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=-11.1 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,FREEMAIL_FORGED_FROMDOMAIN,FREEMAIL_FROM, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH,MAILING_LIST_MULTI,NICE_REPLY_A, SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED,USER_AGENT_SANE_1 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 7B699C2D0A3 for ; Mon, 9 Nov 2020 19:29:12 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 2D5E72065D for ; Mon, 9 Nov 2020 19:29:12 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=gmail.com header.i=@gmail.com header.b="B8cmZ4Yu" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1730582AbgKIT3J (ORCPT ); Mon, 9 Nov 2020 14:29:09 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:53216 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726691AbgKIT3J (ORCPT ); Mon, 9 Nov 2020 14:29:09 -0500 Received: from mail-wr1-x441.google.com (mail-wr1-x441.google.com [IPv6:2a00:1450:4864:20::441]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id C3198C0613CF; Mon, 9 Nov 2020 11:29:07 -0800 (PST) Received: by mail-wr1-x441.google.com with SMTP id s8so2923056wrw.10; Mon, 09 Nov 2020 11:29:07 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20161025; h=subject:to:cc:references:from:message-id:date:user-agent :mime-version:in-reply-to:content-language:content-transfer-encoding; bh=m6LxZ8aRrjGXNDFB2Tn/gXhpm/LDD8SKjkVf58nA1TY=; b=B8cmZ4Yud/sp/VaPzSBFxk1DQp2ub8gpkUGRKHkTDyg5kSl3+bEvEpS0TSVDppKbPS Kp3bCSt49YWyr1dJMfWfX1Fwli26Hz60oLLvb3j518q8zOHy7kiSV7dO1Tnqfl/rhW4/ M6vvPJ/hpZj+UmL+JtYRZi96mSft+3JfdTYNdVVl0zHP3fdy989fxI074vCzHtz2EB9w Pg3e1GTwUgMx8FQmrei5MW3+2l6H6dTQFBeWclIaZjpNu0e5p8deVG6rxZGF1oPHscvS rWO5RjjD6mYrXM6ZwSMZlOTUsruZSJpkY6LDvQ+n5tJ/pfr3WGu4LXRrENsjfFFsQymz NwbQ== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:subject:to:cc:references:from:message-id:date :user-agent:mime-version:in-reply-to:content-language :content-transfer-encoding; bh=m6LxZ8aRrjGXNDFB2Tn/gXhpm/LDD8SKjkVf58nA1TY=; b=pfavbwSoIqOxiIkKUV8W6+jf70HY4Oo1gdIxvaRqEdmkysSAEfAlyggqFflokIQ3Mh Vk0R8700tHM8XLD+cUK5/wFbD87ZtZqRbYmfJHMi/QxGCKTV3lkq4QqBBmmvgycKCx1e kBLP+Ll1THn6GIb5ca3pgrho0Zq5Shx9Hkdma1MrZ2H8Qr5bObmZHurHrkJ9pPED+BHy TUb+ltaKfKomzpI6rgAW3G+pd9NshMB4TV/TTI/pb8Jp0l/RHbOVlahI7sib+uLxEIS/ Ji+g65hBaCBLag8H4vedjyTxAucNoPaxUwX5clB+Prh6Q9qxPsi4mJeJ7m/6cOvO0GyQ k/Pw== X-Gm-Message-State: AOAM53380bVFLzWQuTu5IxA0DNpLPrWZkkWPnS5zlr5slHQEsS6PYZB/ 1FP4fGgvVIqlovPOi8HIUIMqFdZlGt8= X-Google-Smtp-Source: ABdhPJzTwG/lHfIHnIoiZlxEJdgkQikDIZR5xabq8vsJjPZFoT+QvHLcBzfTJPiprwc5NOwpI9p9qw== X-Received: by 2002:adf:f085:: with SMTP id n5mr19624887wro.293.1604950146185; Mon, 09 Nov 2020 11:29:06 -0800 (PST) Received: from [192.168.8.114] ([37.170.31.34]) by smtp.gmail.com with ESMTPSA id u6sm408969wmj.40.2020.11.09.11.29.04 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Mon, 09 Nov 2020 11:29:05 -0800 (PST) Subject: Re: [PATCH v2 net] net: udp: fix Fast/frag0 UDP GRO To: Alexander Lobakin , Eric Dumazet Cc: "David S. Miller" , Jakub Kicinski , Alexey Kuznetsov , Hideaki YOSHIFUJI , Paolo Abeni , Willem de Bruijn , netdev@vger.kernel.org, linux-kernel@vger.kernel.org References: <0eaG8xtbtKY1dEKCTKUBubGiC9QawGgB3tVZtNqVdY@cp4-web-030.plabs.ch> From: Eric Dumazet Message-ID: <0a7af3fb-d1c4-bedf-4931-5f22f0481491@gmail.com> Date: Mon, 9 Nov 2020 20:29:03 +0100 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:78.0) Gecko/20100101 Thunderbird/78.3.1 MIME-Version: 1.0 In-Reply-To: Content-Type: text/plain; charset=utf-8 Content-Language: en-US Content-Transfer-Encoding: 7bit Precedence: bulk List-ID: X-Mailing-List: netdev@vger.kernel.org On 11/9/20 7:26 PM, Alexander Lobakin wrote: > From: Eric Dumazet > Date: Mon, 9 Nov 2020 18:37:36 +0100 > >> 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/YazU6GEzBdpyZMDMwJirxDX7B4sualpDG68ADZYvJI@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, >>> struct sk_buff *skb) >>> { >>> - struct udphdr *uh = udp_hdr(skb); >>> + struct udphdr *uh = udp_gro_udphdr(skb); >>> struct sk_buff *pp = NULL; >>> struct udphdr *uh2; >>> struct sk_buff *p; >>> unsigned int ulen; >>> int ret = 0; >>> >>> + if (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. > > 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. I will test and submit this patch : diff --git a/include/net/ip.h b/include/net/ip.h index 2d6b985d11ccaa75827b3a15ac3f898d7a193242..e20874059f826eb0f9e899aed556bfbc9c9d71e8 100644 --- a/include/net/ip.h +++ b/include/net/ip.h @@ -99,7 +99,7 @@ static inline void ipcm_init_sk(struct ipcm_cookie *ipcm, #define PKTINFO_SKB_CB(skb) ((struct in_pktinfo *)((skb)->cb)) /* 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..877832bed4713a011a514a2f6f522728c8c89e20 100644 --- a/include/net/udp.h +++ b/include/net/udp.h @@ -164,7 +164,7 @@ static inline void udp_csum_pull_header(struct sk_buff *skb) UDP_SKB_CB(skb)->cscov -= sizeof(struct udphdr); } -typedef struct sock *(*udp_lookup_t)(struct sk_buff *skb, __be16 sport, +typedef struct sock *(*udp_lookup_t)(const struct sk_buff *skb, __be16 sport, __be16 dport); INDIRECT_CALLABLE_DECLARE(struct sk_buff *udp4_gro_receive(struct list_head *, @@ -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 sport, __be32 daddr, __be16 dport, int dif, int sdif, 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); /* UDP uses skb->dev_scratch to cache as much information as possible and avoid diff --git a/net/ipv4/udp.c b/net/ipv4/udp.c index 09f0a23d1a01741d335ce45f25fe70a4e00698c7..8b8dadfea6c9854e6bfaa0fabcb774db39976da3 100644 --- a/net/ipv4/udp.c +++ b/net/ipv4/udp.c @@ -541,7 +541,7 @@ static inline struct sock *__udp4_lib_lookup_skb(struct sk_buff *skb, inet_sdif(skb), udptable, 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) { const struct iphdr *iph = ip_hdr(skb); diff --git a/net/ipv6/udp.c b/net/ipv6/udp.c index 29d9691359b9c49ccb56a11f79e3658b1a76700d..adfe9ca6f516612b5aad6d6c654c7da1dd56a50e 100644 --- a/net/ipv6/udp.c +++ b/net/ipv6/udp.c @@ -276,7 +276,7 @@ static struct sock *__udp6_lib_lookup_skb(struct sk_buff *skb, inet6_sdif(skb), udptable, 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) { const struct ipv6hdr *iph = ipv6_hdr(skb);