drm/nouveau/disp: fix use-after-free in error handling of nouveau_con…

…nector_create

commit 1b254b7 upstream.

We can't simply free the connector after calling drm_connector_init on it.
We need to clean up the drm side first.

It might not fix all regressions from commit 2b5d1c2
("drm/nouveau/disp: PIOR DP uses GPIO for HPD, not PMGR AUX interrupts"),
but at least it fixes a memory corruption in error handling related to
that commit.

Link: https://lore.kernel.org/lkml/20230806213107.GFZNARG6moWpFuSJ9W@fat_crate.local/
Fixes: 95983ae ("drm/nouveau/disp: add connector class")
Signed-off-by: Karol Herbst <kherbst@redhat.com>
Reviewed-by: Lyude Paul <lyude@redhat.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20230814144933.3956959-1-kherbst@redhat.com
Signed-off-by: Karol Herbst <kherbst@redhat.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/gpu/drm/nouveau/nouveau_connector.c

@@ -1407,8 +1407,7 @@ nouveau_connector_create(struct drm_device *dev,
 		ret = nvif_conn_ctor(&disp->disp, nv_connector->base.name, nv_connector->index,
 				     &nv_connector->conn);
 		if (ret) {
-			kfree(nv_connector);
-			return ERR_PTR(ret);
+			goto drm_conn_err;
 		}
 	}
 
@@ -1470,4 +1469,9 @@ nouveau_connector_create(struct drm_device *dev,
 
 	drm_connector_register(connector);
 	return connector;
+
+drm_conn_err:
+	drm_connector_cleanup(connector);
+	kfree(nv_connector);
+	return ERR_PTR(ret);
 }