From: Hans Ulli Kroll <ulli.kroll@googlemail.com>
To: Thomas Gleixner <tglx@linutronix.de>
Cc: Hans Ulli Kroll <ulli.kroll@googlemail.com>,
linux-kernel@vger.kernel.org,
Daniel Lezcano <daniel.lezcano@linaro.org>,
stable@vger.kernel.org
Subject: Re: [PATCH] clocksource:fix kernel panic due missing event_handler in cs5535
Date: Tue, 31 May 2016 09:09:29 +0200 (CEST) [thread overview]
Message-ID: <alpine.LNX.2.00.1605310904450.26919@T520.work> (raw)
In-Reply-To: <alpine.DEB.2.11.1605301234310.3639@nanos>
HI
On Mon, 30 May 2016, Thomas Gleixner wrote:
> On Mon, 30 May 2016, Hans Ulli Kroll wrote:
>
> > Missing event_handler in mfgpt_tick() caused a kernel panic.
>
> So the real problem is that the interrupt in the device is enabled _BEFORE_
> the clock event device is registered.
>
> > diff --git a/drivers/clocksource/cs5535-clockevt.c b/drivers/clocksource/cs5535-clockevt.c
> > index 9a7e37c..6f186cf 100644
> > --- a/drivers/clocksource/cs5535-clockevt.c
> > +++ b/drivers/clocksource/cs5535-clockevt.c
> > @@ -129,7 +129,9 @@ static irqreturn_t mfgpt_tick(int irq, void *dev_id)
> > cs5535_mfgpt_write(cs5535_event_clock, MFGPT_REG_SETUP,
> > MFGPT_SETUP_CNTEN | MFGPT_SETUP_CMP2);
> >
> > - cs5535_clockevent.event_handler(&cs5535_clockevent);
> > + if (cs5535_clockevent.event_handler)
> > + cs5535_clockevent.event_handler(&cs5535_clockevent);
> > +
>
> So what about fixing the above problem instead of having a conditional in the
> interrupt handler fast path?
>
So there in an default handler for this in the clockevent framework.
OK, for this approach.
I'll send another patch.
Greetings from Cologne
Hans Ulli Kroll
prev parent reply other threads:[~2016-05-31 7:09 UTC|newest]
Thread overview: 2+ messages / expand[flat|nested] mbox.gz Atom feed top
[not found] <1464604292-11276-1-git-send-email-ulli.kroll@googlemail.com>
2016-05-30 10:35 ` [PATCH] clocksource:fix kernel panic due missing event_handler in cs5535 Thomas Gleixner
2016-05-31 7:09 ` Hans Ulli Kroll [this message]
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