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=-9.2 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,FREEMAIL_FORGED_FROMDOMAIN,FREEMAIL_FROM, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,MENTIONS_GIT_HOSTING, NICE_REPLY_A,SPF_HELO_NONE,SPF_PASS,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 2CBF3C433ED for ; Fri, 2 Apr 2021 21:12:48 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 05DE8610F7 for ; Fri, 2 Apr 2021 21:12:48 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S235285AbhDBVMn (ORCPT ); Fri, 2 Apr 2021 17:12:43 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:48904 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229722AbhDBVMm (ORCPT ); Fri, 2 Apr 2021 17:12:42 -0400 Received: from mail-wm1-x334.google.com (mail-wm1-x334.google.com [IPv6:2a00:1450:4864:20::334]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 639B6C0613E6; Fri, 2 Apr 2021 14:12:40 -0700 (PDT) Received: by mail-wm1-x334.google.com with SMTP id r14-20020a05600c35ceb029010fe0f81519so1359997wmq.0; Fri, 02 Apr 2021 14:12:40 -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=tTUez4RwARNAYAsQH55/64iDQIBL79zgC/RBPHPmQlo=; b=hZssZsyWk2JzvamYPDFdjRAwzhT+5YhUsi5MUM8C3MwtR/dhwC4WEXT1RHxbmAtuDB yOk8O05m6uwJ1Ekut7sAKveZlRs0Lh3oaA94X7gYQ8APkPDYhp2RqJsOH+T99s5IMfP7 CUO7rU90F7REvV6NtXi7/ZcW2KdZrzpxRRcO2/doGLlOEQiLx0TlMyrTr+OMrV8fJjsN YflQz5MPkKKawkq5WxNVQEtbfUt7l7p9ab1rxWdeBP3LyzWbC/4HUeCiPaS3BmP+6byE JcnMSVFYleTiP9pSX46bL8daiSjEnyw8rOAPNQo9Uq2T5B5a2c8A6mbCQ2BLDv1yHqoa q4Pg== 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=tTUez4RwARNAYAsQH55/64iDQIBL79zgC/RBPHPmQlo=; b=YRPBDFz2C+V8PijLJHR+WNr01tYG7ao3EqhasS4shLhmHomQTlnXtvO0gxPzE3aCQ8 s3Xd3HaOEwQXQsVVWKjvKmbZsGpfKLxg/Y4wfbrbCrtdcfxvjewUwjhHB4wWjPbUVTY+ i+5BagPJ/2qBuyk6RvXFi9pAYMenulVBHdNQxFy35ml66+losel8/Bb45q8AdGWd/ySp MxCC6I6YQ8v6vXd6JXJu+8uv3TtOXr93rFFPqxxRvRFBP1HIjFlTxKDJgGYgXAsDFFhO rTZkI2t7tpfI9Gf2rjM21esV4CRxOXHF0YqQM8CpK+xUTqAg4+oSAeZsNTkHBqqpkASh Yp6Q== X-Gm-Message-State: AOAM530/OM3x9M5KCobL9OcASDQWRiCOQILwQJPVqRnMRv0YHTkdZieg V71IWWOiMxcjcU7Et2J1k353v8iV6h0= X-Google-Smtp-Source: ABdhPJzdJM2Tac4u5/0S9qhkA6wOn1mc7qh9xbqvJxcaIxo5rzWpTzm9fAWL2dAg/megGPfx8K3sEQ== X-Received: by 2002:a1c:750d:: with SMTP id o13mr14416272wmc.76.1617397958718; Fri, 02 Apr 2021 14:12:38 -0700 (PDT) Received: from [192.168.1.101] ([37.166.24.151]) by smtp.gmail.com with ESMTPSA id y18sm16332476wrq.61.2021.04.02.14.12.37 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Fri, 02 Apr 2021 14:12:38 -0700 (PDT) Subject: Re: [PATCH] net: initialize local variables in net/ipv6/mcast.c and net/ipv4/igmp.c To: Eric Dumazet , Phillip Potter Cc: davem@davemloft.net, yoshfuji@linux-ipv6.org, dsahern@kernel.org, kuba@kernel.org, netdev@vger.kernel.org, linux-kernel@vger.kernel.org References: <20210402173617.895-1-phil@philpotter.co.uk> <37f4c845-e63b-87b8-29ec-b28d895326cd@gmail.com> From: Eric Dumazet Message-ID: <05c984b6-140d-112e-9151-4aea6e8e5a80@gmail.com> Date: Fri, 2 Apr 2021 23:12:36 +0200 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:78.0) Gecko/20100101 Thunderbird/78.8.0 MIME-Version: 1.0 In-Reply-To: <37f4c845-e63b-87b8-29ec-b28d895326cd@gmail.com> Content-Type: text/plain; charset=utf-8 Content-Language: en-US Content-Transfer-Encoding: 7bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 4/2/21 10:53 PM, Eric Dumazet wrote: > > > On 4/2/21 8:10 PM, Phillip Potter wrote: >> On Fri, Apr 02, 2021 at 07:49:44PM +0200, Eric Dumazet wrote: >>> >>> >>> On 4/2/21 7:36 PM, Phillip Potter wrote: >>>> Use memset to initialize two local buffers in net/ipv6/mcast.c, >>>> and another in net/ipv4/igmp.c. Fixes a KMSAN found uninit-value >>>> bug reported by syzbot at: >>>> https://syzkaller.appspot.com/bug?id=0766d38c656abeace60621896d705743aeefed51 >>> >>> >>> According to this link, the bug no longer triggers. >>> >>> Please explain why you think it is still there. >>> >> >> Dear Eric, >> >> It definitely still triggers, tested it on the master branch of >> https://github.com/google/kmsan last night. The patch which fixes the >> crash on that page is the same patch I've sent in. > > Please send the full report (stack trace) I think your patch just silences the real problem. The issue at hand is that TUNSETLINK changes dev->type without making any change to dev->addr_len This is the real issue. If you care about this, please fix tun driver.