Messages in this thread | | | Subject | Re: circular locking dependency detected panic in filldir when CONFIG_PROVE_LOCKING=y | From | Trond Myklebust <> | Date | Fri, 18 Sep 2009 17:39:01 -0400 |
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On Fri, 2009-09-18 at 17:15 -0400, Joe Korty wrote: > I experienced a might_fault panic from NFS's use of filldir > in a 2.6.31 kernel compiled with CONFIG_PROVE_LOCKING=y. > > Looking at filldir, I see it is accessing user space with > __put_dir's (which are inatomic) and with one copy_to_user > (which is not inatomic). It is the single copy_to_user > which is causing the might_fault panic. > > It doesn't make any sense to be mixing use of inatomic > and non-inatomic services in filldir. Either all should be > the inatomic version, or none should be. > > The might_fault condition being reported by the panic looks > real to me, so I suspect the wrong answer is converting > everything to the inatomic version, since that just > suppresses the circular dependency check while leaving > the circular dependency in place.
Yes. This is known... Please see http://thread.gmane.org/gmane.linux.nfs/28578 and http://thread.gmane.org/gmane.linux.nfs/27406
I'm still hoping the VM folks can see fit to merge Peter's fix at some point...
Cheers Trond
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