From mboxrd@z Thu Jan 1 00:00:00 1970 From: Ingo Molnar Subject: Re: lockdep warning with 2.6.29-rc6-mm1 (mmotm 24-feb-2009) Date: Wed, 4 Mar 2009 18:41:15 +0100 Message-ID: <20090304174115.GE25962@elte.hu> References: <20090304125709.GA6251@balbir.in.ibm.com> <1236173267.5330.7487.camel@laptop> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Cc: balbir@linux.vnet.ibm.com, Andrew Morton , "linux-kernel@vger.kernel.org" , Nick Piggin , Eric Paris , linux-fsdevel To: Peter Zijlstra Return-path: Received: from mx3.mail.elte.hu ([157.181.1.138]:56792 "EHLO mx3.mail.elte.hu" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753514AbZCDRls (ORCPT ); Wed, 4 Mar 2009 12:41:48 -0500 Content-Disposition: inline In-Reply-To: <1236173267.5330.7487.camel@laptop> Sender: linux-fsdevel-owner@vger.kernel.org List-ID: * Peter Zijlstra wrote: > On Wed, 2009-03-04 at 18:27 +0530, Balbir Singh wrote: > > I see the following on my machine. My understanding is that the > > lockdep warning is complaining about a potential deadlock while > > reclaiming, where we could end up waiting on holding inotify_mutex, > > and we could end up calling reclaim with inotify_mutex held. > > > > The race seems rare, since one path shows a new inode being created > > and the other one being deleted. It seems like a false positive unless > > the inode's in question turn out to be potentially the same. > > Its not a false positive until you can guarantee the inodes will _never_ > be the same. > > This thing has been reported numerous times, Ingo even posted > a potential fix for it, Nick poked the inotify people to speak > up, but they have so far been silent on the issue :-( that particular fix is upstream, via: 3023a3e: inotify: fix GFP_KERNEL related deadlock so does this reproduce with latest .29-rc7-ish kernels too - or do we have some other problem in this area too? Ingo