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Subject: Re: Question about rtc_lock
From: Thomas Hood <jdthood@mail.com>
Cc: linux-kernel@vger.kernel.org
In-Reply-To: <E15prGs-0001G3-00@the-village.bc.nu>
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Date: 06 Oct 2001 10:40:54 -0400
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On Sat, 2001-10-06 at 09:13, Alan Cox wrote:
> > No, but what if the rtc interrupts while the lock is held in this
> > bit of code?
> 
> Thats fine. It wont take the lock

But the first line of irq_interrupt() is:
   spin_lock (&rtc_lock);

If one has a multi-processor machine, and CPUx is going through
the bootflag code, which takes the rtc_lock, and that CPU is
interrupted and enters rtc_interrupt(), which tries to take the
rtc_lock, won't it deadlock?

If not, then I'm missing some clue about how these spinlocks work.

Thomas

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