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 Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 71E1DC77B61 for ; Thu, 27 Apr 2023 21:21:27 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1344084AbjD0VVZ (ORCPT ); Thu, 27 Apr 2023 17:21:25 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:56028 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229721AbjD0VVX (ORCPT ); Thu, 27 Apr 2023 17:21:23 -0400 Received: from mail-qv1-xf2e.google.com (mail-qv1-xf2e.google.com [IPv6:2607:f8b0:4864:20::f2e]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 828E73C07 for ; Thu, 27 Apr 2023 14:21:22 -0700 (PDT) Received: by mail-qv1-xf2e.google.com with SMTP id 6a1803df08f44-5ef3ec38bb5so38666686d6.0 for ; Thu, 27 Apr 2023 14:21:22 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20221208; t=1682630481; x=1685222481; h=content-transfer-encoding:mime-version:subject:references :in-reply-to:message-id:cc:to:from:date:from:to:cc:subject:date :message-id:reply-to; bh=ghPSLn3O9manYCq7BMo6kZPb2Vk6PTlTwALbgxE4RYE=; b=RTMlNE7WtittIneuOvZUlFMTc2vRdlxtfXKe0dqWWbyAx3qtleEtgDUEyhNCSBRy+J F3Rowan5+Vz/j4/Vro7YW/q6atwTxP/us5uiQzadNUwkSyO9TKsX0M9js2skWFvbV+va Ao/KXIQj4KrUwrAhmysasiZryyL7JLv0mHiIFfW+EU5zAlcHgcUs8m5FsWBc6KEY1b0X Uz1KcuJFQM+Nbn6G3Da7cYh1O/D4ZCAFOCq+8iheHZKtfSLTMUwlVlnvoTHxzPE1dCJj MbfhGhNagzkvdJNBvq7iJLp1yNfwajVCsviYiFq5iURxZybRkFFB8KUUSZ1/d+J/Xh3M bj8g== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20221208; t=1682630481; x=1685222481; h=content-transfer-encoding:mime-version:subject:references :in-reply-to:message-id:cc:to:from:date:x-gm-message-state:from:to :cc:subject:date:message-id:reply-to; bh=ghPSLn3O9manYCq7BMo6kZPb2Vk6PTlTwALbgxE4RYE=; b=T/fOHtAVjfl/yJDwP5psJUPbvtKYLrHextnb7L06skirFcZtzEvSYc32gkUCOuHBZl rRnZoa1bge6MerJw105i4HkKQRDxRxi1POlT9wak0nk9ZmObVijAzUIz4nHYXv7adYSO v5ilZJzxjYd5T8/Vs/RuqL6aE9WCQo5uXKWwO2vnxGefMxX0osSIzKhorF91FKpBSKHp 1GXxd0dzdOzaPCG6TdVXIwKpfVLwcCS5psCC7mFyeXcaaER00Is8xOvMRcvo1jr/ALa3 CyniwPNDQy/CDCOvAcCUrlgqGt/cmkI7y4ueBXoJlkBwJYOrbPyCluz8HJxrVzxPEGhz M29A== X-Gm-Message-State: AC+VfDyf1kmzs7zRBUlSgb8Pz9xVA7a+N1dsfZIofvPmCSXbuAwayvb6 o6dvmUJwy9HOL72/+MHh+PQ= X-Google-Smtp-Source: ACHHUZ47NspusuiMCPI9e44lxSdpF0WQjcqS5PAUFZ0MHdh+O7w76q9LAe+sLeV7NaEqNuCr3Tiadw== X-Received: by 2002:ad4:5f08:0:b0:56a:b623:9b09 with SMTP id fo8-20020ad45f08000000b0056ab6239b09mr5664768qvb.14.1682630481512; Thu, 27 Apr 2023 14:21:21 -0700 (PDT) Received: from localhost (172.174.245.35.bc.googleusercontent.com. [35.245.174.172]) by smtp.gmail.com with ESMTPSA id y5-20020a0cf145000000b005ef650b5e1csm5848281qvl.61.2023.04.27.14.21.21 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Thu, 27 Apr 2023 14:21:21 -0700 (PDT) Date: Thu, 27 Apr 2023 17:21:20 -0400 From: Willem de Bruijn To: David Ahern , Eric Dumazet , "David S . Miller" , Jakub Kicinski , Paolo Abeni Cc: netdev@vger.kernel.org, eric.dumazet@gmail.com, Xin Long , Willem de Bruijn , Coco Li Message-ID: <644ae750da711_26f41f294eb@willemb.c.googlers.com.notmuch> In-Reply-To: <0fa1d0a7-172e-12ca-99c5-d4cf25f2bfef@kernel.org> References: <20230427192404.315287-1-edumazet@google.com> <0fa1d0a7-172e-12ca-99c5-d4cf25f2bfef@kernel.org> Subject: Re: [PATCH net] tcp: fix skb_copy_ubufs() vs BIG TCP Mime-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: 7bit Precedence: bulk List-ID: X-Mailing-List: netdev@vger.kernel.org David Ahern wrote: > On 4/27/23 1:24 PM, Eric Dumazet wrote: > > David Ahern reported crashes in skb_copy_ubufs() caused by TCP tx zerocopy > > using hugepages, and skb length bigger than ~68 KB. > > > > skb_copy_ubufs() assumed it could copy all payload using up to > > MAX_SKB_FRAGS order-0 pages. > > > > This assumption broke when BIG TCP was able to put up to 512 KB per skb. > > Just an FYI - the problem was triggered at 128kB. > > > > > We did not hit this bug at Google because we use CONFIG_MAX_SKB_FRAGS=45 > > and limit gso_max_size to 180000. > > > > A solution is to use higher order pages if needed. > > > > Fixes: 7c4e983c4f3c ("net: allow gso_max_size to exceed 65536") > > Reported-by: David Ahern > > Link: https://lore.kernel.org/netdev/c70000f6-baa4-4a05-46d0-4b3e0dc1ccc8@gmail.com/T/ > > Signed-off-by: Eric Dumazet > > Cc: Xin Long > > Cc: Willem de Bruijn > > Cc: Coco Li > > --- > > net/core/skbuff.c | 20 ++++++++++++++------ > > 1 file changed, 14 insertions(+), 6 deletions(-) > > > > > Reviewed-by: David Ahern > Tested-by: David Ahern Reviewed-by: Willem de Bruijn