Re: [PATCH 1/7] clocksource: mediatek: Don't run event_handler if it is NULL

[Daniel Lezcano]

On 05/04/2015 10:34 AM, Matthias Brugger wrote:
> 2015-05-04 10:14 GMT+02:00 Daniel Lezcano <daniel.lezcano@xxxxxxxxxx>:
> > On 05/01/2015 09:43 AM, Yingjoe Chen wrote:
> > > Spurious timer interrupt is noticed in mtk timer and cause kernel
> > > crash. In mtk_timer_interrupt(), only run event_handler if it is
> > > not NULL.
> > >
> > > Signed-off-by: Yingjoe Chen <yingjoe.chen@xxxxxxxxxxxx>
> > > ---
> > >    drivers/clocksource/mtk_timer.c | 3 ++-
> > >    1 file changed, 2 insertions(+), 1 deletion(-)
> > >
> > > diff --git a/drivers/clocksource/mtk_timer.c
> > > b/drivers/clocksource/mtk_timer.c
> > > index 68ab423..85e0ab5 100644
> > > --- a/drivers/clocksource/mtk_timer.c
> > > +++ b/drivers/clocksource/mtk_timer.c
> > > @@ -143,7 +143,8 @@ static irqreturn_t mtk_timer_interrupt(int irq, void
> > > *dev_id)
> > >
> > >          /* Acknowledge timer0 irq */
> > >          writel(GPT_IRQ_ACK(GPT_CLK_EVT), evt->gpt_base + GPT_IRQ_ACK_REG);
> > > -       evt->dev.event_handler(&evt->dev);
> > > +       if (evt->dev.event_handler)
> > > +               evt->dev.event_handler(&evt->dev);
> > >
> > >          return IRQ_HANDLED;
> > >    }
> >
> > This fix does not look good.
> >
> > Could you try by requesting the irq *after* clockevents_config_and_register
> > in the init sequence [1] ?
>
>  From my understanding [1] should already fix this.
>
> [1] https://git.kernel.org/cgit/linux/kernel/git/stable/linux-stable.git/commit/drivers/clocksource/mtk_timer.c?id=d4a19eb3b15a4ba98f627182f48d5bc0cffae670

Indeed it seems to fix it. But I think request_irq should be done after 
clockevents_config_and_register in any case.

Yingjoe, are the spurious interrupts occurring with the fix Matthias 
mentions ?


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