From: Oliver Neukum <oliver@neukum.org>
To: Robert Schwebel <robert@schwebel.de>
Subject: Re: [PATCH 2.6.8.1 0/2] leds: new class for led devices
Date: Fri, 3 Sep 2004 10:00:04 +0200
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Cc: John Lenz <lenz@cs.wisc.edu>, linux-kernel@vger.kernel.org
References: <1094157190l.4235l.2l@hydra> <20040903131715.GG1369@pengutronix.de> <20040903133152.GH1369@pengutronix.de>
In-Reply-To: <20040903133152.GH1369@pengutronix.de>
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Am Freitag, 3. September 2004 15:31 schrieb Robert Schwebel:
> On Fri, Sep 03, 2004 at 03:17:15PM +0200, Robert Schwebel wrote:
> > I'll pull the gpio patch out of my working tree and post it here for
> > discussion. 
> 
> Attached. Parts of it have been taken from your LEDs patch anyway, so it
> should be not too difficult to reunify them. 
> 
> Robert
+	list_for_each_safe(lact, ltmp, &gpio_list) {
+		gpio_dev = list_entry(lact, struct gpio_device, list);
+		if (pin_nr == gpio_dev->props.pin_nr) {
+			printk(KERN_ERR "gpio pin %i is already used by %s\n",
+			       pin_nr, gpio_dev->props.owner);
+			return -EBUSY;
+		}
+	}

[..]
+	spin_lock_init(&gpio_dev->lock);
+	gpio_dev->props.pin_nr = pin_nr;

This looks like a race condition. You need to check and reserve under
a lock.

	Regards
		Oliver
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