Re: [CI] drm: Ensure ioctls are drained before device unplug

["Thomas Hellström" <thomas.hellstrom@linux.intel.com>]

On Tue, 2026-04-21 at 01:00 -0700, Matthew Brost wrote:
> On Tue, Apr 14, 2026 at 11:15:52AM +0200, Thomas Hellström wrote:
> > There is a check that blocks ioctls after device unplug,
> > but we have no check that running ioctls have actually
> > completed at unplug time. (And for some IOCTLs like
> > fence waits, that actually makes sense).
> > However, implement ioctl draining to have CI check for
> > lockdep issues.
> > 
> > Signed-off-by: Thomas Hellström <thomas.hellstrom@linux.intel.com>
> 
> 
> CI patch, but this seems entirely correct—unless there’s some black
> magic or hand-wavy behavior involved for not protecting IOCTLs
> against
> unplug.
> 
> So…
> 
> Reviewed-by: Matthew Brost <matthew.brost@intel.com>

Thanks for reviewing, Matt. 

Although I think for some Ioctls that can wait extensively for GPU,
like fence waits and exec, we actually need to exit dev when waiting,
otherwise that waiting would block the unplug rather than let the
unplug through to kill the running jobs and terminate the wait.

So requires some careful thinking. Might be best if we set an IOTCTL
flag to indicate that we want this behaviour.

Thomas



> 
> > ---
> >  drivers/gpu/drm/drm_ioctl.c | 11 +++++++----
> >  1 file changed, 7 insertions(+), 4 deletions(-)
> > 
> > diff --git a/drivers/gpu/drm/drm_ioctl.c
> > b/drivers/gpu/drm/drm_ioctl.c
> > index ff193155129e..c87a925f0fe4 100644
> > --- a/drivers/gpu/drm/drm_ioctl.c
> > +++ b/drivers/gpu/drm/drm_ioctl.c
> > @@ -789,19 +789,22 @@ long drm_ioctl_kernel(struct file *file,
> > drm_ioctl_t *func, void *kdata,
> >  {
> >  	struct drm_file *file_priv = file->private_data;
> >  	struct drm_device *dev = file_priv->minor->dev;
> > -	int ret;
> > +	int ret, idx;
> >  
> >  	/* Update drm_file owner if fd was passed along. */
> >  	drm_file_update_pid(file_priv);
> >  
> > -	if (drm_dev_is_unplugged(dev))
> > +	if (!drm_dev_enter(dev, &idx))
> >  		return -ENODEV;
> >  
> >  	ret = drm_ioctl_permit(flags, file_priv);
> >  	if (unlikely(ret))
> > -		return ret;
> > +		goto out;
> >  
> > -	return func(dev, kdata, file_priv);
> > +	ret = func(dev, kdata, file_priv);
> > + out:
> > +	drm_dev_exit(idx);
> > +	return ret;
> >  }
> >  EXPORT_SYMBOL(drm_ioctl_kernel);
> >  
> > -- 
> > 2.53.0
> >