From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755342Ab3LCVg4 (ORCPT ); Tue, 3 Dec 2013 16:36:56 -0500 Received: from mail-qc0-f173.google.com ([209.85.216.173]:53902 "EHLO mail-qc0-f173.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1755098Ab3LCVgw (ORCPT ); Tue, 3 Dec 2013 16:36:52 -0500 Date: Tue, 3 Dec 2013 16:36:49 -0500 From: Tejun Heo To: Dave Jones , Linux Kernel Mailing List , gregkh@linuxfoundation.org Subject: Re: sysfs: use a separate locking class for open files depending on mmap Message-ID: <20131203213649.GO8277@htj.dyndns.org> References: <20131128051223.45739660885@gitolite.kernel.org> <20131203184324.GA11320@redhat.com> <20131203211028.GN8277@htj.dyndns.org> <20131203211515.GA17951@redhat.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20131203211515.GA17951@redhat.com> User-Agent: Mutt/1.5.21 (2010-09-15) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Hey, On Tue, Dec 03, 2013 at 04:15:15PM -0500, Dave Jones wrote: > > > Somehow I just triggered this trace again, even with this commit applied. > > > The trace is pretty much identical to the old one. > > > > Hah, ain't that weird. That's the trace you reported on the other > > mail, right? I'll follow up on that one. > > just so there's no doubt, here's a fresh one. Argh, found the culprit. The unified mmap path grabs of->mutex to check whether the file implements mmap, which means that if you try to mmap a file which doesn't implement mmap, you still add the locking dependency. I'm working on the fix. Thanks. -- tejun