On 10/29/2017 12:56 PM, Johan Hovold wrote: > Take an extra reference to the controller to avoid use-after-free in > free_irq() which is called only after the controller has been > deregistered and freed. > > Note that this is not an issue for this particular driver which does not > use shared interrupts, but free_irq() could otherwise end up accessing > the freed controller when CONFIG_DEBUG_SHIRQ is set.
Strictly speaking there is no guarantee that the IRQ handler does not run until free_irq() has been called. And since the SPI master is referenced in the IRQ handler there could be an use-after-free condition. So there is kind of a real issue here as well. But it should be really really hard to trigger it unless the hardware misbehaves. > > Defer controller release until free_irq() returns to prevent this > from ever becoming an issue should this code be replicated in other > drivers. > > Cc: Lars-Peter Clausen <l...@metafoo.de> > Signed-off-by: Johan Hovold <jo...@kernel.org> Acked-by: Lars-Peter Clausen <l...@metafoo.de> Thanks.
