From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-3.8 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED autolearn=no autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 271D2C32751 for ; Sat, 10 Aug 2019 20:46:50 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 0538A208C3 for ; Sat, 10 Aug 2019 20:46:50 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727361AbfHJUqs (ORCPT ); Sat, 10 Aug 2019 16:46:48 -0400 Received: from shadbolt.e.decadent.org.uk ([88.96.1.126]:55298 "EHLO shadbolt.e.decadent.org.uk" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726896AbfHJUoH (ORCPT ); Sat, 10 Aug 2019 16:44:07 -0400 Received: from [192.168.4.242] (helo=deadeye) by shadbolt.decadent.org.uk with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.89) (envelope-from ) id 1hwYDb-00053O-W2; Sat, 10 Aug 2019 21:44:04 +0100 Received: from ben by deadeye with local (Exim 4.92) (envelope-from ) id 1hwYDL-0003dn-HG; Sat, 10 Aug 2019 21:43:47 +0100 Content-Type: text/plain; charset="UTF-8" Content-Disposition: inline Content-Transfer-Encoding: 8bit MIME-Version: 1.0 From: Ben Hutchings To: linux-kernel@vger.kernel.org, stable@vger.kernel.org CC: akpm@linux-foundation.org, Denis Kirjanov , "Nikolay Aleksandrov" , "David S. Miller" Date: Sat, 10 Aug 2019 21:40:07 +0100 Message-ID: X-Mailer: LinuxStableQueue (scripts by bwh) X-Patchwork-Hint: ignore Subject: [PATCH 3.16 079/157] net: bridge: multicast: use rcu to access port list from br_multicast_start_querier In-Reply-To: X-SA-Exim-Connect-IP: 192.168.4.242 X-SA-Exim-Mail-From: ben@decadent.org.uk X-SA-Exim-Scanned: No (on shadbolt.decadent.org.uk); SAEximRunCond expanded to false Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 3.16.72-rc1 review patch. If anyone has any objections, please let me know. ------------------ From: Nikolay Aleksandrov commit c5b493ce192bd7a4e7bd073b5685aad121eeef82 upstream. br_multicast_start_querier() walks over the port list but it can be called from a timer with only multicast_lock held which doesn't protect the port list, so use RCU to walk over it. Fixes: c83b8fab06fc ("bridge: Restart queries when last querier expires") Signed-off-by: Nikolay Aleksandrov Signed-off-by: David S. Miller Signed-off-by: Ben Hutchings --- net/bridge/br_multicast.c | 4 +++- 1 file changed, 3 insertions(+), 1 deletion(-) --- a/net/bridge/br_multicast.c +++ b/net/bridge/br_multicast.c @@ -2036,7 +2036,8 @@ static void br_multicast_start_querier(s __br_multicast_open(br, query); - list_for_each_entry(port, &br->port_list, list) { + rcu_read_lock(); + list_for_each_entry_rcu(port, &br->port_list, list) { if (port->state == BR_STATE_DISABLED || port->state == BR_STATE_BLOCKING) continue; @@ -2048,6 +2049,7 @@ static void br_multicast_start_querier(s br_multicast_enable(&port->ip6_own_query); #endif } + rcu_read_unlock(); } int br_multicast_toggle(struct net_bridge *br, unsigned long val)