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 Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 68549C7EE22 for ; Mon, 15 May 2023 01:15:30 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S237721AbjEOBP3 (ORCPT ); Sun, 14 May 2023 21:15:29 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:37408 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S237798AbjEOBP1 (ORCPT ); Sun, 14 May 2023 21:15:27 -0400 Received: from outgoing.mit.edu (outgoing-auth-1.mit.edu [18.9.28.11]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 3BFE1170B for ; Sun, 14 May 2023 18:15:26 -0700 (PDT) Received: from cwcc.thunk.org (pool-173-48-120-46.bstnma.fios.verizon.net [173.48.120.46]) (authenticated bits=0) (User authenticated as tytso@ATHENA.MIT.EDU) by outgoing.mit.edu (8.14.7/8.12.4) with ESMTP id 34F1FD2l026343 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-GCM-SHA384 bits=256 verify=NOT); Sun, 14 May 2023 21:15:14 -0400 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=mit.edu; s=outgoing; t=1684113315; bh=NUk36MnobZ5doR8W/LOe+yxBh26GENvuifgWegftmzs=; h=Date:From:To:Cc:Subject:References:In-Reply-To; b=kh/l6xzOc2xfI7R6XUEqUmxz+wbGlBanvDKC5eKdp3Cs6nom2RMTTNx54BN8/7+sa TH25DJ00FeQJ/d3D5YAqpSh/fhqgPY1QX4ZxZ3K9Fmu8AfVyZG2yk5Jsl6EFje7vyW 9US2XkAI+e4ezfrYNcWYo5ceVCg5IGnO/lG+o055840atlQUeOXdjeFXEbDja0XE3f FFZcaXEQdIyI3aTNdJxb6sP3eu+zc8gW6xQLXGwKNrQ8J+fTGSR9fJ79qcWvBf8mZ9 VjivQYYQ3dLn1CX4bqxEHOLXRehUwhl6va4jgSFnVYzYHzW3fTsBCQxnJOdsaJfznO osklg0hfRzCfg== Received: by cwcc.thunk.org (Postfix, from userid 15806) id 4617C15C04AC; Sun, 14 May 2023 21:15:13 -0400 (EDT) Date: Sun, 14 May 2023 21:15:13 -0400 From: "Theodore Ts'o" To: "Michael S. Tsirkin" Cc: syzbot , adilger.kernel@dilger.ca, elic@nvidia.com, jasowang@redhat.com, linux-ext4@vger.kernel.org, linux-fsdevel@vger.kernel.org, linux-kernel@vger.kernel.org, parav@nvidia.com, syzkaller-bugs@googlegroups.com Subject: Re: [syzbot] [ext4?] possible deadlock in ext4_setattr Message-ID: <20230515011513.GA1905432@mit.edu> References: <000000000000a74de505f2349eb1@google.com> <000000000000a9377e05fbac4945@google.com> <20230514163907-mutt-send-email-mst@kernel.org> <20230515005321.GB1903212@mit.edu> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20230515005321.GB1903212@mit.edu> Precedence: bulk List-ID: X-Mailing-List: linux-fsdevel@vger.kernel.org On Sun, May 14, 2023 at 08:53:21PM -0400, Theodore Ts'o wrote: > However, somewhere in the bisection, we start seeing this: > > run #0: boot failed: WARNING in kvm_wait ... > > This is a completely different failure signature, and the "WARNING in > kvm_wait" should be ignored, and this should be considered a "git > bisect good". However, the syzkaller bisection doesn't understand > this, and so it gets sent down the primrose path. :-( Sorry, I spoke too soon. It did get this right; it looks like it ignores "boot failed: " messages, although it treats is as one of the 10 tries for a particular commit. I don't see anything obviously wrong with the bisect log, although obviously I'd want to retry some of the "All OK" results to see if somehow things got confused. In any case, there have been a large number of timees where the bisection results have been less than correct, and unfortunately, there's not much that can be done other than just to ignore them. It would be nice to have a human being be able to mark the bisection as Obviously Wrong(tm), and maybe ask it do do a slightly different bisection. Also unfortunate is that I've had more than one case where the problem doesn't reproduce at all using KVM, but only reproduces using #syz test. Which means that manual bisection may be the only way for now to work some of these. - Ted