From patchwork Tue Apr 26 19:54:40 2016 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Kamal Mostafa X-Patchwork-Id: 615184 Return-Path: X-Original-To: incoming@patchwork.ozlabs.org Delivered-To: patchwork-incoming@bilbo.ozlabs.org Received: from huckleberry.canonical.com (huckleberry.canonical.com [91.189.94.19]) by ozlabs.org (Postfix) with ESMTP id 3qvYkz5Hrhz9sBG; Wed, 27 Apr 2016 05:56:43 +1000 (AEST) Received: from localhost ([127.0.0.1] helo=huckleberry.canonical.com) by huckleberry.canonical.com with esmtp (Exim 4.76) (envelope-from ) id 1av968-0006wK-Ml; Tue, 26 Apr 2016 19:56:40 +0000 Received: from youngberry.canonical.com ([91.189.89.112]) by huckleberry.canonical.com with esmtps (TLS1.0:RSA_AES_256_CBC_SHA1:32) (Exim 4.76) (envelope-from ) id 1av94I-0006JF-0x for kernel-team@lists.ubuntu.com; Tue, 26 Apr 2016 19:54:46 +0000 Received: from 1.general.kamal.us.vpn ([10.172.68.52] helo=fourier) by youngberry.canonical.com with esmtpsa (TLS1.0:RSA_AES_128_CBC_SHA1:16) (Exim 4.76) (envelope-from ) id 1av94F-0008GD-TF; Tue, 26 Apr 2016 19:54:44 +0000 Received: from kamal by fourier with local (Exim 4.86_2) (envelope-from ) id 1av94D-0001Sw-6Z; Tue, 26 Apr 2016 12:54:41 -0700 From: Kamal Mostafa To: Lars Persson Subject: [3.19.y-ckt stable] Patch "net: sched: do not requeue a NULL skb" has been added to the 3.19.y-ckt tree Date: Tue, 26 Apr 2016 12:54:40 -0700 Message-Id: <1461700480-5599-1-git-send-email-kamal@canonical.com> X-Mailer: git-send-email 2.7.4 X-Extended-Stable: 3.19 Cc: Kamal Mostafa , Eric Dumazet , kernel-team@lists.ubuntu.com, "David S . Miller" , Lars Persson X-BeenThere: kernel-team@lists.ubuntu.com X-Mailman-Version: 2.1.14 Precedence: list List-Id: Kernel team discussions List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , MIME-Version: 1.0 Errors-To: kernel-team-bounces@lists.ubuntu.com Sender: kernel-team-bounces@lists.ubuntu.com This is a note to let you know that I have just added a patch titled net: sched: do not requeue a NULL skb to the linux-3.19.y-queue branch of the 3.19.y-ckt extended stable tree which can be found at: http://kernel.ubuntu.com/git/ubuntu/linux.git/log/?h=linux-3.19.y-queue This patch is scheduled to be released in version 3.19.8-ckt20. If you, or anyone else, feels it should not be added to this tree, please reply to this email. For more information about the 3.19.y-ckt tree, see https://wiki.ubuntu.com/Kernel/Dev/ExtendedStable Thanks. -Kamal ---8<------------------------------------------------------------ From 2d1cda5b6628e42d901b608ccda6e36311e06132 Mon Sep 17 00:00:00 2001 From: Lars Persson Date: Tue, 12 Apr 2016 08:45:52 +0200 Subject: net: sched: do not requeue a NULL skb commit 3dcd493fbebfd631913df6e2773cc295d3bf7d22 upstream. A failure in validate_xmit_skb_list() triggered an unconditional call to dev_requeue_skb with skb=NULL. This slowly grows the queue discipline's qlen count until all traffic through the queue stops. We take the optimistic approach and continue running the queue after a failure since it is unknown if later packets also will fail in the validate path. Fixes: 55a93b3ea780 ("qdisc: validate skb without holding lock") Signed-off-by: Lars Persson Acked-by: Eric Dumazet Signed-off-by: David S. Miller Signed-off-by: Kamal Mostafa --- net/sched/sch_generic.c | 5 ++++- 1 file changed, 4 insertions(+), 1 deletion(-) -- 2.7.4 diff --git a/net/sched/sch_generic.c b/net/sched/sch_generic.c index 507edcf..4900354 100644 --- a/net/sched/sch_generic.c +++ b/net/sched/sch_generic.c @@ -159,12 +159,15 @@ int sch_direct_xmit(struct sk_buff *skb, struct Qdisc *q, if (validate) skb = validate_xmit_skb_list(skb, dev); - if (skb) { + if (likely(skb)) { HARD_TX_LOCK(dev, txq, smp_processor_id()); if (!netif_xmit_frozen_or_stopped(txq)) skb = dev_hard_start_xmit(skb, dev, txq, &ret); HARD_TX_UNLOCK(dev, txq); + } else { + spin_lock(root_lock); + return qdisc_qlen(q); } spin_lock(root_lock);