From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail.linuxfoundation.org ([140.211.169.12]:46480 "EHLO mail.linuxfoundation.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754333AbdHYAp5 (ORCPT ); Thu, 24 Aug 2017 20:45:57 -0400 Subject: Patch "net_sched: fix order of queue length updates in qdisc_replace()" has been added to the 4.12-stable tree To: khlebnikov@yandex-team.ru, davem@davemloft.net, gregkh@linuxfoundation.org, xiyou.wangcong@gmail.com Cc: , From: Date: Thu, 24 Aug 2017 17:44:43 -0700 Message-ID: <1503621883212180@kroah.com> MIME-Version: 1.0 Content-Type: text/plain; charset=ANSI_X3.4-1968 Content-Transfer-Encoding: 8bit Sender: stable-owner@vger.kernel.org List-ID: This is a note to let you know that I've just added the patch titled net_sched: fix order of queue length updates in qdisc_replace() to the 4.12-stable tree which can be found at: http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary The filename of the patch is: net_sched-fix-order-of-queue-length-updates-in-qdisc_replace.patch and it can be found in the queue-4.12 subdirectory. If you, or anyone else, feels it should not be added to the stable tree, please let know about it. >>From foo@baz Thu Aug 24 17:43:45 PDT 2017 From: Konstantin Khlebnikov Date: Sat, 19 Aug 2017 15:37:07 +0300 Subject: net_sched: fix order of queue length updates in qdisc_replace() From: Konstantin Khlebnikov [ Upstream commit 68a66d149a8c78ec6720f268597302883e48e9fa ] 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") Acked-by: Cong Wang Signed-off-by: David S. Miller Signed-off-by: Greg Kroah-Hartman --- include/net/sch_generic.h | 5 ++++- 1 file changed, 4 insertions(+), 1 deletion(-) --- a/include/net/sch_generic.h +++ b/include/net/sch_generic.h @@ -785,8 +785,11 @@ static inline struct Qdisc *qdisc_replac 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); Patches currently in stable-queue which might be from khlebnikov@yandex-team.ru are queue-4.12/net_sched-remove-warning-from-qdisc_hash_add.patch queue-4.12/net_sched-fix-order-of-queue-length-updates-in-qdisc_replace.patch queue-4.12/net_sched-sfq-update-hierarchical-backlog-when-drop-packet.patch