From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from outgoing.mit.edu (outgoing-auth-1.mit.edu [18.9.28.11]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 845FC6FC7 for ; Wed, 28 Dec 2022 23:19:05 +0000 (UTC) Received: from letrec.thunk.org ([172.102.10.27]) (authenticated bits=0) (User authenticated as tytso@ATHENA.MIT.EDU) by outgoing.mit.edu (8.14.7/8.12.4) with ESMTP id 2BSNEEsa004537 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-GCM-SHA384 bits=256 verify=NOT); Wed, 28 Dec 2022 18:14:16 -0500 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=mit.edu; s=outgoing; t=1672269258; bh=LXKS/ahxqLfQUkNJ4Z0fI/tr5BsFkHuEpYjkPn4Nhgg=; h=Date:From:To:Cc:Subject:References:In-Reply-To; b=FjwcaE9miaagM6TdRTQ3A6esjnDUUCl7cA216/QG328iOWM3fXO8E7bVHBx1+4jms YjY6Qj8vgvC+4xuQ+hE7rk4sOEnUVo54qIhbiMT0uT0jl6igfq8AdbYYsLY5mPKJfb B0oxwSBgIqcMtSwCyly/vCUbemLN6vd2V+8XXtEDyMdbQOdGJveaq5e+WZu2ArdLb1 w7oFy6o3nwZnmY/4R+yVWFBJ2T/2PbSCtaNTwT2Mkl1xhTmiPxIiJPctct7AzekLNm edpxocecGLw6VxKtkdP1Qb8heGiF4rjlYmwKaFq4lAGcRvJLV0mYlERDaGFcr1p9Sz bit99nbh8fMtQ== Received: by letrec.thunk.org (Postfix, from userid 15806) id 15D078C0904; Wed, 28 Dec 2022 18:15:09 -0500 (EST) Date: Wed, 28 Dec 2022 18:15:09 -0500 From: "Theodore Ts'o" To: syzbot Cc: adilger.kernel@dilger.ca, linux-ext4@vger.kernel.org, linux-kernel@vger.kernel.org, llvm@lists.linux.dev, nathan@kernel.org, ndesaulniers@google.com, syzkaller-bugs@googlegroups.com, trix@redhat.com Subject: Re: [syzbot] [ext4?] kernel panic: EXT4-fs (device loop0): panic forced after error (2) Message-ID: References: <000000000000e6c7b005f0e90bf1@google.com> Precedence: bulk X-Mailing-List: llvm@lists.linux.dev List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <000000000000e6c7b005f0e90bf1@google.com> On Wed, Dec 28, 2022 at 12:16:41PM -0800, syzbot wrote: > Hello, > > syzbot found the following issue on: > > HEAD commit: 72a85e2b0a1e Merge tag 'spi-fix-v6.2-rc1' of git://git.ker.. > git tree: upstream > console+strace: https://syzkaller.appspot.com/x/log.txt?x=13527f8c480000 > kernel config: https://syzkaller.appspot.com/x/.config?x=4e2d7bfa2d6d5a76 > dashboard link: https://syzkaller.appspot.com/bug?extid=3c45794f522ad93b0eb6 > compiler: Debian clang version 13.0.1-++20220126092033+75e33f71c2da-1~exp1~20220126212112.63, GNU ld (GNU Binutils for Debian) 2.35.2 > syz repro: https://syzkaller.appspot.com/x/repro.syz?x=12d7f2e4480000 > C reproducer: https://syzkaller.appspot.com/x/repro.c?x=10c8d2ac480000 > > Downloadable assets: > disk image: https://storage.googleapis.com/syzbot-assets/510d16df06c8/disk-72a85e2b.raw.xz > vmlinux: https://storage.googleapis.com/syzbot-assets/50ef5477a1d4/vmlinux-72a85e2b.xz > kernel image: https://storage.googleapis.com/syzbot-assets/f2acd6f1189a/bzImage-72a85e2b.xz > mounted in repro: https://storage.googleapis.com/syzbot-assets/6f0bbc430a64/mount_0.gz > > IMPORTANT: if you fix the issue, please add the following tag to the commit: > Reported-by: syzbot+3c45794f522ad93b0eb6@syzkaller.appspotmail.com > > loop0: detected capacity change from 0 to 512 > EXT4-fs error (device loop0): ext4_map_blocks:607: inode #2: block 2: comm syz-executor170: lblock 0 mapped to illegal pblock 2 (length 1) > Kernel panic - not syncing: EXT4-fs (device loop0): panic forced after error So this is a totally bogus Syzbot report. If you use the mount option "errors=panic", and you feed ext4 a corrupted file system, then it *will* issue an "Ext4-fs error" message, and if you tell it to panic, it will panic. So *please* let's not have some crazy Red Hat principal engineer try to file this as a high severity CVE.... This is Working As Intended. And it is Not A Bug. - Ted