Re: [PATCH v3] vfio: fix deadlock between group lock and kvm lock

[Alex Williamson <alex.williamson@redhat.com>]

On Fri, 3 Feb 2023 16:19:10 -0500
Matthew Rosato <mjrosato@linux.ibm.com> wrote:
> > @@ -350,32 +350,25 @@ void vfio_device_get_kvm_safe(struct vfio_device *device)
> >  
> >  	lockdep_assert_held(&device->dev_set->lock);
> >  
> > -	spin_lock(&device->group->kvm_ref_lock);
> > -	if (!device->group->kvm)
> > -		goto unlock;
> > -
> >  	pfn = symbol_get(kvm_put_kvm);
> >  	if (WARN_ON(!pfn))
> > -		goto unlock;
> > +		return;
> >  
> >  	fn = symbol_get(kvm_get_kvm_safe);
> >  	if (WARN_ON(!fn)) {
> >  		symbol_put(kvm_put_kvm);
> > -		goto unlock;
> > +		return;
> >  	}  
> >  >  	ret = fn(device->group->kvm);  
> 
> s/device->group->kvm/kvm/

Oops, yes.

> With that small change, this looks good to me too (and testing looks
> good too).  Do you want me to send a v4 for one last round of review?

Please do.  Thanks,

Alex