[Intel-gfx] [PATCH 3/3] drm/i915: Warn when releasing a frontbuffer while in use

[Chris Wilson]

Quoting Ville Syrjala (2021-02-09 02:19:18)
> From: Ville Syrjälä <ville.syrjala at linux.intel.com>
> 
> Let's scream if we are about to release a frontbuffer which
> is still in use.
> 
> Signed-off-by: Ville Syrjälä <ville.syrjala at linux.intel.com>
> ---
>  drivers/gpu/drm/i915/display/intel_frontbuffer.c | 2 ++
>  1 file changed, 2 insertions(+)
> 
> diff --git a/drivers/gpu/drm/i915/display/intel_frontbuffer.c b/drivers/gpu/drm/i915/display/intel_frontbuffer.c
> index 7b38eee9980f..6fc6965b6133 100644
> --- a/drivers/gpu/drm/i915/display/intel_frontbuffer.c
> +++ b/drivers/gpu/drm/i915/display/intel_frontbuffer.c
> @@ -224,6 +224,8 @@ static void frontbuffer_release(struct kref *ref)
>         struct drm_i915_gem_object *obj = front->obj;
>         struct i915_vma *vma;
>  
> +       drm_WARN_ON(obj->base.dev, atomic_read(&front->bits));

I had to double check the meaning of bits, and indeed they are cleared
by intel_frontbuffer_track as the scanout is switched away from the
object. A stacktrace here isn't particularly useful for tracking down
the leak, but it is a trivial method to make CI pay attention.

Reviewed-by: Chris Wilson <chris at chris-wilson.co.uk>
-Chris