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 D0D0E134BD for ; Thu, 17 Aug 2023 14:45:19 +0000 (UTC) Received: from cwcc.thunk.org (pool-173-48-102-95.bstnma.fios.verizon.net [173.48.102.95]) (authenticated bits=0) (User authenticated as tytso@ATHENA.MIT.EDU) by outgoing.mit.edu (8.14.7/8.12.4) with ESMTP id 37HEj5ra010416 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-GCM-SHA384 bits=256 verify=NOT); Thu, 17 Aug 2023 10:45:07 -0400 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=mit.edu; s=outgoing; t=1692283508; bh=gqsQDXWAnHGIA5wHjYhwbJKrvhNPOC3ihUy4KEVsRbg=; h=Date:From:Subject:Message-ID:MIME-Version:Content-Type; b=VCLuFhlGxpiG5q5PKk9rfLuahkD+JTe4C8shieNnJ+qEvLQFZ5MD7sARRyYRIUIh1 t6xYC9YZ/wG/LMGz770Pe3iSn0XOAGGcgKGzV+pYrfz6blivZRSeispcufwVXEswZj xyAOPJEiym13NldRb6wmoLug5KhV0rqU5BoAv0MUyiVBuzC3ZNPPDTLYBk5JtPtbBj YGkP7SbdQriEmBWs1jFIwpEI+IYqyZMVkcX5tihxzOhoeVNl4u5mPh7ErJUewMn2tT tGO499QHqGlLi8BHiznCT13uO46P6AjauaoUUNGW71RshxHhBBz6l6P1P5895YcUF7 uZvjcskeFMW8w== Received: by cwcc.thunk.org (Postfix, from userid 15806) id 3D6B115C0501; Thu, 17 Aug 2023 10:45:05 -0400 (EDT) Date: Thu, 17 Aug 2023 10:45:05 -0400 From: "Theodore Ts'o" To: Aleksandr Nogikh Cc: syzbot , adilger.kernel@dilger.ca, linux-ext4@vger.kernel.org, linux-fsdevel@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 (3) Message-ID: <20230817144505.GB2247938@mit.edu> References: <000000000000530e0d060312199e@google.com> <20230817142103.GA2247938@mit.edu> 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: On Thu, Aug 17, 2023 at 04:28:33PM +0200, Aleksandr Nogikh wrote: > The console log has the following line: > > [ 60.708717][ T5061] Kernel panic - not syncing: EXT4-fs (device > loop0): panic forced after error > > Can we consider a "panic forced after error" line to be a reliable > indicator that syzbot must ignore the report? Yes. And the file system image that generated this bug should be discarded, because otherwise successive mutations will generate a large number of crashes that syzbot will then need to ignore, thus consuming syzbot resources. Alternatively, you can do the moral equivalent of "tune2fs -e continue foo.img" on any mutated file system seed, which will clear the "panic on error". (The other alternative is "tune2fs -e remount-ro", but given syzbot's desire to find kernel crashes, "tune2fs -e continue" is more likely find ways in which the kernel will find itself into trouble. Some sysadmins will want to chose "remount-ro", however, since that is more likely to limit file system damage once the file system is discovered to be corrupted.) - Ted