Hi Alexy, On Thu, 27 Jun 2013 15:02:31 +1000 Alexey Kardashevskiy wrote: > > +/* Allows an external user (for example, KVM) to unlock an IOMMU group */ > +static void vfio_group_del_external_user(struct file *filep) > +{ > + struct vfio_group *group = filep->private_data; > + > + BUG_ON(filep->f_op != &vfio_group_fops); We usually reserve BUG_ON for situations where there is no way to continue running or continuing will corrupt the running kernel. Maybe WARN_ON() and return? -- Cheers, Stephen Rothwell sfr@canb.auug.org.au