From mboxrd@z Thu Jan 1 00:00:00 1970 From: "Alexander Beregalov" Subject: Re: 2.6.27-rc6: lockdep warning: iprune_mutex at shrink_icache_memory+0x38/0x1a8 Date: Tue, 16 Sep 2008 11:35:20 +0400 Message-ID: References: <20080913233138.GA19576@orion> <20080916025204.GL5811@disturbed> Mime-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit To: "Alexander Beregalov" , rjw-KKrjLPT3xs0@public.gmane.org, linux-kernel-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, kernel-testers-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, linux-fsdevel-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, xfs-VZNHf3L845pBDgjK7y7TUQ@public.gmane.org Return-path: In-Reply-To: <20080916025204.GL5811@disturbed> Content-Disposition: inline Sender: kernel-testers-owner-u79uwXL29TY76Z2rM5mHXA@public.gmane.org List-Id: linux-fsdevel.vger.kernel.org 2008/9/16 Dave Chinner : > 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..... Hi Dave Yes, you already explained a similar message to me, but it was a bug, not false positive. http://lkml.org/lkml/2008/7/3/29 http://lkml.org/lkml/2008/7/3/315 I will try to bisect. It is not a OOM case.