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=-6.8 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS autolearn=ham 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 A448EC3A5A1 for ; Wed, 28 Aug 2019 16:31:06 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 81B6C20644 for ; Wed, 28 Aug 2019 16:31:06 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726515AbfH1QbF (ORCPT ); Wed, 28 Aug 2019 12:31:05 -0400 Received: from mga01.intel.com ([192.55.52.88]:7940 "EHLO mga01.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726472AbfH1QbF (ORCPT ); Wed, 28 Aug 2019 12:31:05 -0400 X-Amp-Result: SKIPPED(no attachment in message) X-Amp-File-Uploaded: False Received: from fmsmga006.fm.intel.com ([10.253.24.20]) by fmsmga101.fm.intel.com with ESMTP/TLS/DHE-RSA-AES256-GCM-SHA384; 28 Aug 2019 09:31:05 -0700 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.64,441,1559545200"; d="scan'208";a="381336519" Received: from unknown (HELO ellie) ([10.24.12.211]) by fmsmga006.fm.intel.com with ESMTP; 28 Aug 2019 09:31:04 -0700 From: Vinicius Costa Gomes To: Vladimir Oltean , jhs@mojatatu.com, xiyou.wangcong@gmail.com, jiri@resnulli.us, davem@davemloft.net, vedang.patel@intel.com, leandro.maciel.dorileo@intel.com Cc: netdev@vger.kernel.org, Vladimir Oltean Subject: Re: [PATCH net 1/3] taprio: Fix kernel panic in taprio_destroy In-Reply-To: <20190828144829.32570-2-olteanv@gmail.com> References: <20190828144829.32570-1-olteanv@gmail.com> <20190828144829.32570-2-olteanv@gmail.com> Date: Wed, 28 Aug 2019 09:31:04 -0700 Message-ID: <87a7btqmk7.fsf@intel.com> MIME-Version: 1.0 Content-Type: text/plain Sender: netdev-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: netdev@vger.kernel.org Hi, Vladimir Oltean writes: > taprio_init may fail earlier than this line: > > list_add(&q->taprio_list, &taprio_list); > > i.e. due to the net device not being multi queue. Good catch. > > Attempting to remove q from the global taprio_list when it is not part > of it will result in a kernel panic. > > Fix it by iterating through the list and removing it only if found. > > Signed-off-by: Vladimir Oltean > --- > net/sched/sch_taprio.c | 9 +++++++-- > 1 file changed, 7 insertions(+), 2 deletions(-) > > diff --git a/net/sched/sch_taprio.c b/net/sched/sch_taprio.c > index 540bde009ea5..f1eea8c68011 100644 > --- a/net/sched/sch_taprio.c > +++ b/net/sched/sch_taprio.c > @@ -1199,12 +1199,17 @@ static int taprio_change(struct Qdisc *sch, struct nlattr *opt, > > static void taprio_destroy(struct Qdisc *sch) > { > - struct taprio_sched *q = qdisc_priv(sch); > + struct taprio_sched *p, *q = qdisc_priv(sch); > struct net_device *dev = qdisc_dev(sch); > + struct list_head *pos, *tmp; > unsigned int i; > > spin_lock(&taprio_list_lock); > - list_del(&q->taprio_list); > + list_for_each_safe(pos, tmp, &taprio_list) { > + p = list_entry(pos, struct taprio_sched, taprio_list); > + if (p == q) > + list_del(&q->taprio_list); > + } Personally, I would do things differently, I am thinking: adding the taprio instance earlier to the list in taprio_init(), and keeping taprio_destroy() the way it is now. But take this more as a suggestion :-) Cheers, -- Vinicius