Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754381Ab2JGXWx (ORCPT ); Sun, 7 Oct 2012 19:22:53 -0400 Received: from shadbolt.e.decadent.org.uk ([88.96.1.126]:38348 "EHLO shadbolt.e.decadent.org.uk" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752881Ab2JGXW2 (ORCPT ); Sun, 7 Oct 2012 19:22:28 -0400 Message-Id: <20121007225846.722454035@decadent.org.uk> User-Agent: quilt/0.60-1 Date: Mon, 08 Oct 2012 00:00:01 +0100 From: Ben Hutchings To: linux-kernel@vger.kernel.org, stable@vger.kernel.org Cc: akpm@linux-foundation.org, alan@lxorguk.ukuu.org.uk, Eric Dumazet , Denys Fedoryschenko , "David S. Miller" Subject: [ 087/108] net-sched: sch_cbq: avoid infinite loop In-Reply-To: <20121007225834.673681075@decadent.org.uk> X-SA-Exim-Connect-IP: 2001:470:1f08:1539:21c:bfff:fe03:f805 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 List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1782 Lines: 56 3.2-stable review patch. If anyone has any objections, please let me know. ------------------ From: Eric Dumazet [ Upstream commit bdfc87f7d1e253e0a61e2fc6a75ea9d76f7fc03a ] Its possible to setup a bad cbq configuration leading to an infinite loop in cbq_classify() DEV_OUT=eth0 ICMP="match ip protocol 1 0xff" U32="protocol ip u32" DST="match ip dst" tc qdisc add dev $DEV_OUT root handle 1: cbq avpkt 1000 \ bandwidth 100mbit tc class add dev $DEV_OUT parent 1: classid 1:1 cbq \ rate 512kbit allot 1500 prio 5 bounded isolated tc filter add dev $DEV_OUT parent 1: prio 3 $U32 \ $ICMP $DST 192.168.3.234 flowid 1: Reported-by: Denys Fedoryschenko Tested-by: Denys Fedoryschenko Signed-off-by: Eric Dumazet Signed-off-by: David S. Miller Signed-off-by: Ben Hutchings --- net/sched/sch_cbq.c | 5 +++-- 1 file changed, 3 insertions(+), 2 deletions(-) diff --git a/net/sched/sch_cbq.c b/net/sched/sch_cbq.c index 24d94c0..599f67a 100644 --- a/net/sched/sch_cbq.c +++ b/net/sched/sch_cbq.c @@ -250,10 +250,11 @@ cbq_classify(struct sk_buff *skb, struct Qdisc *sch, int *qerr) else if ((cl = defmap[res.classid & TC_PRIO_MAX]) == NULL) cl = defmap[TC_PRIO_BESTEFFORT]; - if (cl == NULL || cl->level >= head->level) + if (cl == NULL) goto fallback; } - + if (cl->level >= head->level) + goto fallback; #ifdef CONFIG_NET_CLS_ACT switch (result) { case TC_ACT_QUEUED: -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/