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=-8.5 required=3.0 tests=DKIM_SIGNED,DKIM_VALID, DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_PASS, T_DKIMWL_WL_MED,URIBL_BLOCKED,USER_IN_DEF_DKIM_WL 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 7F6D4C04A6B for ; Wed, 8 May 2019 12:37:58 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 4DE2D20989 for ; Wed, 8 May 2019 12:37:58 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=google.com header.i=@google.com header.b="Fl4PTXyW" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728594AbfEHMh5 (ORCPT ); Wed, 8 May 2019 08:37:57 -0400 Received: from mail-io1-f67.google.com ([209.85.166.67]:44632 "EHLO mail-io1-f67.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726751AbfEHMh4 (ORCPT ); Wed, 8 May 2019 08:37:56 -0400 Received: by mail-io1-f67.google.com with SMTP id v9so13092168ion.11 for ; Wed, 08 May 2019 05:37:56 -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=0VSLwYO4ajiCw1Y1sGYTbNpEZFeZdK3LyxgFKcQp7zw=; b=Fl4PTXyWhYB3k7R9TiGqUO3gRiqHndIFQx5R/XH4YBppV2hu7K24dX31qw3e3yFsXy gu1lb1qkaH7CVg8ns8F4x2VFATP4t2ksvNFcuwqG0E5sVgmMMQQAKY+vAFk2f4SKwVhb SuFD9vUX3LBGQvUXQInG8fGA/r+xOsbS4JGpWt9KVFd32gCUvEGaquV9QGWcw8bJqAJC 5CiUkBfNndHNPa5EqKWQHJS/wfUDJGgD837bHNQf7WGoZlXiRm0Kp2LM9H4V+m8uyob5 aGRtOS0J9+pmsnWOi9Ec1EznWi34ylxBaPH2R8jN5aPjPO3tu3Kk05EO7itnAU5v8KQu s+6g== 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=0VSLwYO4ajiCw1Y1sGYTbNpEZFeZdK3LyxgFKcQp7zw=; b=if+aanh5Ak+IBd1+orQRFjkxipyFC6Ahic0Z4OQLBTJjk1YXjlbxGFzpFYKX4GVK4t zjZ0MBwJAMWCndcQxW0HvJ7ADFFn9kQ1ol7HEKjMig4SxxoPJ3dnCFx6VD8Ghu7it84o 6F72oqRQMqkvIKrGzDRA3GIj9K0anbYWqmRB6aMkDFnuXjDfCbQoUnuU+KbnoxLjiZ5E Ro2vKMYR9wTRKxpSu6Ogq867tHQX6l6tD/h4skFm250P+q05Ua3u4+rL3Hsnl6mHcJde Ci4gE9goncuWbW0w8l8KUy7G7qjtllNZhdm0TTHrKEmlXJegT1sJPSH/yqBz/6zzYVIx YT/g== X-Gm-Message-State: APjAAAUMY0EN51GL7vddK4gFIeiCZyiJvPIKSghfcHd/irPOfjGjgZql rSpOFZRFaOXjsMywBySdOUno9Q0EsdSk+ikt7ASVrw== X-Google-Smtp-Source: APXvYqwqgwN1WWnNZT1cKjwLh1pp35JJJ6nWlhlapspRTelB16v8EwXOj1fRgTsrnQ96pGz0gUiC6BN8mPrfk7czTNo= X-Received: by 2002:a6b:6d06:: with SMTP id a6mr9810801iod.11.1557319075568; Wed, 08 May 2019 05:37:55 -0700 (PDT) MIME-Version: 1.0 References: <000000000000f70a0e0571ad8ffb@google.com> <0000000000007b03eb058653caea@google.com> <20190412130112.GA8384@amd> In-Reply-To: From: Dmitry Vyukov Date: Wed, 8 May 2019 14:37:44 +0200 Message-ID: Subject: Re: WARNING in untrack_pfn To: Julia Lawall Cc: Pavel Machek , syzbot , Borislav Petkov , Dan Williams , Dave Hansen , Dave Jiang , Haozhong Zhang , "H. Peter Anvin" , jacek.anaszewski@gmail.com, LKML , linux-leds@vger.kernel.org, Andy Lutomirski , Ingo Molnar , Paolo Bonzini , Peter Zijlstra , =?UTF-8?B?UmFkaW0gS3LEjW3DocWZ?= , rpurdie@rpsys.net, syzkaller-bugs , Thomas Gleixner , "the arch/x86 maintainers" Content-Type: text/plain; charset="UTF-8" Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Julia Lawall Date: Fri, Apr 12, 2019 at 3:21 PM > On Fri, 12 Apr 2019, Pavel Machek wrote: > > > On Fri 2019-04-12 04:42:01, syzbot wrote: > > > syzbot has bisected this bug to: > > > > > > commit c68729119f4d2993bec3c9cb999ad76de5aeddba > > > Author: Julia Lawall > > > Date: Sat Jul 15 09:58:19 2017 +0000 > > > > > > leds: tlc591xx: add missing of_node_put > > > > > > bisection log: https://syzkaller.appspot.com/x/bisect.txt?x=12cda0f3200000 > > > start commit: 23203e3f Merge branch 'akpm' (patches from Andrew) > > > git tree: upstream > > > final crash: https://syzkaller.appspot.com/x/report.txt?x=11cda0f3200000 > > > console output: https://syzkaller.appspot.com/x/log.txt?x=16cda0f3200000 > > > kernel config: https://syzkaller.appspot.com/x/.config?x=861a3573f4e78ba1 > > > dashboard link: https://syzkaller.appspot.com/bug?extid=e1a4f80c370d2381e49f > > > syz repro: https://syzkaller.appspot.com/x/repro.syz?x=17836d15400000 > > > > > > Reported-by: syzbot+e1a4f80c370d2381e49f@syzkaller.appspotmail.com > > > Fixes: c68729119f4d ("leds: tlc591xx: add missing of_node_put") > > > > > > For information about bisection process see: https://goo.gl/tpsmEJ#bisection > > > > Can you revert c68729119f4d2993bec3c9cb999ad76de5aeddba on master and > > see if it fixes the problem? Because this is hard to believe... > > Likewise, it seems hard to believe that the change is a problem. But > could the problem be elsewhere and triggered by this code? Looking at the bisection log, this looks like a hard to reproduce, flaky crash. Most likely the crash did not fire on one of the commits and that diverted bisection in the wrong direction.