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=-7.2 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI, NICE_REPLY_A,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 4F75FC63777 for ; Thu, 3 Dec 2020 04:16:53 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id EA34C21D91 for ; Thu, 3 Dec 2020 04:16:52 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727272AbgLCEQg (ORCPT ); Wed, 2 Dec 2020 23:16:36 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:58158 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726430AbgLCEQg (ORCPT ); Wed, 2 Dec 2020 23:16:36 -0500 Received: from merlin.infradead.org (merlin.infradead.org [IPv6:2001:8b0:10b:1231::1]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 28A4CC061A4D for ; Wed, 2 Dec 2020 20:15:56 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=infradead.org; s=merlin.20170209; h=Content-Transfer-Encoding:Content-Type: In-Reply-To:MIME-Version:Date:Message-ID:References:Cc:To:From:Subject:Sender :Reply-To:Content-ID:Content-Description; bh=7OtiwI+RbrOUTcd6ZNTb5KMJE5Y6Y667iZfJzsWfUPc=; b=OnJocBIy36aLw2g2aivCBciMJ2 DwaTc7kKNahT/6+eJsYL0URaJomQcb7YeBIzMNsdo4vDNpnuqDqZxqJaQdXN+COXcNzXqCQOm7h/H GuTQNBpUIk84ZQyHB21S0md8AMyR1Hc2LUQS2SmuEudeoV9Xq856nkMcGl/fDZp84Iwr54yMaJi2B xdGWFYaGGHzZZK3a0rRfM5PhppZoNKf4mf/FKJZqpBFEQ0NfdGKavwht58iT5I9mVP8MvgTRL4NYn Gn/1GKXYURE725RcGHNb6XB9lPBwBxDDjyf1VKDW3U+BInokZMebUdynBP9mbh94FcqpILPbawyl1 3U16Jztg==; Received: from [2601:1c0:6280:3f0::1494] by merlin.infradead.org with esmtpsa (Exim 4.92.3 #3 (Red Hat Linux)) id 1kkg24-0002gW-Br; Thu, 03 Dec 2020 04:15:52 +0000 Subject: Re: WARNING: filesystem loop5 was created with 512 inodes, the real maximum is 511, mounting anyway From: Randy Dunlap To: Dmitry Vyukov , Al Viro Cc: syzbot , LKML , syzkaller-bugs , syzkaller References: <00000000000019cd7c05b515da9a@google.com> <7e108ab1-0b07-50dd-5862-a5121eab6094@infradead.org> <8d5ec04c-4646-3b70-6f6c-ea989e6c2c59@infradead.org> Message-ID: <0bc4dbbe-1adb-de9d-641f-bdc2a02efc8b@infradead.org> Date: Wed, 2 Dec 2020 20:15:47 -0800 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:78.0) Gecko/20100101 Thunderbird/78.4.0 MIME-Version: 1.0 In-Reply-To: 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 12/1/20 1:17 PM, Randy Dunlap wrote: > On 11/30/20 11:47 PM, Dmitry Vyukov wrote: >> On Tue, Dec 1, 2020 at 2:03 AM Randy Dunlap wrote: >>> >>> On 11/30/20 12:43 AM, Dmitry Vyukov wrote: >>>> On Mon, Nov 30, 2020 at 5:29 AM Randy Dunlap wrote: >>>>> >>>>> On 11/27/20 4:32 AM, syzbot wrote: >>>>>> Hello, >>>>>> >>>>>> syzbot found the following issue on: >>>>>> >>>>>> HEAD commit: 418baf2c Linux 5.10-rc5 >>>>>> git tree: upstream >>>>>> console output: https://syzkaller.appspot.com/x/log.txt?x=171555b9500000 >>>>>> kernel config: https://syzkaller.appspot.com/x/.config?x=b81aff78c272da44 >>>>>> dashboard link: https://syzkaller.appspot.com/bug?extid=3fd34060f26e766536ff >>>>>> compiler: gcc (GCC) 10.1.0-syz 20200507 >>>>>> >>>>>> Unfortunately, I don't have any reproducer for this issue yet. >>>>>> >>>>>> IMPORTANT: if you fix the issue, please add the following tag to the commit: >>>>>> Reported-by: syzbot+3fd34060f26e766536ff@syzkaller.appspotmail.com >>>>>> >>>>>> BFS-fs: bfs_fill_super(): loop5 is unclean, continuing >>>>>> BFS-fs: bfs_fill_super(): WARNING: filesystem loop5 was created with 512 inodes, the real maximum is 511, mounting anyway >>>>>> BFS-fs: bfs_fill_super(): Last block not available on loop5: 120 >>>>>> BFS-fs: bfs_fill_super(): loop5 is unclean, continuing >>>>>> BFS-fs: bfs_fill_super(): WARNING: filesystem loop5 was created with 512 inodes, the real maximum is 511, mounting anyway >>>>>> BFS-fs: bfs_fill_super(): Last block not available on loop5: 120 >>>>>> >>>>>> >>>>>> --- >>>>>> This report is generated by a bot. It may contain errors. >>>>>> See https://goo.gl/tpsmEJ for more information about syzbot. >>>>>> syzbot engineers can be reached at syzkaller@googlegroups.com. >>>>>> >>>>>> syzbot will keep track of this issue. See: >>>>>> https://goo.gl/tpsmEJ#status for how to communicate with syzbot. ... >>>> Hi Randy, >>>> >>>> I see this bug was reported with a reproducer: >>>> https://syzkaller.appspot.com/bug?id=a32ebd5db2f7c957b82cf54b97bdecf367bf0421 >>>> I assume it's a dup of this one. >>> >>> Sure, looks the same. >>> >>>> If you need the image itself, you can dump it to a file in the C >>>> reproducer inside of syz_mount_image before mount call. >>> >>> Yes, got that. >>> >>> What outcome or result are you looking for here? >>> Or what do you see as the problem? >> >> Hi Randy, >> >> "WARNING:" in kernel output is supposed to mean a kernel source bug. >> Presence of that kernel bug is what syzbot has reported. >> >> Note: the bug may be a misuse of the "WARNING:" for invalid user >> inputs in output as well :) > > > [adding Al Viro] > > Hi Dmitry, > > I expect that the "WARNING:" message is being interpreted incorrectly here, > but that's a minor issue IMO. > > if (info->si_lasti == BFS_MAX_LASTI) > printf("WARNING: filesystem %s was created with 512 inodes, the real maximum is 511, mounting anyway\n", s->s_id); > ... > > > However, in testing this, I see that the BFS image is not mounted > on /dev/loop# at all. > > 'mount' says: > > # mount -t bfs -o loop bfsfilesyz000.img /mnt/stand > mount: /mnt/stand: mount(2) system call failed: Not a directory. > > (but it is a directory) > > and I have tracked that down to fs/namespace.c::graft_tree() > returning -ENOTDIR, but I don't know why that is happening. > > > Al, can you provide any insights on this? OK, with Al's help, here is the situation. If I use a regular file instead of a directory, the mount command succeeds. The printk() from fs/bfs/inode.c that uses the WARNING: string is not a WARN() or WARN_ON(). It's just a printk(). says: * Do not include "BUG"/"WARNING" in format strings manually to make these * conditions distinguishable from kernel issues. so if I change fs/bfs/inode.c to use "warning:" or "Warning," or "Note:", this little problem should go away. Is that correct? thanks. -- ~Randy