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Date: Sun, 9 Jul 2006 09:45:44 +0200
From: Ingo Molnar <mingo@elte.hu>
To: Andrew Morton <akpm@osdl.org>
Cc: Joseph Fannin <jfannin@gmail.com>, linux-kernel@vger.kernel.org,
       arjan@infradead.org, John Stultz <johnstul@us.ibm.com>
Subject: Re: [LOCKDEP] 2.6.18-rc1: inconsistent {hardirq-on-W} -> {in-hardirq-W} usage
Message-ID: <20060709074543.GA4444@elte.hu>
References: <20060709050525.GA1149@nineveh.rivenstone.net> <20060708232512.12b59269.akpm@osdl.org>
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* Andrew Morton <akpm@osdl.org> wrote:

> yup, thanks, bug.
> 
> --- a/arch/i386/kernel/time.c~get_cmos_time-locking-fix
> +++ a/arch/i386/kernel/time.c
> @@ -206,15 +206,16 @@ irqreturn_t timer_interrupt(int irq, voi
>  unsigned long get_cmos_time(void)
>  {
>  	unsigned long retval;
> +	unsigned long flags;
>  
> -	spin_lock(&rtc_lock);
> +	spin_lock_irqsave(&rtc_lock, flags);

Acked-by: Ingo Molnar <mingo@elte.hu>

this bug has been in the upstream kernel for a couple of years: it was
apparently introduced as part of HPET support, via the late_time_init()
hook/hack in init/main.c. The lockup window is open once, during bootup.

	Ingo