From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: with ECARTIS (v1.0.0; list xfs); Sun, 16 Mar 2008 13:33:43 -0700 (PDT) Received: from larry.melbourne.sgi.com (larry.melbourne.sgi.com [134.14.52.130]) by oss.sgi.com (8.12.11.20060308/8.12.11/SuSE Linux 0.7) with SMTP id m2GKXVce017632 for ; Sun, 16 Mar 2008 13:33:33 -0700 Date: Mon, 17 Mar 2008 07:33:47 +1100 From: David Chinner Subject: Re: INFO: task mount:11202 blocked for more than 120 seconds Message-ID: <20080316203347.GX95344431@sgi.com> References: <20080307224040.GV155259@sgi.com> <20080309213441.GQ155407@sgi.com> <47DA44EB.8000307@redhat.com> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: Sender: xfs-bounce@oss.sgi.com Errors-to: xfs-bounce@oss.sgi.com List-Id: xfs To: Christian Kujau Cc: Milan Broz , David Chinner , LKML , xfs@oss.sgi.com, dm-devel@redhat.com On Sat, Mar 15, 2008 at 12:58:02AM +0100, Christian Kujau wrote: > On Fri, 14 Mar 2008, Milan Broz wrote: > >Yes, there is bug in dm-crypt... > >Please try if the patch here helps: http://lkml.org/lkml/2008/3/14/71 > > Hm, it seems to help the hangs, yes. Applied to today's -git a few hours > ago, the hangs are gone. However, when doing lots of disk I/O, the machine > locks up after a few (10-20) minutes. Sadly, netconsole got nothing :( > > After the first lockup I tried again and shortly after bootup I got: False positive. Memory reclaim can inverts the order of iprune_mutex and the normal inode locking orders. i.e. Both of these are possible: do_something() enter memory reclaim iprune_mutex inode lock or do_something() inode lock do_something_else enter memory reclaim iprune_mutex inode lock on different inode So depending on what is seen first (in this case the first), the second will trip lockdep. Neither are a deadlock, because the inode lock held before memory reclaim is a referenced inode and will *never* be on the free list for memory reclaim to deadlock on.... Cheers, Dave. -- Dave Chinner Principal Engineer SGI Australian Software Group