Re: lockdep and threaded IRQs (was: ...)

From: Ingo Molnar
Date: Mon Mar 02 2009 - 18:58:47 EST



* David Brownell <david-b@xxxxxxxxxxx> wrote:

> On Monday 02 March 2009, Ingo Molnar wrote:
> >
> > > > > What's unfortunate is that you prefer not to fix that
> > > > > IRQF_DISABLED bug in lockdep, which you co-"maintain".
> > > > > When running with lockdep, that bug (a) introduces bugs
> > > > > in some drivers and (b) hides bugs in others.  You've
> > > > > rejected even a minimal warning fix, to help minimize
> > > > > the amount of time developers waste on (a) and (b).
> > > >
> > > > I've come to the conclusion that the only technically sound solution is
> > > > to do as I proposed today, utterly eliminate !IRQF_DISABLED handlers.
> > >
> > > As you announced today.  If you truly believe that, then
> > > you should at least submit a warning patch for 2.6.29-rc
> > > ("driver X isn't setting IRQF_DISABLED, reimplement!")
> >
> > i have changed the BUG_ON() to a WARN_ONCE() message so the
> > warning is in place now.
>
> The patch Peter sent doesn't relate in the least to removing
> the IRQF_DISABLED flag though. Patches addressing that would
> be in setup_irq() code paths not IRQ dispatch.

yes, i referred to the BUG_ON(!irq_irq()) patch.

Ingo
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