linux-kernel - Re: [PATCH RFC 0/2] rtc-cmos: Workaround unwanted interrupt generation

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Message-ID: <20160704161948.GB11075@dhcppc9>
Date:	Mon, 4 Jul 2016 21:49:48 +0530
From:	Pratyush Anand <panand@...hat.com>
To:	mingo@...nel.org, alexandre.belloni@...e-electrons.com,
	Thomas Gleixner <tglx@...utronix.de>
Cc:	rtc-linux@...glegroups.com, linux-kernel@...r.kernel.org,
	prarit@...hat.com
Subject: Re: [PATCH RFC 0/2] rtc-cmos: Workaround unwanted interrupt
 generation

On 27/06/2016:10:19:07 AM, Pratyush Anand wrote:
> On 21/06/2016:10:25:34 AM, Pratyush Anand wrote:
> > We have observed on few machines with rtc-cmos device that
> > hpet_rtc_interrupt() is called before cmos_do_probe() could call
> > hpet_rtc_timer_init(). It has not been observed during normal boot/reboot
> > of machines. It *sometime* happens when system is booted with kdump
> > secondary kernel. So, neither hpet_default_delta nor hpet_t1_cmp is
> > initialized by the time interrupt is raised in the given situation.
> > Therefore while loop of hpet_cnt_ahead() in hpet_rtc_timer_reinit() never
> > completes. This leads to "NMI watchdog: Watchdog detected hard LOCKUP on
> > cpu 0".
> > 
> > I am still clueless, how can an interrupt be raised before RTC is enabled.
> > But i do not have any idea about this device, so I am putting this patch as
> > RFC to get feedback from hpet/rtc-cmos developer. I am sure there would be
> > some better solution than this.
> 
> Do you think that if I improve commit log of patches as pointed by Thomas and
> send a formal version of these patches, then they should acceptable to upstream?

A gentle reminder for your comment/feedback :-)

~Pratyush