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=-5.3 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS, URIBL_BLOCKED,USER_AGENT_SANE_1 autolearn=no 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 5A2C7C433DB for ; Fri, 8 Jan 2021 14:08:21 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 26DBB23A02 for ; Fri, 8 Jan 2021 14:08:21 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727355AbhAHOIC (ORCPT ); Fri, 8 Jan 2021 09:08:02 -0500 Received: from mx2.suse.de ([195.135.220.15]:53400 "EHLO mx2.suse.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1725926AbhAHOIC (ORCPT ); Fri, 8 Jan 2021 09:08:02 -0500 X-Virus-Scanned: by amavisd-new at test-mx.suse.de Received: from relay2.suse.de (unknown [195.135.221.27]) by mx2.suse.de (Postfix) with ESMTP id 8DA8CAD11; Fri, 8 Jan 2021 14:07:20 +0000 (UTC) Received: by ds.suse.cz (Postfix, from userid 10065) id 257EFDA6E9; Fri, 8 Jan 2021 15:05:30 +0100 (CET) Date: Fri, 8 Jan 2021 15:05:30 +0100 From: David Sterba To: Dmitry Vyukov Cc: syzbot , syzkaller-bugs , LKML , linux-btrfs@vger.kernel.org Subject: Re: KASAN: null-ptr-deref Write in start_transaction Message-ID: <20210108140529.GX6430@twin.jikos.cz> Reply-To: dsterba@suse.cz Mail-Followup-To: dsterba@suse.cz, Dmitry Vyukov , syzbot , syzkaller-bugs , LKML , linux-btrfs@vger.kernel.org References: <00000000000053e36405b3c538fc@google.com> <0000000000008f60c505b84f2cd0@google.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: User-Agent: Mutt/1.5.23.1-rc1 (2014-03-12) Precedence: bulk List-ID: X-Mailing-List: linux-btrfs@vger.kernel.org On Fri, Jan 08, 2021 at 10:17:25AM +0100, Dmitry Vyukov wrote: > On Thu, Jan 7, 2021 at 2:11 PM syzbot > wrote: > > > > syzbot suspects this issue was fixed by commit: > > > > commit f30bed83426c5cb9fce6cabb3f7cc5a9d5428fcc > > Author: Filipe Manana > > Date: Fri Nov 13 11:24:17 2020 +0000 > > > > btrfs: remove unnecessary attempt to drop extent maps after adding inline extent > > > > bisection log: https://syzkaller.appspot.com/x/bisect.txt?x=13ddc30b500000 > > start commit: 521b619a Merge tag 'linux-kselftest-kunit-fixes-5.10-rc3' .. > > git tree: upstream > > kernel config: https://syzkaller.appspot.com/x/.config?x=61033507391c77ff > > dashboard link: https://syzkaller.appspot.com/bug?extid=6700bca07dff187809c4 > > syz repro: https://syzkaller.appspot.com/x/repro.syz?x=14a07ab2500000 > > C reproducer: https://syzkaller.appspot.com/x/repro.c?x=10fe69c6500000 > > > > If the result looks correct, please mark the issue as fixed by replying with: > > > > #syz fix: btrfs: remove unnecessary attempt to drop extent maps after adding inline extent > > > > For information about bisection process see: https://goo.gl/tpsmEJ#bisection > > #syz fix: btrfs: remove unnecessary attempt to drop extent maps after > adding inline extent I have looked at the report and suspected fix yestereday and was not sure that it's really the right fix. The commit removes some call so it all looks like an accidental fix and something still might be going on. So I'm a bit surprised that you mark it as fixed. It will make the syzbot report go away so from that POV ok and we'll know if it happens again, but I'd expect at least some analysis before closing the report.