From mboxrd@z Thu Jan 1 00:00:00 1970 From: David Miller Subject: Re: [PATCH net v2] gso_segment: Reset skb->mac_len after modifying network header Date: Thu, 13 Sep 2018 12:10:29 -0700 (PDT) Message-ID: <20180913.121029.1793900247036084325.davem@davemloft.net> References: <153670437243.12756.693381878569982309.stgit@alrua-kau> <20180913144306.9077-1-toke@toke.dk> Mime-Version: 1.0 Content-Type: Text/Plain; charset=iso-8859-1 Content-Transfer-Encoding: 8BIT Cc: netdev@vger.kernel.org, cake@lists.bufferbloat.net, edumazet@google.com, dave.taht@gmail.com To: toke@toke.dk Return-path: Received: from shards.monkeyblade.net ([23.128.96.9]:52812 "EHLO shards.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1728397AbeINAVT (ORCPT ); Thu, 13 Sep 2018 20:21:19 -0400 In-Reply-To: <20180913144306.9077-1-toke@toke.dk> Sender: netdev-owner@vger.kernel.org List-ID: From: Toke Høiland-Jørgensen Date: Thu, 13 Sep 2018 16:43:07 +0200 > When splitting a GSO segment that consists of encapsulated packets, the > skb->mac_len of the segments can end up being set wrong, causing packet > drops in particular when using act_mirred and ifb interfaces in > combination with a qdisc that splits GSO packets. > > This happens because at the time skb_segment() is called, network_header > will point to the inner header, throwing off the calculation in > skb_reset_mac_len(). The network_header is subsequently adjust by the > outer IP gso_segment handlers, but they don't set the mac_len. > > Fix this by adding skb_reset_mac_len() calls to both the IPv4 and IPv6 > gso_segment handlers, after they modify the network_header. > > Many thanks to Eric Dumazet for his help in identifying the cause of > the bug. > > Acked-by: Dave Taht > Reviewed-by: Eric Dumazet > Signed-off-by: Toke Høiland-Jørgensen > --- > v2: > - Properly credit Eric for his help > - Add review and ack tags Applied and queued up for -stable, thanks.