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=-12.7 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,FREEMAIL_FORGED_FROMDOMAIN,FREEMAIL_FROM, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER,MAILING_LIST_MULTI, MENTIONS_GIT_HOSTING,SPF_HELO_NONE,SPF_PASS 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 CCFF3C433E6 for ; Tue, 2 Feb 2021 17:01:34 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 9C25964E35 for ; Tue, 2 Feb 2021 17:01:34 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S237011AbhBBRB2 (ORCPT ); Tue, 2 Feb 2021 12:01:28 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:59030 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S237061AbhBBQ6p (ORCPT ); Tue, 2 Feb 2021 11:58:45 -0500 Received: from mail-ej1-x636.google.com (mail-ej1-x636.google.com [IPv6:2a00:1450:4864:20::636]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id D8D61C061573; Tue, 2 Feb 2021 08:58:30 -0800 (PST) Received: by mail-ej1-x636.google.com with SMTP id bl23so31047918ejb.5; Tue, 02 Feb 2021 08:58:30 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20161025; h=mime-version:references:in-reply-to:from:date:message-id:subject:to :cc; bh=QoFBWNVeW362Fh0rp8McJnSuJrL1LHsgZ+i7Ga7Dn18=; b=O2iZQSgfIE/lc2zb6VH0ZT0VPhAKwYt6lwQVacOkZJ6lTtoM/9vEmiHEVnEuVijguG XGxnv9BvDp4K7FG/w2uMgKwehCttagfv9Nl8f+2zw6YAqNUq62qg1G5L41+cP24P9QE9 k+8+YcEEpFTltAa0jhaB1TbXqMaxtGgv4WbesVDk6PEXMvLcpsq0kSqLdP07+6u3LX+k xbp1SV5D/6Ah2//LmgZ7xtjW/9eBoAD+xlaSE/AKQ55TGH3G5uhyxjYT7+d+PNQvYtEi 3bteKA1aLZaYtV/c2/gL2guGj/5j53QWsQj5WiX5h3fhYjAi8PzBx8y4eJ3JI/5hqUI3 UE7A== 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=QoFBWNVeW362Fh0rp8McJnSuJrL1LHsgZ+i7Ga7Dn18=; b=X8LGx3hUQ31hVj1yYSAfveABS+3z5sJYysGjl5XV08eDVUImLgIe8z9t8XiyM4IxX2 OjBWRbkMubfj8kNFnR5DS6NlDZeHdvpxTQGwQOJf7zMxcUX0jCtQcwTb54vu/VFyCm9Z XvEPt9FBl044UX3sVycxMbmz8DsMafqk6U++vPcPesR2xMw7CRkeS9tAPI35/feqI4t/ 9FjcgDFdAuW/efNZoPaxL934ISjLmsFHAGzC1sjMGgMml6L7sbAeF0d8wDDdgGO2tMbc Mg4S4/CTIFppo7rKs355dt9UBSe2nrUcUKgKEv6TiE0k4I1XZ40qkDXHVArnQI/5LeMs wbOA== X-Gm-Message-State: AOAM530Xaq+yXLqWsW6z7SxoeRmcXjCwhiWyMSxHcBqyyqEiIhLTPFdX +tes8Q8aJ6+iBBA1fVntSVVZjxSZaxRP8ruzvEVFolW2IPM= X-Google-Smtp-Source: ABdhPJw1rKGDjesa27/kXYB2k0HXKRAXTuvm+6p7sOpvoQ9Bnr2LhDm7o/CQT6AxL7Uzs1eG5OIR8Pg4pFoMjr8nfsQ= X-Received: by 2002:a17:906:b0c2:: with SMTP id bk2mr23572150ejb.223.1612285109601; Tue, 02 Feb 2021 08:58:29 -0800 (PST) MIME-Version: 1.0 References: <20210201160420.2826895-1-elver@google.com> In-Reply-To: From: Christoph Paasch Date: Tue, 2 Feb 2021 08:58:18 -0800 Message-ID: Subject: Re: [PATCH net-next] net: fix up truesize of cloned skb in skb_prepare_for_shift() To: Eric Dumazet Cc: Marco Elver , LKML , kasan-dev , David Miller , Jakub Kicinski , Jonathan Lemon , Willem de Bruijn , linmiaohe , Guillaume Nault , Dongseok Yi , Yadu Kishore , Al Viro , netdev , Alexander Potapenko , syzbot Content-Type: text/plain; charset="UTF-8" Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Mon, Feb 1, 2021 at 9:58 AM Eric Dumazet wrote: > > On Mon, Feb 1, 2021 at 6:34 PM Marco Elver wrote: > > > > On Mon, 1 Feb 2021 at 17:50, Christoph Paasch > > > > just a few days ago we found out that this also fixes a syzkaller > > > issue on MPTCP (https://github.com/multipath-tcp/mptcp_net-next/issues/136). > > > I confirmed that this patch fixes the issue for us as well: > > > > > > Tested-by: Christoph Paasch > > > > That's interesting, because according to your config you did not have > > KFENCE enabled. Although it's hard to say what exactly caused the > > truesize mismatch in your case, because it clearly can't be KFENCE > > that caused ksize(kmalloc(S))!=ksize(kmalloc(S)) for you. > > Indeed, this seems strange. This might be a different issue. > > Maybe S != S ;) Seems like letting syzkaller run for a few more days made it eventually find the WARN again. As if Marco's change makes it harder for us to trigger the issue. Anyways, you can remove my "Tested-by" ;-) Christoph