Re: [PATCH] sched: don't take a mutex from interrupt context

[Peter Zijlstra <a.p.zijlstra@chello.nl>]

On Tue, 2008-01-22 at 22:21 +0530, Srivatsa Vaddagiri wrote:
> On Tue, Jan 22, 2008 at 05:25:38PM +0100, Peter Zijlstra wrote:
> > @@ -1428,9 +1428,9 @@ static void print_cfs_stats(struct seq_f
> >  #ifdef CONFIG_FAIR_GROUP_SCHED
> >  	print_cfs_rq(m, cpu, &cpu_rq(cpu)->cfs);
> >  #endif
> > -	lock_task_group_list();
> > +	rcu_read_lock();
> >  	for_each_leaf_cfs_rq(cpu_rq(cpu), cfs_rq)
> >  		print_cfs_rq(m, cpu, cfs_rq);
> 
> Isn't there a possibility that print_cfs_rq() can block?

It should not, that would be another bug, but from a quick glance at the
code it doesn't do that.

> 
> > -	unlock_task_group_list();
> > +	rcu_read_unlock();
> >  }
> >  #endif
> > 
>