Re: [PATCH -tip] irq: check chip->ack before calling (WAS: irq:remove unneeded desc->chip->ack check)

[Ingo Molnar]

* Wang Chen <wangchen@xxxxxxxxxxxxxx> wrote:

> Ingo Molnar said the following on 2008-12-26 21:27:
> > * Wang Chen <wangchen@xxxxxxxxxxxxxx> wrote:
> > 
> >> desc->chip->ack is initialized to ack_bad().
> >> It will not be NULL.
> > 
> > hm, that is only true of no_irq_chip() - is it true of all irq_chip 
> > definitions on all architectures?
> > 
> 
> No, some arch's irq_chip doesn't have ack routine.
> So I was wrong.
> But this enlighten another thought that generic irq layer doesn't know
> whether irq_chip has ack routine on some architectures.
> Upon that, before calling chip->ack, should check it's not NULL.
> 
> Impact: fix theoretic NULL dereference
> 
> Signed-off-by: Wang Chen <wangchen@xxxxxxxxxxxxxx>

applied to tip/irq/genirq, thanks!

(find below how the final commit message ended up looking like.)

	Ingo

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