Re: Circular vma locking with kvm, seems to be mmu notifiers related

[Avi Kivity]

Johannes Weiner wrote:
> Hi Avi,
>
> Avi Kivity <avi@xxxxxxxxxxxx> writes:
>
>   
> > Max Krasnyansky wrote:
> >     
> > > Got this on the latest mainline git.
> > > There are already a couple of lockdep/kvm threads. So maybe it's known.
> > >
> > > =============================================
> > > [ INFO: possible recursive locking detected ]
> > > 2.6.27-rc2 #36
> > > ---------------------------------------------
> > > qemu-system-x86/3445 is trying to acquire lock:
> > >  (&anon_vma->lock){--..}, at: [<ffffffff8029f84d>] mm_take_all_locks+0x8d/0xf0
> > >
> > > but task is already holding lock:
> > >  (&anon_vma->lock){--..}, at: [<ffffffff8029f84d>] mm_take_all_locks+0x8d/0xf0
> > >
> > >   
> > >       
> > Seems to be a false positive.  mmu_take_all_locks takes (surprise!)
> > all anon_vma->locks belonging to an mm, and takes special care not to
> > deadlock while doing this.
> >
> > We need to communicate this to lockdep somehow.
> >     
>
> I think Peter already annotated this in
> 454ed842d55740160334efc9ad56cfef54ed37bc .
>
>   

Excellent, thanks for the info.

--
error compiling committee.c: too many arguments to function

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