From mboxrd@z Thu Jan 1 00:00:00 1970 From: Jarek Poplawski Subject: Re: [PATCH] locking bug in fib_semantics.c Date: Mon, 21 Aug 2006 13:02:01 +0200 Message-ID: <20060821110201.GA3674@ff.dom.local> References: <20060817093615.GA25553@ms2.inr.ac.ru> <20060821081642.GA2637@ff.dom.local> <20060821.011703.78716718.davem@davemloft.net> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Cc: netdev@vger.kernel.org Return-path: Received: from mx2.go2.pl ([193.17.41.42]:59297 "EHLO poczta.o2.pl") by vger.kernel.org with ESMTP id S1751855AbWHUK7E (ORCPT ); Mon, 21 Aug 2006 06:59:04 -0400 To: David Miller Content-Disposition: inline In-Reply-To: <20060821.011703.78716718.davem@davemloft.net> Sender: netdev-owner@vger.kernel.org List-Id: netdev.vger.kernel.org On 21-08-2006 10:17, David Miller wrote: > From: Jarek Poplawski > Date: Mon, 21 Aug 2006 10:16:43 +0200 ... >> But I hope the real reason for this patch isn't exactly like that. >> Could fib_release_info() be interrupted by BH really? > > Absolutely, yes it can. What makes you think it can't? > > All of the call sites I have checked cause it to run with > BH's enabled, and that allows ip_fib_check_default() to > potentially run. All we need is one such case to cause > the deadlock. > > I was skeptical of this case too, until I checked how > fib_release_info() was called. I overlooked this - so I've to sharpen my sight and look at it again - now knowing it's there. Thanks for your response. I didn't expect it so fast and right from the top! Jarek P.