Re: [PATCH] kvm: fix coalesced_mmio leak on shutdown

[Chris Wright <chrisw@sous-sol.org>]

* Gregory Haskins (gregory.haskins@gmail.com) wrote:
> Chris Wright wrote:
> > * Gregory Haskins (ghaskins@novell.com) wrote:
> >> It would appear that we are invoking kfree() on the wrong pointer in the
> >> destructor for the coalesced_mmio device.  This would result in a potential
> >> leak during shutdown.
> >
> > Happens to work and not leak:
> >
> > struct kvm_coalesced_mmio_dev { 
> >         struct kvm_io_device dev;
> >         struct kvm *kvm;
> >         int nb_zones;
> >         struct kvm_coalesced_mmio_zone zone[KVM_COALESCED_MMIO_ZONE_MAX];
> > };
> >
> >   
> Ah, yes.  That explains it.  Still sloppy, tho.

Definitely.

> >>  static void coalesced_mmio_destructor(struct kvm_io_device *this)
> >>  {
> >> -	kfree(this);
> >> +	struct kvm_coalesced_mmio_dev *dev =
> >> +		(struct kvm_coalesced_mmio_dev *)this->private;
> >>     
> >
> > I think container_of() makes more sense here.
> 
> I was working on that patch when I noticed the "leak" above.  Figured I
> should send the fix out first, in case my container_of patch is shot down.
> 
> Just polishing it up now.  Will send out soon.

Sounds good.

thanks,
-chris