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=-13.4 required=3.0 tests=DKIMWL_WL_MED,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI, MENTIONS_GIT_HOSTING,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED,USER_IN_DEF_DKIM_WL 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 71649C2D0F2 for ; Wed, 1 Apr 2020 09:13:10 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 4706620772 for ; Wed, 1 Apr 2020 09:13:10 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=google.com header.i=@google.com header.b="gePLR3I5" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1730590AbgDAJNJ (ORCPT ); Wed, 1 Apr 2020 05:13:09 -0400 Received: from mail-qv1-f65.google.com ([209.85.219.65]:36503 "EHLO mail-qv1-f65.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1728087AbgDAJNJ (ORCPT ); Wed, 1 Apr 2020 05:13:09 -0400 Received: by mail-qv1-f65.google.com with SMTP id z13so12444486qvw.3 for ; Wed, 01 Apr 2020 02:13:08 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20161025; h=mime-version:references:in-reply-to:from:date:message-id:subject:to :cc; bh=jkMgyGLx/BAkeNtxDN6Xm/ZbanBZQvNQbU7eOJcnXos=; b=gePLR3I5HlC84w7tgJzEsRDClSwTX0vkukGGPouc74j9tPxnFXOnMxG8zqKusXyLSD P1CXTLsHgRD/S8Q8S5YIH4ka/bNjg1DuR3op0rVEU8qu0/3qvutPbOxc2nl/iI4PR1x3 kISWfSQmZqfiL2nFZ6Rb5KCWgl65Wka5UzT/xrbBgOXxVwSphSnqGCN+0f7ErOkgeCzo pdkfIyKq3i2TpWjKqfjvvvBKyxACnt5KZbkN1iV4yOXUi95SDk+EdLX7WIfIWb+0/FFM axOTi9LYHzFUG7NygICZeM4Vfcw9ZoImKssVQE87l7r8QgXtWFHq59KR2dylCJRYjYsK 0DmA== 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=jkMgyGLx/BAkeNtxDN6Xm/ZbanBZQvNQbU7eOJcnXos=; b=h0IpYGS3KdXdK7P0085uhO8/MfV+tGS3XAk6YFmwlJAdrV0tfONMLE2HqldURFAInf MKat7nm2Q84jfEDZGOFITn298cqcd8yNnUWM4yr+zPAtbeY9QAfO4VtQ2RiIGteF6t9Y pfbcfTRV/ooWIvDcYiBFvCl4GeHh3JvMYUmnmnqK2htWWfISOJFNQRTikpYwGVIW+o5A 1oVi7gckg25dB+T+kj3VFRp1lL0vjknEofiN648reqe9rMvEfcdxd5kE1FtIwnbojTKO orHMRchh5b3K2xN4heA7S7pYGi6EbKJQ5Bb4Gh1bJspLAxeolG0gF1pSo0cjJxbWb+XT a4uA== X-Gm-Message-State: ANhLgQ2l0dgutFVF1LV2WXbrJYerY4nLhMPVx69zxnO+4XDQPWuE33ZZ ekjWDHAdM1lQwyuiXDSdoXKnEObLe23TeBw+6V48bw== X-Google-Smtp-Source: ADFU+vs06wImJZ2EPBdCY2ie1qh0IX+7CluGHJHL2V6FICU7OeYMC84ibT4JTW0BL1dvRyCt/qMHZuA5ONrD8dluF/U= X-Received: by 2002:ad4:49d1:: with SMTP id j17mr21052173qvy.80.1585732387345; Wed, 01 Apr 2020 02:13:07 -0700 (PDT) MIME-Version: 1.0 References: <000000000000da6059059fcfdcf9@google.com> <0000000000005b022005a22a0050@google.com> <20200331174116.GA1844017@kroah.com> In-Reply-To: From: Dmitry Vyukov Date: Wed, 1 Apr 2020 11:12:55 +0200 Message-ID: Subject: Re: KASAN: use-after-free Read in skb_release_data (2) To: Grant Grundler , syzkaller Cc: Greg KH , syzbot , David Miller , festevam@gmail.com, Hayes Wang , Johan Hedberg , kernel@pengutronix.de, Linux ARM , linux-bluetooth , dl-linux-imx , LKML , USB list , Marcel Holtmann , nishadkamdar@gmail.com, peter.chen@nxp.com, Prashant Malani , Sascha Hauer , Shawn Guo , syzkaller-bugs Content-Type: text/plain; charset="UTF-8" Sender: linux-usb-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-usb@vger.kernel.org On Tue, Mar 31, 2020 at 7:44 PM Grant Grundler wrote: > > On Tue, Mar 31, 2020 at 10:41 AM Greg KH wrote: > > > > On Tue, Mar 31, 2020 at 10:36:01AM -0700, syzbot wrote: > > > syzbot suspects this bug was fixed by commit: > > > > > > commit d9958306d4be14f4c7466242b38ed3893a7b1386 > > > Author: Nishad Kamdar > > > Date: Sun Mar 15 10:55:07 2020 +0000 > > > > > > USB: chipidea: Use the correct style for SPDX License Identifier > > > > > > bisection log: https://syzkaller.appspot.com/x/bisect.txt?x=16d4940be00000 > > > start commit: 63623fd4 Merge tag 'for-linus' of git://git.kernel.org/pub.. > > > git tree: upstream > > > kernel config: https://syzkaller.appspot.com/x/.config?x=5d2e033af114153f > > > dashboard link: https://syzkaller.appspot.com/bug?extid=a66a7c2e996797bb4acb > > > syz repro: https://syzkaller.appspot.com/x/repro.syz?x=13c25a81e00000 > > > > > > If the result looks correct, please mark the bug fixed by replying with: > > > > > > #syz fix: USB: chipidea: Use the correct style for SPDX License Identifier > > > > I really doubt a comment change fixed a syzbot bug :) > > Just as I don't believe the bug was caused by pmalani's patch to r8152. > > syzbot is just having trouble automatically bisecting/tracking this > bug since it appears only intermittently. Checking if vmlinux changes after applying the patch looked like a smart and simple way to detect all of: - Comment-only change - Documentation-only change - Change to a non-current arch - Changed to non-enabled configs - Changes to tests only But it's not working in reality, there is some bug in kernel or compiler: https://github.com/google/syzkaller/issues/1271#issuecomment-559093018 You may see in this bisection log as well: culprit signature: 85ed07d5a8769c26fa0d170475624841e367ea0d08ea79f55ca450a9e97429a0 parent signature: 2244116b3fcae3bb24003990bcd2b06a03861effee2d94675e527446c3da078f So this commit somehow does very realistically affect the kernel binary. So far nobody figured out why... Before you ask, syzkaller filters out debug info, etc: https://github.com/google/syzkaller/blob/master/pkg/build/linux.go#L168-L178