Messages in this thread | | | Date | Tue, 16 Sep 2008 12:52:04 +1000 | From | Dave Chinner <> | Subject | Re: 2.6.27-rc6: lockdep warning: iprune_mutex at shrink_icache_memory+0x38/0x1a8 |
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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: [<c01743fb>] shrink_icache_memory+0x38/0x1a8 > > but task is already holding lock: > (&(&ip->i_iolock)->mr_lock){----}, at: [<c021134f>] > 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.
<sigh>
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
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