From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751970AbeEFCYe (ORCPT ); Sat, 5 May 2018 22:24:34 -0400 Received: from imap.thunk.org ([74.207.234.97]:43318 "EHLO imap.thunk.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751832AbeEFCYb (ORCPT ); Sat, 5 May 2018 22:24:31 -0400 Date: Sat, 5 May 2018 22:24:28 -0400 From: "Theodore Y. Ts'o" To: syzbot Cc: adilger.kernel@dilger.ca, linux-ext4@vger.kernel.org, linux-kernel@vger.kernel.org, syzkaller-bugs@googlegroups.com, syzkaller@googlegroups.com Subject: Re: kernel panic: EXT4-fs (device loop0): panic forced after error Message-ID: <20180506022428.GQ29205@thunk.org> Mail-Followup-To: "Theodore Y. Ts'o" , syzbot , adilger.kernel@dilger.ca, linux-ext4@vger.kernel.org, linux-kernel@vger.kernel.org, syzkaller-bugs@googlegroups.com, syzkaller@googlegroups.com References: <000000000000019f50056b7f0890@google.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <000000000000019f50056b7f0890@google.com> User-Agent: Mutt/1.9.5 (2018-04-13) X-SA-Exim-Connect-IP: X-SA-Exim-Mail-From: tytso@thunk.org X-SA-Exim-Scanned: No (on imap.thunk.org); SAEximRunCond expanded to false Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Sat, May 05, 2018 at 05:57:02PM -0700, syzbot wrote: > Hello, > > syzbot found the following crash on: > > EXT4-fs error (device loop0): ext4_iget:4756: inode #2: comm > syz-executor909: root inode unallocated > Kernel panic - not syncing: EXT4-fs (device loop0): panic forced after error I don't get why syzbot considers this a bug. It created a corrupted file system, mounted it as root, and said file system had the flag which says, "panic if you find a file system corruption". In what world is this a security bug? There's a *reason* why I've always said people who want to containers to be allowed to mount arbitrary file systems controlled by potentially malicious container users are insane.... I could mark this as a one-off invalid bug, but if syzkaller is going to be generating classes of corrupted file systems like this, and are going to be complaing about how this causes the kernel to crash, then we have a fundamental syzkaller BUG. - Ted