Re: [PATCH] clockevents/drivers/timer-atmel-pit: fix double free_irq

From: Nicolas Ferre
Date: Fri Mar 18 2016 - 04:20:27 EST


Le 17/03/2016 21:09, Alexandre Belloni a écrit :
> clockevents_exchange_device() changes the state from detached to shutdown
> and so at that point the IRQ has not yet been requested.
>
> Signed-off-by: Alexandre Belloni <alexandre.belloni@xxxxxxxxxxxxxxxxxx>

Acked-by: Nicolas Ferre <nicolas.ferre@xxxxxxxxx>

> ---
>
> Hi Sebastian,
>
> This patch fixes the last warning for preempt-rt on at91. It applies on
> v4.4.4-rt11. Note that the whome PIT/TCB mess will be fixed in another way in
> the mainline as we are reworking the tcb driver to avoid using the pit when
> booting.

Yes, it's the plan!

Thanks Alexandre. Bye.

>
> drivers/clocksource/timer-atmel-pit.c | 8 +++++++-
> 1 file changed, 7 insertions(+), 1 deletion(-)
>
> diff --git a/drivers/clocksource/timer-atmel-pit.c b/drivers/clocksource/timer-atmel-pit.c
> index a7abdb6638cd..7a40f7e88468 100644
> --- a/drivers/clocksource/timer-atmel-pit.c
> +++ b/drivers/clocksource/timer-atmel-pit.c
> @@ -46,6 +46,7 @@ struct pit_data {
> u32 cycle;
> u32 cnt;
> unsigned int irq;
> + bool irq_requested;
> struct clk *mck;
> };
>
> @@ -96,7 +97,10 @@ static int pit_clkevt_shutdown(struct clock_event_device *dev)
>
> /* disable irq, leaving the clocksource active */
> pit_write(data->base, AT91_PIT_MR, (data->cycle - 1) | AT91_PIT_PITEN);
> - free_irq(data->irq, data);
> + if (data->irq_requested) {
> + free_irq(data->irq, data);
> + data->irq_requested = false;
> + }
> return 0;
> }
>
> @@ -115,6 +119,8 @@ static int pit_clkevt_set_periodic(struct clock_event_device *dev)
> if (ret)
> panic(pr_fmt("Unable to setup IRQ\n"));
>
> + data->irq_requested = true;
> +
> /* update clocksource counter */
> data->cnt += data->cycle * PIT_PICNT(pit_read(data->base, AT91_PIT_PIVR));
> pit_write(data->base, AT91_PIT_MR,
>


--
Nicolas Ferre