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From:   Keith Owens <kaos@ocs.com.au>
To:     Andrew Morton <andrewm@uow.edu.au>
cc:     "netdev@oss.sgi.com" <netdev@oss.sgi.com>
Subject: Re: modular net drivers 
In-reply-to: Your message of "Mon, 19 Jun 2000 23:54:30 +1000."
             <394E2616.C25F8376@uow.edu.au> 
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Date:   Tue, 20 Jun 2000 01:20:41 +1000
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On Mon, 19 Jun 2000 23:54:30 +1000, 
Andrew Morton <andrewm@uow.edu.au> wrote:
>--- linux-2.4.0-test1-ac21/net/core/dev.c	Mon Jun 19 16:47:54 2000
>+++ linux-akpm/net/core/dev.c	Mon Jun 19 21:28:14 2000
>@@ -664,8 +665,13 @@
> 	 *	Call device private open method
> 	 */
> 	 
>-	if (dev->open) 
>+	if (dev->open) {
>+		if (dev->owner)
>+			__MOD_INC_USE_COUNT(dev->owner);
>   		ret = dev->open(dev);
>+		if (ret != 0 && dev->owner)
>+			__MOD_DEC_USE_COUNT(dev->owner);
>+	}

Racy.  The module referred to by dev->owner might be in the middle of
being unloaded.  You need try_inc_mod_count() with a check on its
result instead of __MOD_INC_USE_COUNT.