Re: [PATCH 1/1] gpio: omap: Fix bad device access with setup_irq()

[Russell King - ARM Linux <linux@xxxxxxxxxxxxxxxx>]

On Fri, Jan 16, 2015 at 04:19:41PM -0800, santosh shilimkar wrote:
> On 1/16/2015 2:50 PM, Tony Lindgren wrote:
> >Similar to omap_gpio_irq_type() let's make sure that the GPIO
> >is usable as an interrupt if the platform init code did not
> >call gpio_request(). Otherwise we can get invalid device access
> >after setup_irq():
> >
> I let Linus W comment on it but IIRC we chewed this issue last
> time and the conclusion was the gpio_request() must have to be called
> directly or indirectly in case of irq line.

That's really not the issue here.

The issue is that it's possible to claim the interrupt, and then the
driver goes wrong - not only does it attempt in that case to access
hardware which is runtime suspended, if the interrupt is subsequently
freed, it will then do a pm_runtime_put().

The interrupt code is wrong there, plain and simple.

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