From mboxrd@z Thu Jan 1 00:00:00 1970 From: Hannes Frederic Sowa Subject: Re: [PATCH] ipv6: udp packets following an UFO enqueued packet need also be handled by UFO Date: Wed, 2 Oct 2013 01:25:34 +0200 Message-ID: <20131001232534.GM10771@order.stressinduktion.org> References: <20130921042700.GB8070@order.stressinduktion.org> <20130930114343.GA6356@minipsycho.brq.redhat.com> <20130930172312.GE10771@order.stressinduktion.org> <20131001105837.GA1424@minipsycho.brq.redhat.com> <20131001120907.GH10771@order.stressinduktion.org> <20131001123214.GI10771@order.stressinduktion.org> <20131001214721.GJ10771@order.stressinduktion.org> Mime-Version: 1.0 Content-Type: text/plain; charset=utf-8 To: Jiri Pirko , netdev@vger.kernel.org, yoshfuji@linux-ipv6.org, davem@davemloft.net, kuznet@ms2.inr.ac.ru, jmorris@namei.org, kaber@trash.net, herbert@gondor.apana.org.au, eric.dumazet@gmail.com Return-path: Received: from order.stressinduktion.org ([87.106.68.36]:35067 "EHLO order.stressinduktion.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751784Ab3JAXZf (ORCPT ); Tue, 1 Oct 2013 19:25:35 -0400 Content-Disposition: inline In-Reply-To: <20131001214721.GJ10771@order.stressinduktion.org> Sender: netdev-owner@vger.kernel.org List-ID: On Tue, Oct 01, 2013 at 11:47:21PM +0200, Hannes Frederic Sowa wrote: > The strange thing is that if I don't do the IPV6_MTU setsockopt I don't > get an oops. This is incorrect, it just depends on the size of the writes and on the interface mtu. > IPv4 seems to work without problems, too. I also get kernel oopses from IPv4 now, too. So, skb_is_gso is not accurate enough in the output and we have to check if we already started to append to skb frags. The following diff does resolve this issue in both the IPv4 and IPv6 non-page-append output path but I am not confident if it is correct: diff --git a/include/linux/skbuff.h b/include/linux/skbuff.h index 6d56840..3565450 100644 --- a/include/linux/skbuff.h +++ b/include/linux/skbuff.h @@ -1308,6 +1308,11 @@ static inline int skb_pagelen(const struct sk_buff *skb) return len + skb_headlen(skb); } +static inline bool skb_has_frags(const struct sk_buff *skb) +{ + return skb_shinfo(skb)->nr_frags; +} + /** * __skb_fill_page_desc - initialise a paged fragment in an skb * @skb: buffer containing fragment to be initialised diff --git a/net/ipv4/ip_output.c b/net/ipv4/ip_output.c index 7d8357b..8dc3d8d 100644 --- a/net/ipv4/ip_output.c +++ b/net/ipv4/ip_output.c @@ -836,7 +836,7 @@ static int __ip_append_data(struct sock *sk, csummode = CHECKSUM_PARTIAL; cork->length += length; - if (((length > mtu) || (skb && skb_is_gso(skb))) && + if (((length > mtu) || (skb && skb_has_frags(skb))) && (sk->sk_protocol == IPPROTO_UDP) && (rt->dst.dev->features & NETIF_F_UFO) && !rt->dst.header_len) { err = ip_ufo_append_data(sk, queue, getfrag, from, length, diff --git a/net/ipv6/ip6_output.c b/net/ipv6/ip6_output.c index a54c45c..ded4f6f 100644 --- a/net/ipv6/ip6_output.c +++ b/net/ipv6/ip6_output.c @@ -1227,7 +1227,7 @@ int ip6_append_data(struct sock *sk, int getfrag(void *from, char *to, skb = skb_peek_tail(&sk->sk_write_queue); cork->length += length; if (((length > mtu) || - (skb && skb_is_gso(skb))) && + (skb && skb_has_frags(skb))) && (sk->sk_protocol == IPPROTO_UDP) && (rt->dst.dev->features & NETIF_F_UFO)) { err = ip6_ufo_append_data(sk, getfrag, from, length, Greetings, Hannes