From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1756403AbYIPCwY (ORCPT ); Mon, 15 Sep 2008 22:52:24 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1753926AbYIPCwM (ORCPT ); Mon, 15 Sep 2008 22:52:12 -0400 Received: from ipmail05.adl2.internode.on.net ([203.16.214.145]:26217 "EHLO ipmail05.adl2.internode.on.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753827AbYIPCwL (ORCPT ); Mon, 15 Sep 2008 22:52:11 -0400 X-IronPort-Anti-Spam-Filtered: true X-IronPort-Anti-Spam-Result: ApoEAHy7zkh5LD0i/2dsb2JhbAC4UoFl X-IronPort-AV: E=Sophos;i="4.32,405,1217773800"; d="scan'208";a="207122590" Date: Tue, 16 Sep 2008 12:52:04 +1000 From: Dave Chinner To: Alexander Beregalov Cc: rjw@sisk.pl, linux-kernel@vger.kernel.org, kernel-testers@vger.kernel.org, linux-fsdevel@vger.kernel.org, xfs@oss.sgi.com Subject: Re: 2.6.27-rc6: lockdep warning: iprune_mutex at shrink_icache_memory+0x38/0x1a8 Message-ID: <20080916025204.GL5811@disturbed> Mail-Followup-To: Alexander Beregalov , rjw@sisk.pl, linux-kernel@vger.kernel.org, kernel-testers@vger.kernel.org, linux-fsdevel@vger.kernel.org, xfs@oss.sgi.com References: <20080913233138.GA19576@orion> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20080913233138.GA19576@orion> User-Agent: Mutt/1.5.18 (2008-05-17) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Sun, Sep 14, 2008 at 03:31:38AM +0400, Alexander Beregalov wrote: > Hi > > [ INFO: possible circular locking dependency detected ] > 2.6.27-rc6-00034-gd1c6d2e #3 > ------------------------------------------------------- > nfsd/1766 is trying to acquire lock: > (iprune_mutex){--..}, at: [] shrink_icache_memory+0x38/0x1a8 > > but task is already holding lock: > (&(&ip->i_iolock)->mr_lock){----}, at: [] > xfs_ilock+0xa2/0xd6 > > > I read files through nfs and saw delay for few seconds. > System is x86_32, nfs, xfs. > The last working kernel is 2.6.27-rc5, > I do not know yet is it reproducible or not. We need a FAQ for this one. It's a false positive. Google for an explanation - I've explained it 4 or 5 times in the past year and asked that the lockdep folk invent a special annotation for the iprune_mutex (or memory reclaim) because of the way it can cause recursion into the filesystem and hence invert lock orders without causing deadlocks..... Cheers, Dave. -- Dave Chinner david@fromorbit.com