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Subject: Re: [PATCH] powerpc: remove useless spinlock from mpc83xx watchdog
From: Alan Cox <alan@lxorguk.ukuu.org.uk>
To: Marcelo Tosatti <marcelo.tosatti@cyclades.com>
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Date: Thu, 19 Jan 2006 22:12:19 +0000
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Cc: Andrew Morton <akpm@osdl.org>, Kumar Gala <galak@gate.crashing.org>,
	wim@iguana.be, linux-kernel@vger.kernel.org, linuxppc-embedded@ozlabs.org
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On Iau, 2006-01-19 at 14:48 -0200, Marcelo Tosatti wrote:
> On Thu, Jan 19, 2006 at 09:49:16AM +0000, Alan Cox wrote:
> > 
> > 	f = open("/dev/watchdog", O_RDWR);
> > 	fork();
> > 	while(1) {
> > 		write(f, "Boing", 5);
> > 	}
> 
> Oops.
> 
> At least 50% of the watchdog drivers rely solely on the "wdt_is_open"
> atomic variable and are broken with respect to synchronization.

What an excellent janitors project