RE: [PATCH] gpio: pca953x: Fix dereference of irq data in shutdown

[Mark Walton <mark.walton@xxxxxxxxxxxxx>]

Hi Bart,

> -----Original Message-----
> From: Bartosz Golaszewski <bgolaszewski@xxxxxxxxxxxx>
> Sent: 28 February 2019 13:37
> To: Mark Walton <mark.walton@xxxxxxxxxxxxx>
> Cc: Linus Walleij <linus.walleij@xxxxxxxxxx>; Marek Vasut
> <marek.vasut@xxxxxxxxx>; linux-gpio@xxxxxxxxxxxxxxx
> Subject: Re: [PATCH] gpio: pca953x: Fix dereference of irq data in shutdown
> 
> Hi Mark,
> 
> czw., 28 lut 2019 o 11:45 Mark Walton <mark.walton@xxxxxxxxxxxxx>
> napisał(a):
> >
> > If a PCA953x gpio was used as an interrupt and then released, the
> > shutdown function was trying to extract the pca953x_chip pointer
> > directly from the irq_data, but in reality was getting the gpio_chip
> > structure.
> >
> > The net effect was that the subsequent writes to the data structure
> > corrupted data in the gpio_chip structure, which wasn't immediately
> > obvious until attempting to use the GPIO again in the future, at which
> > point the kernel panics.
> >
> > This fix correctly extracts the pca953x_chip structure via the
> > gpio_chip structure, as is correctly done in the other irq functions.
> >
> > Signed-off-by: Mark Walton <mark.walton@xxxxxxxxxxxxx>
> 
> please add the Fixes: tag - this should go into stable.

OK sure, I'll resubmit this with the Fixes: tag and cc stable.

Mark

> 
> Bart
> 
> > ---
> >  drivers/gpio/gpio-pca953x.c | 3 ++-
> >  1 file changed, 2 insertions(+), 1 deletion(-)
> >
> > diff --git a/drivers/gpio/gpio-pca953x.c b/drivers/gpio/gpio-pca953x.c
> > index caf7dd1..6bd55a4 100644
> > --- a/drivers/gpio/gpio-pca953x.c
> > +++ b/drivers/gpio/gpio-pca953x.c
> > @@ -659,7 +659,8 @@ static int pca953x_irq_set_type(struct irq_data
> > *d, unsigned int type)
> >
> >  static void pca953x_irq_shutdown(struct irq_data *d)  {
> > -       struct pca953x_chip *chip = irq_data_get_irq_chip_data(d);
> > +       struct gpio_chip *gc = irq_data_get_irq_chip_data(d);
> > +       struct pca953x_chip *chip = gpiochip_get_data(gc);
> >         u8 mask = 1 << (d->hwirq % BANK_SZ);
> >
> >         chip->irq_trig_raise[d->hwirq / BANK_SZ] &= ~mask;
> > --
> > 2.7.4
> >