Re: Re: [PATCH] gpio: gpiolib-of: Fix refcount bugs in of_mm_gpiochip_add_data()

[Andy Shevchenko <andy.shevchenko@xxxxxxxxx>]

On Wed, Jul 6, 2022 at 3:49 AM Liang He <windhl@xxxxxxx> wrote:
> At 2022-07-05 23:40:12, "Bartosz Golaszewski" <brgl@xxxxxxxx> wrote:
> >On Mon, Jul 4, 2022 at 11:13 AM Liang He <windhl@xxxxxxx> wrote:

...

> This patch is based on the fact that there is a call site in function 'qe_add_gpiochips()'
> of src file 'drivers\soc\fsl\qe\gpio.c'.
>
> In that function, of_mm_gpiochip_add_data() is contained in a iteration of for_each_compatible_node(),
> which will automatically increase and decrease the refcount.

"and decrease"


> As there is a new reference escaped into the mm_gc->gc.of_node, we should increase the
> refcount, otherwise, there may be a premature free as we do not know the existence of
> the reference in 'mm_gc->gc.of_node'.
>
> If my understanding is wrong, please correct me.

Yes, see above.

-- 
With Best Regards,
Andy Shevchenko