From patchwork Sat Aug 19 12:37:07 2017 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Konstantin Khlebnikov X-Patchwork-Id: 803560 X-Patchwork-Delegate: davem@davemloft.net Return-Path: X-Original-To: patchwork-incoming@ozlabs.org Delivered-To: patchwork-incoming@ozlabs.org Authentication-Results: ozlabs.org; spf=none (mailfrom) smtp.mailfrom=vger.kernel.org (client-ip=209.132.180.67; helo=vger.kernel.org; envelope-from=netdev-owner@vger.kernel.org; receiver=) Authentication-Results: ozlabs.org; dkim=pass (1024-bit key; unprotected) header.d=yandex-team.ru header.i=@yandex-team.ru header.b="jMZj9IV+"; dkim-atps=neutral Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by ozlabs.org (Postfix) with ESMTP id 3xZKJw5sMLz9s75 for ; Sat, 19 Aug 2017 22:39:28 +1000 (AEST) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751101AbdHSMhO (ORCPT ); Sat, 19 Aug 2017 08:37:14 -0400 Received: from forwardcorp1j.cmail.yandex.net ([5.255.227.106]:54927 "EHLO forwardcorp1j.cmail.yandex.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751035AbdHSMhO (ORCPT ); Sat, 19 Aug 2017 08:37:14 -0400 Received: from smtpcorp1p.mail.yandex.net (smtpcorp1p.mail.yandex.net [IPv6:2a02:6b8:0:1472:2741:0:8b6:10]) by forwardcorp1j.cmail.yandex.net (Yandex) with ESMTP id 7F77D2069E; Sat, 19 Aug 2017 15:37:11 +0300 (MSK) Received: from smtpcorp1p.mail.yandex.net (localhost.localdomain [127.0.0.1]) by smtpcorp1p.mail.yandex.net (Yandex) with ESMTP id 75BB46E40CD6; Sat, 19 Aug 2017 15:37:11 +0300 (MSK) Received: from unknown (unknown [2a02:6b8:0:6::1:1]) by smtpcorp1p.mail.yandex.net (nwsmtp/Yandex) with ESMTPSA id vZa4CGjFr5-bBUe4aRD; Sat, 19 Aug 2017 15:37:11 +0300 (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (Client certificate not present) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=yandex-team.ru; s=default; t=1503146231; bh=9HCHme7L5ISfu/AGFcbyMBO7pHbmDKkyq96M2wpuDz8=; h=Subject:From:To:Cc:Date:Message-ID; b=jMZj9IV+jd5eTvdMAgrFSf+udAorHnk1e3S8/L3fPYyVzjtw9RAW6uOgBm6mLD7KR 84P0ZTE+fWTRItAdn+fHk7cLDFZ0TQUwkACs5fBLJGhXXnY8w7LXcJ56KDp0fJT0Zz +jDDygcHSyQB93uvZd3qj3lZ0gNV2FJr4NdXQlM0= Authentication-Results: smtpcorp1p.mail.yandex.net; dkim=pass header.i=@yandex-team.ru Subject: [PATCH] net_sched: fix order of queue length updates in qdisc_replace() From: Konstantin Khlebnikov To: netdev@vger.kernel.org, "David S. Miller" Cc: Cong Wang , Jiri Pirko , stable@vger.kernel.org Date: Sat, 19 Aug 2017 15:37:07 +0300 Message-ID: <150314622756.18396.5215271249872220640.stgit@buzz> User-Agent: StGit/0.17.1-dirty MIME-Version: 1.0 Sender: netdev-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: netdev@vger.kernel.org This important to call qdisc_tree_reduce_backlog() after changing queue length. Parent qdisc should deactivate class in ->qlen_notify() called from qdisc_tree_reduce_backlog() but this happens only if qdisc->q.qlen in zero. Missed class deactivations leads to crashes/warnings at picking packets from empty qdisc and corrupting state at reactivating this class in future. Signed-off-by: Konstantin Khlebnikov Fixes: 86a7996cc8a0 ("net_sched: introduce qdisc_replace() helper") Cc: Stable Acked-by: Cong Wang --- include/net/sch_generic.h | 5 ++++- 1 file changed, 4 insertions(+), 1 deletion(-) diff --git a/include/net/sch_generic.h b/include/net/sch_generic.h index 1c123e2b2415..67f815e5d525 100644 --- a/include/net/sch_generic.h +++ b/include/net/sch_generic.h @@ -806,8 +806,11 @@ static inline struct Qdisc *qdisc_replace(struct Qdisc *sch, struct Qdisc *new, old = *pold; *pold = new; if (old != NULL) { - qdisc_tree_reduce_backlog(old, old->q.qlen, old->qstats.backlog); + unsigned int qlen = old->q.qlen; + unsigned int backlog = old->qstats.backlog; + qdisc_reset(old); + qdisc_tree_reduce_backlog(old, qlen, backlog); } sch_tree_unlock(sch);