From mboxrd@z Thu Jan 1 00:00:00 1970 From: Patrick McHardy Subject: Re: mmotm 2010-04-28 - RCU whinges Date: Mon, 10 May 2010 18:03:05 +0200 Message-ID: <4BE82E39.6080603@trash.net> References: <1272865137.2173.179.camel@edumazet-laptop> <1272865267.2173.180.camel@edumazet-laptop> <1272865436.2173.182.camel@edumazet-laptop> <20100502.225509.233880079.davem@davemloft.net> <4BE8290A.2080707@trash.net> <1273506968.2221.19.camel@edumazet-laptop> Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-15 Content-Transfer-Encoding: QUOTED-PRINTABLE Cc: David Miller , Valdis.Kletnieks@vt.edu, akpm@linux-foundation.org, peterz@infradead.org, linux-kernel@vger.kernel.org, netfilter-devel@vger.kernel.org, netdev@vger.kernel.org, paulmck@linux.vnet.ibm.com To: Eric Dumazet Return-path: Received: from stinky.trash.net ([213.144.137.162]:49135 "EHLO stinky.trash.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754016Ab0EJQDI (ORCPT ); Mon, 10 May 2010 12:03:08 -0400 In-Reply-To: <1273506968.2221.19.camel@edumazet-laptop> Sender: netfilter-devel-owner@vger.kernel.org List-ID: Eric Dumazet wrote: > Le lundi 10 mai 2010 =E0 17:40 +0200, Patrick McHardy a =E9crit : >> David Miller wrote: >>> From: Eric Dumazet >>> Date: Mon, 03 May 2010 07:43:56 +0200 >>> >>>> Le lundi 03 mai 2010 =E0 07:41 +0200, Eric Dumazet a =E9crit : >>>> >>>>> Oops scratch that, I'll resend a correct version. >>>>> >>>>> >>>> Sorry, patch _is_ fine, I had one brain collapse when re-reading i= t, I >>>> thought a different mutex was in use in one of the functions. >>> Ok, Patrick please review, thanks. >> Actually we don't need the rcu_dereference() calls at all since >> registration and unregistration are protected by the mutexes. >> >> I queued this patch in nf-next, the only reason why I haven't >> submitted it yet is that I was unable to get git to cleanly export >> only the proper set of patches meant for -next due to a few merges, >> it insists on including 5 patches already merged upstream. If you >> don't mind ignoring the first 5 patches in the series, I'll send a >> pull request tonight. >> >=20 > This will clash with upcoming RCU patches, where rcu protected pointe= r > cannot be directly accessed without lockdep splats. >=20 > We will need one day or another a rcu_...(nf_conntrack_event_cb) Thanks for the information, I didn't realize that when looking at those patches. So I guess the correct fix once those patches are merged would be to use rcu_assign_protected() and rcu_access_pointer(). -- To unsubscribe from this list: send the line "unsubscribe netfilter-dev= el" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html