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=-9.8 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH, MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED autolearn=unavailable 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 557E4C2D0A3 for ; Mon, 9 Nov 2020 19:56:41 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id F300F206D8 for ; Mon, 9 Nov 2020 19:56:40 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=pm.me header.i=@pm.me header.b="BtGYhwai" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1731143AbgKIT4j (ORCPT ); Mon, 9 Nov 2020 14:56:39 -0500 Received: from mail-40133.protonmail.ch ([185.70.40.133]:46820 "EHLO mail-40133.protonmail.ch" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1729432AbgKIT4i (ORCPT ); Mon, 9 Nov 2020 14:56:38 -0500 X-Greylist: delayed 153943 seconds by postgrey-1.27 at vger.kernel.org; Mon, 09 Nov 2020 14:56:36 EST Date: Mon, 09 Nov 2020 19:56:28 +0000 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=pm.me; s=protonmail; t=1604951795; bh=TshS9dbkRzzf0kdsqu1zguOjYxDLNBwypCqj78pG4o0=; h=Date:To:From:Cc:Reply-To:Subject:In-Reply-To:References:From; b=BtGYhwaikwC5UxzObPgBEocxhQ5cmBc74WzMPJhI5ueDLvtv/ATp6No1xDkDgzG9w 24ITPp5TUL3iuDM/vMTKpNoz7dgmi98J9FjlzEMopFefx6xQvKgRnQegl5MLTLWG12 zuAcLFZck6VoAxvHi3+VekVd4LRiozxFUwmSUtrrpNRqLPqFREeUEH2Vz5MJZl1ijw l7zYSo9CZnIoftwB0cdr9+zKWHRgr1Itv6yJqTgCMvb+UJwSdMgXaFfpwfs6DJuToG 48Blf7dp7CEYvN4CpokAL5DDCPT3RKkRQUAAGPeRn/YUiUgX/wMPX4hbGny5EHl8J5 D896Vi4r3Xx9w== To: Eric Dumazet From: Alexander Lobakin Cc: Alexander Lobakin , "David S. Miller" , Jakub Kicinski , Alexey Kuznetsov , Hideaki YOSHIFUJI , Paolo Abeni , Willem de Bruijn , Steffen Klassert , netdev@vger.kernel.org, linux-kernel@vger.kernel.org Reply-To: Alexander Lobakin Subject: Re: [PATCH v2 net] net: udp: fix Fast/frag0 UDP GRO Message-ID: In-Reply-To: <0a7af3fb-d1c4-bedf-4931-5f22f0481491@gmail.com> References: <0eaG8xtbtKY1dEKCTKUBubGiC9QawGgB3tVZtNqVdY@cp4-web-030.plabs.ch> <0a7af3fb-d1c4-bedf-4931-5f22f0481491@gmail.com> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: quoted-printable Precedence: bulk List-ID: X-Mailing-List: netdev@vger.kernel.org From: Eric Dumazet Date: Mon, 9 Nov 2020 20:29:03 +0100 > On 11/9/20 7:26 PM, Alexander Lobakin wrote: >> From: Eric Dumazet >> Date: Mon, 9 Nov 2020 18:37:36 +0100 >>=20 >>> On 11/9/20 5:56 PM, Alexander Lobakin wrote: >>>> While testing UDP GSO fraglists forwarding through driver that uses >>>> Fast GRO (via napi_gro_frags()), I was observing lots of out-of-order >>>> iperf packets: >>>> >. >>>> >>>> Since v1 [1]: >>>> - added a NULL pointer check for "uh" as suggested by Willem. >>>> >>>> [1] https://lore.kernel.org/netdev/YazU6GEzBdpyZMDMwJirxDX7B4sualpDG68= ADZYvJI@cp4-web-034.plabs.ch >>>> >>>> Fixes: e20cf8d3f1f7 ("udp: implement GRO for plain UDP sockets.") >>>> Signed-off-by: Alexander Lobakin >>>> --- >>>> net/ipv4/udp_offload.c | 7 ++++++- >>>> 1 file changed, 6 insertions(+), 1 deletion(-) >>>> >>>> diff --git a/net/ipv4/udp_offload.c b/net/ipv4/udp_offload.c >>>> index e67a66fbf27b..7f6bd221880a 100644 >>>> --- a/net/ipv4/udp_offload.c >>>> +++ b/net/ipv4/udp_offload.c >>>> @@ -366,13 +366,18 @@ static struct sk_buff *udp4_ufo_fragment(struct = sk_buff *skb, >>>> static struct sk_buff *udp_gro_receive_segment(struct list_head *head= , >>>> =09=09=09=09=09 struct sk_buff *skb) >>>> { >>>> -=09struct udphdr *uh =3D udp_hdr(skb); >>>> +=09struct udphdr *uh =3D udp_gro_udphdr(skb); >>>> =09struct sk_buff *pp =3D NULL; >>>> =09struct udphdr *uh2; >>>> =09struct sk_buff *p; >>>> =09unsigned int ulen; >>>> =09int ret =3D 0; >>>> >>>> +=09if (unlikely(!uh)) { >>> >>> How uh could be NULL here ? >>> >>> My understanding is that udp_gro_receive() is called >>> only after udp4_gro_receive() or udp6_gro_receive() >>> validated that udp_gro_udphdr(skb) was not NULL. >>=20 >> Right, but only after udp{4,6}_lib_lookup_skb() in certain cases. >> I don't know for sure if their logic can actually edit skb->data, >> so it's better to check from my point of view. > > Not really. This would send a wrong signal to readers of this code. > > I do not think these functions can mess with GRO internals. > > This would be a nightmare, GRO is already way too complex. > > In fact these functions should use a const qualifier > for their " struct sk_buff *skb" argument to prevent future bugs. Agree, you're right. Lack of const qualifiers gave me a doubt that these functions can't edit skbs. They really should use it if they really can't. I'll omit the check in v3. > I will test and submit this patch : That would be a very nice one, thanks. > diff --git a/include/net/ip.h b/include/net/ip.h > index 2d6b985d11ccaa75827b3a15ac3f898d7a193242..e20874059f826eb0f9e899aed= 556bfbc9c9d71e8 100644 > --- a/include/net/ip.h > +++ b/include/net/ip.h > @@ -99,7 +99,7 @@ static inline void ipcm_init_sk(struct ipcm_cookie *ipc= m, > #define PKTINFO_SKB_CB(skb) ((struct in_pktinfo *)((skb)->cb)) > =20 > /* return enslaved device index if relevant */ > -static inline int inet_sdif(struct sk_buff *skb) > +static inline int inet_sdif(const struct sk_buff *skb) > { > #if IS_ENABLED(CONFIG_NET_L3_MASTER_DEV) > if (skb && ipv4_l3mdev_skb(IPCB(skb)->flags)) > diff --git a/include/net/udp.h b/include/net/udp.h > index 295d52a73598277dc5071536f777d1a87e7df1d1..877832bed4713a011a514a2f6= f522728c8c89e20 100644 > --- a/include/net/udp.h > +++ b/include/net/udp.h > @@ -164,7 +164,7 @@ static inline void udp_csum_pull_header(struct sk_buf= f *skb) > UDP_SKB_CB(skb)->cscov -=3D sizeof(struct udphdr); > } > =20 > -typedef struct sock *(*udp_lookup_t)(struct sk_buff *skb, __be16 sport, > +typedef struct sock *(*udp_lookup_t)(const struct sk_buff *skb, __be16 s= port, > __be16 dport); > =20 > INDIRECT_CALLABLE_DECLARE(struct sk_buff *udp4_gro_receive(struct list_h= ead *, > @@ -313,7 +313,7 @@ struct sock *udp4_lib_lookup(struct net *net, __be32 = saddr, __be16 sport, > struct sock *__udp4_lib_lookup(struct net *net, __be32 saddr, __be16 spo= rt, > __be32 daddr, __be16 dport, int dif, int s= dif, > struct udp_table *tbl, struct sk_buff *skb= ); > -struct sock *udp4_lib_lookup_skb(struct sk_buff *skb, > +struct sock *udp4_lib_lookup_skb(const struct sk_buff *skb, > __be16 sport, __be16 dport); > struct sock *udp6_lib_lookup(struct net *net, > const struct in6_addr *saddr, __be16 sport, > @@ -324,7 +324,7 @@ struct sock *__udp6_lib_lookup(struct net *net, > const struct in6_addr *daddr, __be16 dport= , > int dif, int sdif, struct udp_table *tbl, > struct sk_buff *skb); > -struct sock *udp6_lib_lookup_skb(struct sk_buff *skb, > +struct sock *udp6_lib_lookup_skb(const struct sk_buff *skb, > __be16 sport, __be16 dport); > =20 > /* UDP uses skb->dev_scratch to cache as much information as possible an= d avoid > diff --git a/net/ipv4/udp.c b/net/ipv4/udp.c > index 09f0a23d1a01741d335ce45f25fe70a4e00698c7..8b8dadfea6c9854e6bfaa0fab= cb774db39976da3 100644 > --- a/net/ipv4/udp.c > +++ b/net/ipv4/udp.c > @@ -541,7 +541,7 @@ static inline struct sock *__udp4_lib_lookup_skb(stru= ct sk_buff *skb, > inet_sdif(skb), udptable, skb); > } > =20 > -struct sock *udp4_lib_lookup_skb(struct sk_buff *skb, > +struct sock *udp4_lib_lookup_skb(const struct sk_buff *skb, > __be16 sport, __be16 dport) > { > const struct iphdr *iph =3D ip_hdr(skb); > diff --git a/net/ipv6/udp.c b/net/ipv6/udp.c > index 29d9691359b9c49ccb56a11f79e3658b1a76700d..adfe9ca6f516612b5aad6d6c6= 54c7da1dd56a50e 100644 > --- a/net/ipv6/udp.c > +++ b/net/ipv6/udp.c > @@ -276,7 +276,7 @@ static struct sock *__udp6_lib_lookup_skb(struct sk_b= uff *skb, > inet6_sdif(skb), udptable, skb); > } > =20 > -struct sock *udp6_lib_lookup_skb(struct sk_buff *skb, > +struct sock *udp6_lib_lookup_skb(const struct sk_buff *skb, > __be16 sport, __be16 dport) > { > const struct ipv6hdr *iph =3D ipv6_hdr(skb); > Al