On 28-12-16, 22:56, David Gstir wrote:
> Since migrating to the 'set-state' interface the cs5535 driver causes a
> crash after loading: Right after initialization, the IRQ handler
> (mfgpt_tick) is triggered with clock event device in detached state. This
> state not properly handled and causes a crash through NULL pointer
> dereference upon calling the clockevent's event_handler.
>
> This patch fixes this by handling the detached state the same way the
> shutdown state is handled.
>
> Fixes: 8f9327cbb6e8 ("clockevents/drivers/cs5535: Migrate to new 'set-state' interface")
> Cc: stable@xxxxxxxxxxxxxxx
> Cc: Andres Salomon <dilinger@xxxxxxxxxx>
> Cc: Viresh Kumar <viresh.kumar@xxxxxxxxxx>
> Signed-off-by: David Gstir <david@xxxxxxxxxxxxx>
> ---
> drivers/clocksource/cs5535-clockevt.c | 3 ++-
> 1 file changed, 2 insertions(+), 1 deletion(-)
>
> diff --git a/drivers/clocksource/cs5535-clockevt.c b/drivers/clocksource/cs5535-clockevt.c
> index 9a7e37cf56b0..649e0cd90805 100644
> --- a/drivers/clocksource/cs5535-clockevt.c
> +++ b/drivers/clocksource/cs5535-clockevt.c
> @@ -117,7 +117,8 @@ static irqreturn_t mfgpt_tick(int irq, void *dev_id)
> /* Turn off the clock (and clear the event) */
> disable_timer(cs5535_event_clock);
>
> - if (clockevent_state_shutdown(&cs5535_clockevent))
> + if (clockevent_state_shutdown(&cs5535_clockevent) ||
> + clockevent_state_detached(&cs5535_clockevent))
> return IRQ_HANDLED;
>
> /* Clear the counter */
Sorry for breaking it, but it looks we have unearthed a bug because of
my patch.
I wouldn't enable the IRQ unless the clockevents core has asked for
it, i.e. by calling set_state_periodic() or set_state_oneshot().
The driver is currently enabling the IRQ from its init code and that's
where the problem is IMHO.
--
viresh
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