Re: [WIP PATCH 06/15] drm/i915: Keep malloc references to MST ports

From: Daniel Vetter
Date: Fri Dec 14 2018 - 04:33:02 EST


On Thu, Dec 13, 2018 at 08:25:35PM -0500, Lyude Paul wrote:
> So that the ports stay around until we've destroyed the connectors, in
> order to ensure that we don't pass an invalid pointer to any MST helpers
> once we introduce the new MST VCPI helpers.
>
> Signed-off-by: Lyude Paul <lyude@xxxxxxxxxx>
> ---
> drivers/gpu/drm/i915/intel_connector.c | 4 ++++
> drivers/gpu/drm/i915/intel_dp_mst.c | 2 ++
> 2 files changed, 6 insertions(+)
>
> diff --git a/drivers/gpu/drm/i915/intel_connector.c b/drivers/gpu/drm/i915/intel_connector.c
> index 18e370f607bc..37d2c644f4b8 100644
> --- a/drivers/gpu/drm/i915/intel_connector.c
> +++ b/drivers/gpu/drm/i915/intel_connector.c
> @@ -95,6 +95,10 @@ void intel_connector_destroy(struct drm_connector *connector)
> intel_panel_fini(&intel_connector->panel);
>
> drm_connector_cleanup(connector);
> +
> + if (intel_connector->port)

We set this as the first thing in intel_dp_add_mst_connector, so this
check isn't doing anything.

> + drm_dp_mst_put_port_malloc(intel_connector->port);
> +
> kfree(connector);
> }
>
> diff --git a/drivers/gpu/drm/i915/intel_dp_mst.c b/drivers/gpu/drm/i915/intel_dp_mst.c
> index f05427b74e34..4d6ced34d465 100644
> --- a/drivers/gpu/drm/i915/intel_dp_mst.c
> +++ b/drivers/gpu/drm/i915/intel_dp_mst.c
> @@ -484,6 +484,8 @@ static struct drm_connector *intel_dp_add_mst_connector(struct drm_dp_mst_topolo
> if (ret)
> goto err;
>
> + drm_dp_mst_get_port_malloc(port);

Needs to be moved up where we assing intel_connector->port, or it'll
underflow on cleanup on error paths.

> +
> return connector;
>
> err:
> --
> 2.19.2
>

--
Daniel Vetter
Software Engineer, Intel Corporation
http://blog.ffwll.ch