From mboxrd@z Thu Jan 1 00:00:00 1970 From: David Miller Subject: Re: [PATCH net-next-2.6] ip: ip_ra_control() rcu fix Date: Thu, 10 Jun 2010 22:48:55 -0700 (PDT) Message-ID: <20100610.224855.212696344.davem@davemloft.net> References: <20100607.212612.35795010.davem@davemloft.net> <1276136109.2475.9.camel@edumazet-laptop> <1276136467.2475.13.camel@edumazet-laptop> Mime-Version: 1.0 Content-Type: Text/Plain; charset=us-ascii Content-Transfer-Encoding: 7bit Cc: netdev@vger.kernel.org To: eric.dumazet@gmail.com Return-path: Received: from 74-93-104-97-Washington.hfc.comcastbusiness.net ([74.93.104.97]:52038 "EHLO sunset.davemloft.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751819Ab0FKFso (ORCPT ); Fri, 11 Jun 2010 01:48:44 -0400 In-Reply-To: <1276136467.2475.13.camel@edumazet-laptop> Sender: netdev-owner@vger.kernel.org List-ID: From: Eric Dumazet Date: Thu, 10 Jun 2010 04:21:07 +0200 > [PATCH net-next-2.6 v2] ip: ip_ra_control() rcu fix > > commit 66018506e15b (ip: Router Alert RCU conversion) introduced RCU > lookups to ip_call_ra_chain(). It missed proper deinit phase : > When ip_ra_control() deletes an ip_ra_chain, it should make sure > ip_call_ra_chain() users can not start to use socket during the rcu > grace period. It should also delay the sock_put() after the grace > period, or we risk a premature socket freeing and corruptions, as > raw sockets are not rcu protected yet. > > This delay avoids using expensive atomic_inc_not_zero() in > ip_call_ra_chain(). > > Signed-off-by: Eric Dumazet Applied, thanks Eric.