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=-0.6 required=3.0 tests=DKIM_SIGNED,DKIM_VALID, DKIM_VALID_AU,FREEMAIL_FORGED_FROMDOMAIN,FREEMAIL_FROM, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_PASS 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 CB2AEC433EF for ; Mon, 18 Jun 2018 18:18:52 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 8434B20693 for ; Mon, 18 Jun 2018 18:18:52 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=gmail.com header.i=@gmail.com header.b="hF4rq0Ql" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 8434B20693 Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=gmail.com Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=linux-kernel-owner@vger.kernel.org Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S935923AbeFRSSu (ORCPT ); Mon, 18 Jun 2018 14:18:50 -0400 Received: from mail-pf0-f193.google.com ([209.85.192.193]:32820 "EHLO mail-pf0-f193.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S935585AbeFRSSs (ORCPT ); Mon, 18 Jun 2018 14:18:48 -0400 Received: by mail-pf0-f193.google.com with SMTP id b17-v6so8583411pfi.0; Mon, 18 Jun 2018 11:18:48 -0700 (PDT) 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=8E4VHY5KWLPP9XG6ex40CyQdmNZ4MTEKwJVQ+JO1M0A=; b=hF4rq0Qlfp4TRUnF2vSh/V+Z54RbdnZKvW+tEdZzn9q38YTzxjfo5Dtw++PhgQPHcQ Inli1bKjyagRQRv3ypDA6Za7fozqdJxATnPl5ETduiHkOeB/9BwrpV/iS16oRsoB7SWp 7z2YKumM8t0v5yp8EFIUsRjJzY18epCD37+UMFscSjWOfAE3ApezmUuAKB2sfYajqzDU gfxs54OV2R8EVRpNmLTHjnlk4ZY7yCzMFECkFyp81x5wJyi6oeaTLmye9uuNGOFswWNz MfY0kvnL8ywak/ALPuLNGWntP4TJL05ZA+sNubb3NMzdm63wo0d5eayHjnHe4NYQfwAI IdDg== 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=8E4VHY5KWLPP9XG6ex40CyQdmNZ4MTEKwJVQ+JO1M0A=; b=oXGp6e/eFZq2GvXUqhEh3YsX3kPhf4yoA9JmUCDm3FaZ3vtuR7E06AA6XxjO6zskFg gjis1FhGFlWRL/u+LVUEGUCaH48HMfolp+JDbocThOFYQ2tc9O0fS9lKzaEY4YUATMKP 8ZTuZE/hHeBkImjZZl98m67FY0iJO9TDclp78InZhixB0/5ajjH2MkgGacSt5BAr1aCn e3PcjwL4V0aXD/Xbp1Wgz8u9EbwJdufnDp8Y7X0b53r2Jpkcl4dqRu/of5S5oJ+feDOe MKRXq7MpF1bBsZJRTC7BtHXii1q20M23IIfWavSSQNbwDoBkjs6qA97PbfW5MALS7kZo BR5Q== X-Gm-Message-State: APt69E0+ok2Y/qtxxyaRZtU7Sc/ovYDXBtZ1KAMDfqBCm2T11F8LVs8H +/ggoD0X5Wp2lai8nbGD73s= X-Google-Smtp-Source: ADUXVKKupLLhxZ8SvciRSdVxXaRA/akwzX7wuMcKChO4/94G9j4ffulSZbRsdC+f0jI9ui8ecO6jlw== X-Received: by 2002:a62:ca99:: with SMTP id y25-v6mr14512434pfk.187.1529345928277; Mon, 18 Jun 2018 11:18:48 -0700 (PDT) Received: from ?IPv6:2620:15c:2c1:200:55c7:81e6:c7d8:94b? ([2620:15c:2c1:200:55c7:81e6:c7d8:94b]) by smtp.gmail.com with ESMTPSA id o87-v6sm28910704pfa.106.2018.06.18.11.18.47 (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Mon, 18 Jun 2018 11:18:47 -0700 (PDT) Subject: Re: [PATCH] Revert "net: pskb_trim_rcsum() and CHECKSUM_COMPLETE are friends" To: Andreas Schwab , Eric Dumazet Cc: Mathieu Malaterre , "David S. Miller" , Eric Dumazet , LKML , Christophe LEROY , Meelis Roos , netdev@vger.kernel.org, linuxppc-dev References: <20180615185645.8921-1-malat@debian.org> <9d88677a-f2be-2089-79df-15df4e9a5dd6@gmail.com> <87o9g8geu0.fsf@igel.home> From: Eric Dumazet Message-ID: <816ef746-5278-1d51-1d9d-55593e377681@gmail.com> Date: Mon, 18 Jun 2018 11:18:46 -0700 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:52.0) Gecko/20100101 Thunderbird/52.6.0 MIME-Version: 1.0 In-Reply-To: <87o9g8geu0.fsf@igel.home> Content-Type: text/plain; charset=utf-8 Content-Language: en-US Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 06/18/2018 10:54 AM, Andreas Schwab wrote: > On Jun 17 2018, Eric Dumazet wrote: > >> Oh this is silly, please try : >> >> diff --git a/net/core/skbuff.c b/net/core/skbuff.c >> index c642304f178ce0a4e1358d59e45032a39f76fb3f..54dd9c18ecad817812898d6f335e1794a07dabbe 100644 >> --- a/net/core/skbuff.c >> +++ b/net/core/skbuff.c >> @@ -1845,10 +1845,9 @@ EXPORT_SYMBOL(___pskb_trim); >> int pskb_trim_rcsum_slow(struct sk_buff *skb, unsigned int len) >> { >> if (skb->ip_summed == CHECKSUM_COMPLETE) { >> - int delta = skb->len - len; >> + __wsum csumdiff = skb_checksum(skb, len, skb->len - len, 0); >> >> - skb->csum = csum_sub(skb->csum, >> - skb_checksum(skb, len, delta, 0)); >> + skb->csum = csum_block_sub(skb->csum, csumdiff, len); >> } >> return __pskb_trim(skb, len); >> } > > That doesn't help either. > > Andreas. > Then maybe NIC provided csum is not correct. It does not compute a checksum on all the frame, but part of it. You could use this patch to double check. diff --git a/drivers/net/ethernet/sun/sungem.c b/drivers/net/ethernet/sun/sungem.c index 7a16d40a72d13cf1d522e8a3a396c826fe76f9b9..277859ea73e35271a10b02011120fca248ec8e71 100644 --- a/drivers/net/ethernet/sun/sungem.c +++ b/drivers/net/ethernet/sun/sungem.c @@ -857,6 +857,11 @@ static int gem_rx(struct gem *gp, int work_to_do) csum = (__force __sum16)htons((status & RXDCTRL_TCPCSUM) ^ 0xffff); skb->csum = csum_unfold(csum); + { + __wsum rsum = csum_partial(skb->data + ETH_HLEN, len - ETH_HLEN, 0); + if (csum != csum_fold(rsum)) + pr_err_ratelimited("sungem wrong csum : %x/%x, len %u bytes\n", csum, csum_fold(rsum), len); + } skb->ip_summed = CHECKSUM_COMPLETE; skb->protocol = eth_type_trans(skb, gp->dev);