> -----Original Message-----
> From: Nikula, Jani <jani.nikula@xxxxxxxxx>
> Sent: Tuesday, September 24, 2024 9:00 PM
> To: intel-gfx@xxxxxxxxxxxxxxxxxxxxx; intel-xe@xxxxxxxxxxxxxxxxxxxxx
> Cc: Nikula, Jani <jani.nikula@xxxxxxxxx>; Sean Paul
> <seanpaul@xxxxxxxxxxxx>; Kandpal, Suraj <suraj.kandpal@xxxxxxxxx>;
> Ville Syrjälä <ville.syrjala@xxxxxxxxxxxxxxx>; stable@xxxxxxxxxxxxxxx
> Subject: [PATCH] drm/i915/hdcp: fix connector refcounting
>
> We acquire a connector reference before scheduling an HDCP prop work,
> and expect the work function to release the reference.
>
> However, if the work was already queued, it won't be queued multiple
> times, and the reference is not dropped.
>
> Release the reference immediately if the work was already queued.
>
LGTM,
Reviewed-by: Suraj Kandpal <suraj.kandpal@xxxxxxxxx>
> Fixes: a6597faa2d59 ("drm/i915: Protect workers against disappearing
> connectors")
> Cc: Sean Paul <seanpaul@xxxxxxxxxxxx>
> Cc: Suraj Kandpal <suraj.kandpal@xxxxxxxxx>
> Cc: Ville Syrjälä <ville.syrjala@xxxxxxxxxxxxxxx>
> Cc: <stable@xxxxxxxxxxxxxxx> # v5.10+
> Signed-off-by: Jani Nikula <jani.nikula@xxxxxxxxx>
>
> ---
>
> I don't know that we have any bugs open about this. Or how it would
> manifest itself. Memory leak on driver unload? I just spotted this while
> reading the code for other reasons.
> ---
> drivers/gpu/drm/i915/display/intel_hdcp.c | 10 +++++++---
> 1 file changed, 7 insertions(+), 3 deletions(-)
>
> diff --git a/drivers/gpu/drm/i915/display/intel_hdcp.c
> b/drivers/gpu/drm/i915/display/intel_hdcp.c
> index 2afa92321b08..cad309602617 100644
> --- a/drivers/gpu/drm/i915/display/intel_hdcp.c
> +++ b/drivers/gpu/drm/i915/display/intel_hdcp.c
> @@ -1097,7 +1097,8 @@ static void intel_hdcp_update_value(struct
> intel_connector *connector,
> hdcp->value = value;
> if (update_property) {
> drm_connector_get(&connector->base);
> - queue_work(i915->unordered_wq, &hdcp->prop_work);
> + if (!queue_work(i915->unordered_wq, &hdcp->prop_work))
> + drm_connector_put(&connector->base);
> }
> }
>
> @@ -2531,7 +2532,8 @@ void intel_hdcp_update_pipe(struct
> intel_atomic_state *state,
> mutex_lock(&hdcp->mutex);
> hdcp->value =
> DRM_MODE_CONTENT_PROTECTION_DESIRED;
> drm_connector_get(&connector->base);
> - queue_work(i915->unordered_wq, &hdcp->prop_work);
> + if (!queue_work(i915->unordered_wq, &hdcp->prop_work))
> + drm_connector_put(&connector->base);
> mutex_unlock(&hdcp->mutex);
> }
>
> @@ -2548,7 +2550,9 @@ void intel_hdcp_update_pipe(struct
> intel_atomic_state *state,
> */
> if (!desired_and_not_enabled &&
> !content_protection_type_changed) {
> drm_connector_get(&connector->base);
> - queue_work(i915->unordered_wq, &hdcp-
> >prop_work);
> + if (!queue_work(i915->unordered_wq, &hdcp-
> >prop_work))
> + drm_connector_put(&connector->base);
> +
> }
> }
>
> --
> 2.39.2
