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 A4A66C55186 for ; Thu, 23 Apr 2020 23:12:03 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 85D3320784 for ; Thu, 23 Apr 2020 23:12:03 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728940AbgDWXMC (ORCPT ); Thu, 23 Apr 2020 19:12:02 -0400 Received: from shadbolt.e.decadent.org.uk ([88.96.1.126]:50160 "EHLO shadbolt.e.decadent.org.uk" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1728531AbgDWXGv (ORCPT ); Thu, 23 Apr 2020 19:06:51 -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 1jRkvX-0004lg-Nm; Fri, 24 Apr 2020 00:06:39 +0100 Received: from ben by deadeye with local (Exim 4.93) (envelope-from ) id 1jRkvT-00E6tc-Ou; Fri, 24 Apr 2020 00:06:35 +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 , "Eric Dumazet" , "David S. Miller" , "Kenneth Klette Jonassen" Date: Fri, 24 Apr 2020 00:06:29 +0100 Message-ID: X-Mailer: LinuxStableQueue (scripts by bwh) X-Patchwork-Hint: ignore Subject: [PATCH 3.16 162/245] pkt_sched: fq: avoid hang when quantum 0 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 3.16.83-rc1 review patch. If anyone has any objections, please let me know. ------------------ From: Kenneth Klette Jonassen commit 3725a269815ba6dbb415feddc47da5af7d1fac58 upstream. Configuring fq with quantum 0 hangs the system, presumably because of a non-interruptible infinite loop. Either way quantum 0 does not make sense. Reproduce with: sudo tc qdisc add dev lo root fq quantum 0 initial_quantum 0 ping 127.0.0.1 Signed-off-by: Kenneth Klette Jonassen Acked-by: Eric Dumazet Signed-off-by: David S. Miller Signed-off-by: Ben Hutchings --- net/sched/sch_fq.c | 10 ++++++++-- 1 file changed, 8 insertions(+), 2 deletions(-) --- a/net/sched/sch_fq.c +++ b/net/sched/sch_fq.c @@ -687,8 +687,14 @@ static int fq_change(struct Qdisc *sch, if (tb[TCA_FQ_FLOW_PLIMIT]) q->flow_plimit = nla_get_u32(tb[TCA_FQ_FLOW_PLIMIT]); - if (tb[TCA_FQ_QUANTUM]) - q->quantum = nla_get_u32(tb[TCA_FQ_QUANTUM]); + if (tb[TCA_FQ_QUANTUM]) { + u32 quantum = nla_get_u32(tb[TCA_FQ_QUANTUM]); + + if (quantum > 0) + q->quantum = quantum; + else + err = -EINVAL; + } if (tb[TCA_FQ_INITIAL_QUANTUM]) q->initial_quantum = nla_get_u32(tb[TCA_FQ_INITIAL_QUANTUM]);