From patchwork Fri Feb 22 09:44:42 2019 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Li RongQing X-Patchwork-Id: 1046694 X-Patchwork-Delegate: davem@davemloft.net Return-Path: X-Original-To: patchwork-incoming-netdev@ozlabs.org Delivered-To: patchwork-incoming-netdev@ozlabs.org Authentication-Results: ozlabs.org; spf=none (mailfrom) smtp.mailfrom=vger.kernel.org (client-ip=209.132.180.67; helo=vger.kernel.org; envelope-from=netdev-owner@vger.kernel.org; receiver=) Authentication-Results: ozlabs.org; dmarc=none (p=none dis=none) header.from=baidu.com Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by ozlabs.org (Postfix) with ESMTP id 445RJn3PfVz9s71 for ; Fri, 22 Feb 2019 20:44:57 +1100 (AEDT) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726131AbfBVJoz (ORCPT ); Fri, 22 Feb 2019 04:44:55 -0500 Received: from mx133-tc.baidu.com ([61.135.168.133]:13204 "EHLO tc-sys-mailedm06.tc.baidu.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1725836AbfBVJoz (ORCPT ); Fri, 22 Feb 2019 04:44:55 -0500 Received: from localhost (cp01-cos-dev01.cp01.baidu.com [10.92.119.46]) by tc-sys-mailedm06.tc.baidu.com (Postfix) with ESMTP id CDEBD263C017 for ; Fri, 22 Feb 2019 17:44:42 +0800 (CST) From: Li RongQing To: netdev@vger.kernel.org Subject: [PATCH][net-next] ipv6: sanitize RCU usage on fib6_next Date: Fri, 22 Feb 2019 17:44:42 +0800 Message-Id: <1550828682-10608-1-git-send-email-lirongqing@baidu.com> X-Mailer: git-send-email 1.7.1 Sender: netdev-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: netdev@vger.kernel.org using rcu_assign_pointer when setting, which has a memory barrier to ensure the initialization is seen first. using rcu_dereference when dereference this pointer Signed-off-by: Zhang Yu Signed-off-by: Li RongQing --- net/ipv6/ip6_fib.c | 6 ++++-- 1 file changed, 4 insertions(+), 2 deletions(-) diff --git a/net/ipv6/ip6_fib.c b/net/ipv6/ip6_fib.c index 6613d8dbb0e5..b73d40d68178 100644 --- a/net/ipv6/ip6_fib.c +++ b/net/ipv6/ip6_fib.c @@ -1143,7 +1143,7 @@ static int fib6_add_rt2node(struct fib6_node *fn, struct fib6_info *rt, atomic_inc(&rt->fib6_ref); rcu_assign_pointer(rt->fib6_node, fn); - rt->fib6_next = iter->fib6_next; + rcu_assign_pointer(rt->fib6_next, iter->fib6_next); rcu_assign_pointer(*ins, rt); if (!info->skip_notify) inet6_rt_notify(RTM_NEWROUTE, rt, info, NLM_F_REPLACE); @@ -1761,7 +1761,9 @@ static void fib6_del_route(struct fib6_table *table, struct fib6_node *fn, RT6_TRACE("fib6_del_route\n"); /* Unlink it */ - *rtp = rt->fib6_next; + *rtp = rcu_dereference_protected(rt->fib6_next, + lockdep_is_held(&rt->fib6_table->tb6_lock)); + rt->fib6_node = NULL; net->ipv6.rt6_stats->fib_rt_entries--; net->ipv6.rt6_stats->fib_discarded_routes++;