From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-wm0-f67.google.com ([74.125.82.67]:33831 "EHLO mail-wm0-f67.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751283AbcEaHJl (ORCPT ); Tue, 31 May 2016 03:09:41 -0400 Date: Tue, 31 May 2016 09:09:29 +0200 (CEST) From: Hans Ulli Kroll To: Thomas Gleixner cc: Hans Ulli Kroll , linux-kernel@vger.kernel.org, Daniel Lezcano , stable@vger.kernel.org Subject: Re: [PATCH] clocksource:fix kernel panic due missing event_handler in cs5535 In-Reply-To: Message-ID: References: <1464604292-11276-1-git-send-email-ulli.kroll@googlemail.com> MIME-Version: 1.0 Content-Type: TEXT/PLAIN; charset=US-ASCII Sender: stable-owner@vger.kernel.org List-ID: 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