Re: [PATCH 1/2] irq_flags_t: intro and core annotations

[Jeff Garzik]

Herbert Xu wrote:
> Jeff Garzik <jeff@xxxxxxxxxx> wrote:
> > Let me add to the chorus of voices:  I continually see two cases where 
> > real bugs crop up:
> >
> > 1) hacker uses spin_lock_irq() in incorrect context (where it is not 
> > safe to do a blind enable/disable)
> >
> > 2) hacker uses spin_lock_irq() correctly, but the surrounding code 
> > changes, thus invalidating prior assumptions.
> >
> > I would even go so far as to support the drastic measure of deleting 
> > spin_lock_irq().
> >
> > spin_lock_irqsave() generates fewer bugs, is more future-proof, and by 
> > virtue of 'flags' permits architectures a bit more flexibility.
>
> Could we add a debug option that warned if spin_lock_irq is
> executed with IRQs turned off already?

Seems reasonable but perhaps arch-specific?

Also, I think someone (akpm?) mentioned an effort had been made before, 
and run into some problems.  I don't have details...

	Jeff



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