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=-2.2 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI, SPF_PASS,URIBL_BLOCKED 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 3F1EBC37124 for ; Tue, 22 Jan 2019 00:59:28 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 012DA2089F for ; Tue, 22 Jan 2019 00:59:28 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=broadcom.com header.i=@broadcom.com header.b="dPnPzqYV" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726228AbfAVA71 (ORCPT ); Mon, 21 Jan 2019 19:59:27 -0500 Received: from mail-yb1-f169.google.com ([209.85.219.169]:41494 "EHLO mail-yb1-f169.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1725896AbfAVA70 (ORCPT ); Mon, 21 Jan 2019 19:59:26 -0500 Received: by mail-yb1-f169.google.com with SMTP id j10so7878953ybj.8 for ; Mon, 21 Jan 2019 16:59:26 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=broadcom.com; s=google; h=mime-version:references:in-reply-to:from:date:message-id:subject:to :cc; bh=dRHCtkis966FDuAU6/zTdkEjiS0JrXZjAO0lVpxhMaA=; b=dPnPzqYVhPXjig+sDaPXyG5fc8pkZwQkISmlcv3gvVHN1/AVxOR8/pTEAlW9eizTpU ihJIWjAFnDik7Xm7Jtuv+YfR6mRlsjzWR5qL+O/082RX4HTmRNJGtehOLPKlcvsSmPL0 X8ctlmimB9EzwQK0O25/i7Z+MgkaYBcbvCLGI= X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:mime-version:references:in-reply-to:from:date :message-id:subject:to:cc; bh=dRHCtkis966FDuAU6/zTdkEjiS0JrXZjAO0lVpxhMaA=; b=quWigPrwFPm1RwOlQFtZF42oAPETTpeC5t/UKw57kKGLoPOm2DTfxeSMLLEU2q5hyW a97KRpYjeGsYakFb6N5wF1b2YEV5Hhu9Hnya7/1dcFSm4Tsz58y/+30+Xq4w1L0XilYB acSG5C2EE8/L/Z+Jj9nkpbfxN1s5oFL6haq7Fzb0Wf5b1rpjW2dWZTSw8RqF6+yoNUmv yNU8625knubcQZppSl+jah5zEU00Kykrnhb8tl13+U60/q1oVnYUv4NBgbouRiHZlzOk WtQDyirFosFBrNSBeBBkiLnXCnGE3ItLZT6fnKZwDUiZYv+ZHBe2f+83qwwGfPo9zhuA NmDQ== X-Gm-Message-State: AJcUukd0mTsayr4bgd6mLa9zHVvdB3qSbOm78eMmycOTZZdc0kEWPLay KU9G+LG+LfJounI9FXaXVAXoTs32WehT0gQJiBtrQA== X-Google-Smtp-Source: ALg8bN6Gu8lbCAtNaOPXYjrkIspSXiTvXyR2jUstfqABJX66JgLB8TuBC/ud9K5HkZ366L9S6AT4rNwRvL+Knx2/Beo= X-Received: by 2002:a25:5d7:: with SMTP id 206mr18740065ybf.164.1548118765853; Mon, 21 Jan 2019 16:59:25 -0800 (PST) MIME-Version: 1.0 References: <874la1r0io.fsf@linkitivity.dja.id.au> In-Reply-To: <874la1r0io.fsf@linkitivity.dja.id.au> From: Michael Chan Date: Mon, 21 Jan 2019 16:59:15 -0800 Message-ID: Subject: Re: Stack sends oversize UDP packet to the driver To: Daniel Axtens Cc: Netdev , David Miller Content-Type: text/plain; charset="UTF-8" Sender: netdev-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: netdev@vger.kernel.org On Mon, Jan 21, 2019 at 4:36 PM Daniel Axtens wrote: > I hit a similar sounding issue on a bnx2x - see commit > 8914a595110a6eca69a5e275b323f5d09e18f4f9 > > In that case, a GSO packet with gso_size too large for the firmware was > coming to the bnx2x driver from an ibmveth device via Open vSwitch. I > also toyed with a fix in the stack and ended up fixing just the driver. Hi Daniel, yes I remember the issue that you reported at that time. The current issue is similar but for non-TSO UDP packets. > > I was hoping to get a generic fix in to the stack afterwards, but didn't > get anything finished. Looking back at old branches, it looks like I > considered adding MTU validation to validate_xmit_skb, MTU validation in validate_xmit_skb() would definitely prevent the current reported issue. Perhaps we can add a WARN() when an invalid length is detected so that the underlying issue will be reported and fixed. The current issue is that somehow the dst of the SKB gets changed to "lo" and fragmentation is not done for the proper output device. Thanks.