From patchwork Wed Jul 15 09:09:59 2015 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Luis Henriques X-Patchwork-Id: 495578 Return-Path: X-Original-To: incoming@patchwork.ozlabs.org Delivered-To: patchwork-incoming@bilbo.ozlabs.org Received: from huckleberry.canonical.com (huckleberry.canonical.com [91.189.94.19]) by ozlabs.org (Postfix) with ESMTP id D33181402BD; Wed, 15 Jul 2015 19:15:57 +1000 (AEST) Received: from localhost ([127.0.0.1] helo=huckleberry.canonical.com) by huckleberry.canonical.com with esmtp (Exim 4.76) (envelope-from ) id 1ZFInB-0007na-30; Wed, 15 Jul 2015 09:15:53 +0000 Received: from youngberry.canonical.com ([91.189.89.112]) by huckleberry.canonical.com with esmtp (Exim 4.76) (envelope-from ) id 1ZFIkY-0005Qw-DC for kernel-team@lists.ubuntu.com; Wed, 15 Jul 2015 09:13:10 +0000 Received: from av-217-129-142-138.netvisao.pt ([217.129.142.138] helo=localhost) by youngberry.canonical.com with esmtpsa (TLS1.0:RSA_AES_128_CBC_SHA1:16) (Exim 4.76) (envelope-from ) id 1ZFIkX-0007I0-2c; Wed, 15 Jul 2015 09:13:09 +0000 From: Luis Henriques To: linux-kernel@vger.kernel.org, stable@vger.kernel.org, kernel-team@lists.ubuntu.com Subject: [PATCH 3.16.y-ckt 004/185] bridge: fix multicast router rlist endless loop Date: Wed, 15 Jul 2015 10:09:59 +0100 Message-Id: <1436951580-15977-5-git-send-email-luis.henriques@canonical.com> X-Mailer: git-send-email 2.1.4 In-Reply-To: <1436951580-15977-1-git-send-email-luis.henriques@canonical.com> References: <1436951580-15977-1-git-send-email-luis.henriques@canonical.com> X-Extended-Stable: 3.16 Cc: Nikolay Aleksandrov , "David S. Miller" X-BeenThere: kernel-team@lists.ubuntu.com X-Mailman-Version: 2.1.14 Precedence: list List-Id: Kernel team discussions List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , MIME-Version: 1.0 Errors-To: kernel-team-bounces@lists.ubuntu.com Sender: kernel-team-bounces@lists.ubuntu.com 3.16.7-ckt15 -stable review patch. If anyone has any objections, please let me know. ------------------ From: Nikolay Aleksandrov commit 1a040eaca1a22f8da8285ceda6b5e4a2cb704867 upstream. Since the addition of sysfs multicast router support if one set multicast_router to "2" more than once, then the port would be added to the hlist every time and could end up linking to itself and thus causing an endless loop for rlist walkers. So to reproduce just do: echo 2 > multicast_router; echo 2 > multicast_router; in a bridge port and let some igmp traffic flow, for me it hangs up in br_multicast_flood(). Fix this by adding a check in br_multicast_add_router() if the port is already linked. The reason this didn't happen before the addition of multicast_router sysfs entries is because there's a !hlist_unhashed check that prevents it. Signed-off-by: Nikolay Aleksandrov Fixes: 0909e11758bd ("bridge: Add multicast_router sysfs entries") Acked-by: Herbert Xu Signed-off-by: David S. Miller Signed-off-by: Luis Henriques --- net/bridge/br_multicast.c | 7 +++---- 1 file changed, 3 insertions(+), 4 deletions(-) diff --git a/net/bridge/br_multicast.c b/net/bridge/br_multicast.c index 799379e81264..32de99bf6e42 100644 --- a/net/bridge/br_multicast.c +++ b/net/bridge/br_multicast.c @@ -1166,6 +1166,9 @@ static void br_multicast_add_router(struct net_bridge *br, struct net_bridge_port *p; struct hlist_node *slot = NULL; + if (!hlist_unhashed(&port->rlist)) + return; + hlist_for_each_entry(p, &br->router_list, rlist) { if ((unsigned long) port >= (unsigned long) p) break; @@ -1193,12 +1196,8 @@ static void br_multicast_mark_router(struct net_bridge *br, if (port->multicast_router != 1) return; - if (!hlist_unhashed(&port->rlist)) - goto timer; - br_multicast_add_router(br, port); -timer: mod_timer(&port->multicast_router_timer, now + br->multicast_querier_interval); }