Re: [PATCH v2] iio: adc: exynos: do not rely on 'users' counter in ISR
On Tue, Oct 06, 2020 at 09:39:07PM +0200, Michał Mirosław wrote:
> On Mon, Oct 05, 2020 at 09:12:14PM -0700, dmitry.torok...@gmail.com wrote:
> > The order in which 'users' counter is decremented vs calling drivers'
> > close() method is implementation specific, and we should not rely on
> > it. Let's introduce driver private flag and use it to signal ISR
> > to exit when device is being closed.
> >
> > This has a side-effect of fixing issue of accessing inut->users
> > outside of input->mutex protection.
> [...]
>
> Reviewed-by: Michał Mirosław
> (after with a fix mentioned below)
>
> > --- a/drivers/iio/adc/exynos_adc.c
> > +++ b/drivers/iio/adc/exynos_adc.c
> [...]
> > @@ -712,6 +715,7 @@ static int exynos_adc_ts_open(struct input_dev *dev)
> > {
> > struct exynos_adc *info = input_get_drvdata(dev);
> >
> > + WRITE_ONCE(info->ts_enabled, true);
> > enable_irq(info->tsirq);
> >
> > return 0;
> > @@ -721,6 +725,7 @@ static void exynos_adc_ts_close(struct input_dev *dev)
> > {
> > struct exynos_adc *info = input_get_drvdata(dev);
> >
> > + WRITE_ONCE(info->ts_enabled, true);
> > disable_irq(info->tsirq);
>
> Shouldn't 'true' be 'false' here?
I swear if we disable cut-n-paste functionality there will be markable
reduction in bug rates...
Thanks for noticing this!
--
Dmitry
Re: [PATCH v2] iio: adc: exynos: do not rely on 'users' counter in ISR
On Mon, Oct 05, 2020 at 09:12:14PM -0700, dmitry.torok...@gmail.com wrote:
> The order in which 'users' counter is decremented vs calling drivers'
> close() method is implementation specific, and we should not rely on
> it. Let's introduce driver private flag and use it to signal ISR
> to exit when device is being closed.
>
> This has a side-effect of fixing issue of accessing inut->users
> outside of input->mutex protection.
[...]
Reviewed-by: Michał Mirosław
(after with a fix mentioned below)
> --- a/drivers/iio/adc/exynos_adc.c
> +++ b/drivers/iio/adc/exynos_adc.c
[...]
> @@ -712,6 +715,7 @@ static int exynos_adc_ts_open(struct input_dev *dev)
> {
> struct exynos_adc *info = input_get_drvdata(dev);
>
> + WRITE_ONCE(info->ts_enabled, true);
> enable_irq(info->tsirq);
>
> return 0;
> @@ -721,6 +725,7 @@ static void exynos_adc_ts_close(struct input_dev *dev)
> {
> struct exynos_adc *info = input_get_drvdata(dev);
>
> + WRITE_ONCE(info->ts_enabled, true);
> disable_irq(info->tsirq);
Shouldn't 'true' be 'false' here?
Best Regards,
Michał Mirosław
Re: [PATCH v2] iio: adc: exynos: do not rely on 'users' counter in ISR
On Tue, 6 Oct 2020 at 06:12, wrote: > > The order in which 'users' counter is decremented vs calling drivers' > close() method is implementation specific, and we should not rely on > it. Let's introduce driver private flag and use it to signal ISR > to exit when device is being closed. > > This has a side-effect of fixing issue of accessing inut->users > outside of input->mutex protection. > > Reported-by: Andrzej Pietrasiewicz > Signed-off-by: Dmitry Torokhov > --- > > v2: switched from ordinary read/write to READ_ONCE/WRITE_ONCE per Michał > Mirosław > > drivers/iio/adc/exynos_adc.c | 7 ++- > 1 file changed, 6 insertions(+), 1 deletion(-) Acked-by: Krzysztof Kozlowski Best regards, Krzysztof
