Re: [patch 2/3] rtmutex: Propagate priority settings into PI lock chains

[Andrew Morton <akpm@osdl.org>]

On Thu, 22 Jun 2006 10:20:59 -0400 (EDT)
Steven Rostedt <rostedt@goodmis.org> wrote:

> > +	if (!waiter || waiter->list_entry.prio == task->prio) {
> > +		spin_unlock_irqrestore(&task->pi_lock, flags);
> > +		return;
> > +	}
> > +
> > +	/* gets dropped in rt_mutex_adjust_prio_chain()! */
> > +	get_task_struct(task);
> > +	spin_unlock_irqrestore(&task->pi_lock, flags);
> > +
> > +	rt_mutex_adjust_prio_chain(task, 0, NULL, NULL, task);
> 
> The above means that you cant ever call sched_setscheduler from a
> interrupt handler (or softirq).  The rt_mutex_adjust_prio_chain since that
> grabs wait_lock which is not for interrupt use.

Running setscheduler() from IRQ context sounds rather perverse. 
BUG_ON(in_interrupt()) would reduce the temptation.