
>  	freezer = task_freezer(task);
> -	state = freezer->state;
> +	if (!freezer->css.cgroup->parent)
> +		state = CGROUP_THAWED; /* root cgroup can't be frozen */
> +	else
> +		state = freezer->state;

Why do you have to add this special-casing now?  I thought
we were already preventing freezing the root cgroup, so
freezer->state should be sane in that case anyway?

>  	task_unlock(task);
> 
> -	return state == CGROUP_FROZEN;
> +	return (state == CGROUP_FREEZING) || (state == CGROUP_FROZEN);
>  }

-serge