Re: Why can't I set the priority of softirq-hrt? (Re: 2.6.17-rt1)

From: Steven Rostedt
Date: Thu Jun 22 2006 - 09:32:24 EST



On Thu, 22 Jun 2006, Thomas Gleixner wrote:

> On Thu, 2006-06-22 at 00:35 +0100, Esben Nielsen wrote:
> > On Wed, 21 Jun 2006, Thomas Gleixner wrote:
> >
> > > On Wed, 2006-06-21 at 22:29 +0100, Esben Nielsen wrote:
> > >>> Find an version against the code in -mm below. Not too much tested yet.
> > >>
> > >> What if setscheduler is called from interrup context as in the hrt timers?
> > >
> > > It simply gets stuff going, nothing else.
> > >
> > What I mean is that we will then do the full priority inheritance boost
> > with interrupts off.
>
> Only in the case when its called from IRQ context.
>

Uh, Thomas, we can't call rt_mutex_adjust_prio_chain from interrupt
context. It grabs the wait_lock, which is documented not to be
called by interrupts. So this can easily deadlock the system.

-- Steve

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