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=-10.1 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY, SPF_HELO_NONE,SPF_PASS,USER_AGENT_GIT 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 B1B68C33CB3 for ; Thu, 16 Jan 2020 18:51:10 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 8D3432053B for ; Thu, 16 Jan 2020 18:51:10 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1579200670; bh=NgkfrwC0DyssXCbp8oWV3NAEiuEx3mhWhQdfEZBAqJ4=; h=From:To:Cc:Subject:Date:In-Reply-To:References:List-ID:From; b=Q+NfVkwQ+OhnCqBBzeySdiJ8esfhbNeLju8jqUg9/P4Kb2fBno6rI1E97B0V7bX09 2dxAeIaF0pgi0eQC7muJSQEs6vX+nu7kRFYcvtSDYBDIPd9E+dyrbbeXF/PveoDna7 oIF/JeUG6Y2TbjCL7IYvlFPNLX3H/WRzd7Yc6RPs= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2437070AbgAPSvJ (ORCPT ); Thu, 16 Jan 2020 13:51:09 -0500 Received: from mail.kernel.org ([198.145.29.99]:43530 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S2389514AbgAPRIx (ORCPT ); Thu, 16 Jan 2020 12:08:53 -0500 Received: from sasha-vm.mshome.net (c-73-47-72-35.hsd1.nh.comcast.net [73.47.72.35]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id 6187224679; Thu, 16 Jan 2020 17:08:51 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1579194532; bh=NgkfrwC0DyssXCbp8oWV3NAEiuEx3mhWhQdfEZBAqJ4=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=0iJsqs1E5zxUZcZ+BAzP4TWqmZ71cRvcDaqcY1HEu7/plYiKNb9rjUoNYENxVmUBY cdUA0yMGowPPyroNJNpDCYR1C+ndK3+GtPDYpaJs06Ad7ov8p/VfZurrpHhO/HYapF o1ITvgj6/xtf9/NXJ/ZU0FvddzPYeqnSC3k2+l9k= From: Sasha Levin To: linux-kernel@vger.kernel.org, stable@vger.kernel.org Cc: Jakub Kicinski , Dirk van der Merwe , Cong Wang , "David S . Miller" , Sasha Levin , netem@lists.linux-foundation.org, netdev@vger.kernel.org Subject: [PATCH AUTOSEL 4.19 420/671] net: netem: fix backlog accounting for corrupted GSO frames Date: Thu, 16 Jan 2020 12:00:58 -0500 Message-Id: <20200116170509.12787-157-sashal@kernel.org> X-Mailer: git-send-email 2.20.1 In-Reply-To: <20200116170509.12787-1-sashal@kernel.org> References: <20200116170509.12787-1-sashal@kernel.org> MIME-Version: 1.0 X-stable: review X-Patchwork-Hint: Ignore Content-Transfer-Encoding: 8bit Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Jakub Kicinski [ Upstream commit 177b8007463c4f36c9a2c7ce7aa9875a4cad9bd5 ] When GSO frame has to be corrupted netem uses skb_gso_segment() to produce the list of frames, and re-enqueues the segments one by one. The backlog length has to be adjusted to account for new frames. The current calculation is incorrect, leading to wrong backlog lengths in the parent qdisc (both bytes and packets), and incorrect packet backlog count in netem itself. Parent backlog goes negative, netem's packet backlog counts all non-first segments twice (thus remaining non-zero even after qdisc is emptied). Move the variables used to count the adjustment into local scope to make 100% sure they aren't used at any stage in backports. Fixes: 6071bd1aa13e ("netem: Segment GSO packets on enqueue") Signed-off-by: Jakub Kicinski Reviewed-by: Dirk van der Merwe Acked-by: Cong Wang Signed-off-by: David S. Miller Signed-off-by: Sasha Levin --- net/sched/sch_netem.c | 13 ++++++++----- 1 file changed, 8 insertions(+), 5 deletions(-) diff --git a/net/sched/sch_netem.c b/net/sched/sch_netem.c index 15f8f24c190d..1cd7266140e6 100644 --- a/net/sched/sch_netem.c +++ b/net/sched/sch_netem.c @@ -436,8 +436,7 @@ static int netem_enqueue(struct sk_buff *skb, struct Qdisc *sch, struct netem_skb_cb *cb; struct sk_buff *skb2; struct sk_buff *segs = NULL; - unsigned int len = 0, last_len, prev_len = qdisc_pkt_len(skb); - int nb = 0; + unsigned int prev_len = qdisc_pkt_len(skb); int count = 1; int rc = NET_XMIT_SUCCESS; int rc_drop = NET_XMIT_DROP; @@ -494,6 +493,7 @@ static int netem_enqueue(struct sk_buff *skb, struct Qdisc *sch, segs = netem_segment(skb, sch, to_free); if (!segs) return rc_drop; + qdisc_skb_cb(segs)->pkt_len = segs->len; } else { segs = skb; } @@ -583,6 +583,11 @@ static int netem_enqueue(struct sk_buff *skb, struct Qdisc *sch, finish_segs: if (segs) { + unsigned int len, last_len; + int nb = 0; + + len = skb->len; + while (segs) { skb2 = segs->next; segs->next = NULL; @@ -598,9 +603,7 @@ static int netem_enqueue(struct sk_buff *skb, struct Qdisc *sch, } segs = skb2; } - sch->q.qlen += nb; - if (nb > 1) - qdisc_tree_reduce_backlog(sch, 1 - nb, prev_len - len); + qdisc_tree_reduce_backlog(sch, -nb, prev_len - len); } return NET_XMIT_SUCCESS; } -- 2.20.1