From mboxrd@z Thu Jan  1 00:00:00 1970
From: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
Subject: Re: 2.6.39 crashes BUG: unable to handle kernel NULL pointer
 dereference at 000000000000042 .. cmos_checkintr+0x4d/0x55 under Xen as PV
 guest.
Date: Tue, 22 Mar 2011 10:38:41 -0400
Message-ID: <20110322143841.GA26952@dumpdata.com>
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To: John Stultz <john.stultz@linaro.org>
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> > No. 2.6.38 vaniall works great.
> 
> Ok. Hrm. 
> 
> > > Any insight there?
> > 
> > I hoped you might have :-)
> 
> Could you help me understand where in the probe logic xen bombs out of
> the cmos code?

Sure. The issue is that rtc_update_irq calls schedule_work with rtc->irqwork
which has not been initialized. The reason for that is that rtc_device_register
has never been called.. uh wait, that does not make sense, it is called in
cmos_do_probe. Hmm, let get find out exactly on which variable queue_work_on
bombs out on.