From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail.toke.dk (mail.toke.dk [52.28.52.200]) (using TLSv1.2 with cipher ADH-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by lists.bufferbloat.net (Postfix) with ESMTPS id DB1DE3CB6C for ; Mon, 7 Jan 2019 14:48:30 -0500 (EST) From: =?UTF-8?q?Toke=20H=C3=B8iland-J=C3=B8rgensen?= DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=toke.dk; s=20161023; t=1546890479; bh=dwWAS4whMeSX6i6NqBvBnY/2nAbWuvrWaFkFkfi8iwY=; h=From:To:Cc:Subject:Date:From; b=FMbLy2tRm4fXK1EzHMreQ51i9AIZwyxo/yvWtnDxNxPczT7OsckWIN2H3T/5LQmIZ mAHy5FHTmV+j2cz77d83qXYPFSjAAU0YX9zvnZG+F7h2VgCQ5Hhw0LenB9U/g6BaX7 lI2Nq6OaF3Lbq1UF9kClYWfYjfkn+sw1VTOneHQVAa3Ex9iKzb6aUpr2/z3lcGnQwY rKOLeGd9euuexXjR6oNA2PdHLQlE2hW+lzmlNOa7IzcymNKz5Od6k3fnIurmKc8BSr mkM8h9bRwn36KJ90lvY4u22mmlDFrQCI43v5mqe8pXVyBcpa0K8qDMTIocQT2Th+/Q 18Aoh3E6fbGjw== To: netdev@vger.kernel.org Cc: cake@lists.bufferbloat.net, =?UTF-8?q?Toke=20H=C3=B8iland-J=C3=B8rgensen?= Date: Mon, 7 Jan 2019 20:47:29 +0100 Message-Id: <20190107194733.31138-1-toke@toke.dk> MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Subject: [Cake] [PATCH 0/4] sched: Fix qdisc interactions exposed by using sch_cake as a leaf qdisc X-BeenThere: cake@lists.bufferbloat.net X-Mailman-Version: 2.1.20 Precedence: list List-Id: Cake - FQ_codel the next generation List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Mon, 07 Jan 2019 19:48:31 -0000 This series fixes a couple of issues exposed by running sch_cake as a leaf qdisc in an HFSC tree, which were discovered and reported by Pete Heist. The interaction between CAKE's GSO splitting and the parent qdisc's notion of its own queue length could cause queue stalls. While investigating the report, I also noticed that several qdiscs would dereference the skb pointer after dequeue, which is potentially problematic since the GSO splitting code also frees the original skb. See the individual patches in the series for details. Toke Høiland-Jørgensen (4): sched: Avoid dereferencing skb pointer after child enqueue sched: Fix detection of empty queues in child qdiscs sch_api: Allow reducing queue backlog by a negative value sch_cake: Correctly update parent qlen when splitting GSO packets include/net/sch_generic.h | 3 +-- net/sched/sch_api.c | 3 +-- net/sched/sch_cake.c | 5 +++-- net/sched/sch_cbs.c | 3 ++- net/sched/sch_drr.c | 7 +++++-- net/sched/sch_dsmark.c | 3 ++- net/sched/sch_hfsc.c | 9 +++++---- net/sched/sch_htb.c | 3 ++- net/sched/sch_prio.c | 3 ++- net/sched/sch_qfq.c | 20 ++++++++++++-------- net/sched/sch_tbf.c | 3 ++- 11 files changed, 37 insertions(+), 25 deletions(-) -- 2.20.1