From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-wr0-f198.google.com (mail-wr0-f198.google.com [209.85.128.198]) by kanga.kvack.org (Postfix) with ESMTP id 7F7C66B0038 for ; Mon, 6 Nov 2017 08:33:16 -0500 (EST) Received: by mail-wr0-f198.google.com with SMTP id l18so5932375wrc.23 for ; Mon, 06 Nov 2017 05:33:16 -0800 (PST) Received: from ZenIV.linux.org.uk (zeniv.linux.org.uk. [195.92.253.2]) by mx.google.com with ESMTPS id j17si6806019wmc.32.2017.11.06.05.33.14 for (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Mon, 06 Nov 2017 05:33:14 -0800 (PST) Date: Mon, 6 Nov 2017 13:33:04 +0000 From: Al Viro Subject: Re: possible deadlock in generic_file_write_iter Message-ID: <20171106133304.GS21978@ZenIV.linux.org.uk> References: <94eb2c05f6a018dc21055d39c05b@google.com> <20171106032941.GR21978@ZenIV.linux.org.uk> <20171106131544.GB4359@quack2.suse.cz> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20171106131544.GB4359@quack2.suse.cz> Sender: owner-linux-mm@kvack.org List-ID: To: Jan Kara Cc: Dmitry Vyukov , syzbot , Andrew Morton , Johannes Weiner , jlayton@redhat.com, LKML , linux-mm@kvack.org, npiggin@gmail.com, rgoldwyn@suse.com, ross.zwisler@linux.intel.com, syzkaller-bugs@googlegroups.com On Mon, Nov 06, 2017 at 02:15:44PM +0100, Jan Kara wrote: > > Should we annotate these inodes with different lock types? Or use > > nesting annotations? > > Well, you'd need to have a completely separate set of locking classes for > each filesystem to avoid false positives like these. And that would > increase number of classes lockdep has to handle significantly. So I'm not > sure it's really worth it... Especially when you consider that backing file might be on a filesystem that lives on another loop device. *All* per-{device,fs} locks involved would need classes split that way... -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@kvack.org. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: email@kvack.org