On Thu, Jun 02, 2022 at 07:19:48PM +0200, Eric Farman wrote: > diff --git a/drivers/s390/cio/vfio_ccw_private.h b/drivers/s390/cio/vfio_ccw_private.h > index 3833204bd388..be238cf277ff 100644 > +++ b/drivers/s390/cio/vfio_ccw_private.h > @@ -135,6 +135,8 @@ static inline struct vfio_ccw_private *vfio_ccw_get_private(struct subchannel *s > return NULL; > > private = dev_get_drvdata(&sch->dev); > + if (private && !vfio_device_try_get(&private->vdev)) > + private = NULL; I didn't try to check everything, but obviously any of the null checks in prior patches that are eventually converted to this call should not be made into WARN_ON's.. This looks OK too Jason