On 06/27/2013 07:42 PM, Benjamin Herrenschmidt wrote: > On Thu, 2013-06-27 at 16:59 +1000, Stephen Rothwell 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? > > Not even that. This is a user space provided "fd", we shouldn't oops the > kernel because we passed a wrong argument, just return -EINVAL or > something like that (add a return code). I'll change to WARN_ON but... This is going to be called on KVM exit on a file pointer previously verified for correctness. If it is a wrong file*, then something went terribly wrong. -- Alexey -- To unsubscribe from this list: send the line "unsubscribe kvm" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html