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Date: Sat, 04 Nov 2000 12:07:34 -0500
From: Jeff Garzik <jgarzik@mandrakesoft.com>
Organization: MandrakeSoft
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To: Andi Kleen <ak@suse.de>
CC: "Hen, Shmulik" <shmulik.hen@intel.com>,
        "'LKML'" <linux-kernel@vger.kernel.org>,
        "'LNML'" <linux-net@vger.kernel.org>
Subject: Re: Locking Between User Context and Soft IRQs in 2.4.0
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Andi Kleen wrote:
> All the MOD_INC/DEC_USE_COUNT are done inside the modules themselves. There
> is nothing that would a driver prevent from being unloaded on a different
> CPU while it is already executing in ->open but has not yet executed the add
> yet or after it has executed the _DEC but it is still running in module code
> Normally the windows are pretty small, but very long running interrupt
> on one CPU hitting exactly in the wrong moment can change that.

Module unload calls unregister_netdev, which grabs rtnl_lock.
dev->open runs under rtnl_lock.

Given this, how can the driver be unloaded if dev->open is running?

-- 
Jeff Garzik             | Dinner is ready when
Building 1024           | the smoke alarm goes off.
MandrakeSoft            |	-/usr/games/fortune
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