Re: [PATCH v3 1/7] drm/i915: Clear i915->display when no longer valid

[Jani Nikula <jani.nikula@intel.com>]

On Thu, 16 Apr 2026, Ville Syrjala <ville.syrjala@linux.intel.com> wrote:
> From: Ville Syrjälä <ville.syrjala@linux.intel.com>
>
> Don't leave a stale i915->display pointer hanging around after
> the display driver has been torn down. Apparently the gt code
> calls into the reset codepaths after this, and if the display
> pointer is still around we may try to access freed memory.
>
> The whole teardown sequence here seems rather suspect. Why is
> display done first and then everything else via the managed
> release? Who the heck knows. Someone really needs to dig into
> this stuff and figure out the proper init/cleanup sequence for
> both i915 (real and mock) and xe...

Yeah. And i915 and xe need to be unified, and changed to call higher
level interfaces instead of deep into display.

Reviewed-by: Jani Nikula <jani.nikula@intel.com>

>
> Cc: Jani Nikula <jani.nikula@intel.com>
> Cc: Jouni Högander <jouni.hogander@intel.com>
> Cc: Maarten Lankhorst <maarten.lankhorst@linux.intel.com>
> Signed-off-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
> ---
>  drivers/gpu/drm/i915/i915_driver.c               | 1 +
>  drivers/gpu/drm/i915/selftests/mock_gem_device.c | 1 +
>  2 files changed, 2 insertions(+)
>
> diff --git a/drivers/gpu/drm/i915/i915_driver.c b/drivers/gpu/drm/i915/i915_driver.c
> index 195e34acef30..d31819758f3d 100644
> --- a/drivers/gpu/drm/i915/i915_driver.c
> +++ b/drivers/gpu/drm/i915/i915_driver.c
> @@ -310,6 +310,7 @@ static void i915_driver_late_release(struct drm_i915_private *dev_priv)
>  	i915_params_free(&dev_priv->params);
>  
>  	intel_display_device_remove(display);
> +	dev_priv->display = NULL;
>  }
>  
>  /**
> diff --git a/drivers/gpu/drm/i915/selftests/mock_gem_device.c b/drivers/gpu/drm/i915/selftests/mock_gem_device.c
> index 27dc0e40a8d7..796c9b070e41 100644
> --- a/drivers/gpu/drm/i915/selftests/mock_gem_device.c
> +++ b/drivers/gpu/drm/i915/selftests/mock_gem_device.c
> @@ -277,6 +277,7 @@ void mock_destroy_device(struct drm_i915_private *i915)
>  	struct device *dev = i915->drm.dev;
>  
>  	intel_display_device_remove(i915->display);
> +	i915->display = NULL;
>  
>  	devres_release_group(dev, NULL);
>  	put_device(dev);

-- 
Jani Nikula, Intel