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

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 2b5d1c29f6c4
("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: 95983aea8003 ("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

diff --git a/drivers/gpu/drm/nouveau/nouveau_connector.c b/drivers/gpu/drm/nouveau/nouveau_connector.c
index a2e0033..622f6eb 100644 (file)
--- a/drivers/gpu/drm/nouveau/nouveau_connector.c
+++ b/drivers/gpu/drm/nouveau/nouveau_connector.c
@@ -1408,8 +1408,7 @@ 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) {
                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;

                }
 
                ret = nvif_conn_event_ctor(&nv_connector->conn, "kmsHotplug",
                }
 
                ret = nvif_conn_event_ctor(&nv_connector->conn, "kmsHotplug",


@@ -1426,8 +1425,7 @@ nouveau_connector_create(struct drm_device *dev,
                        if (ret) {
                                nvif_event_dtor(&nv_connector->hpd);
                                nvif_conn_dtor(&nv_connector->conn);
                        if (ret) {
                                nvif_event_dtor(&nv_connector->hpd);
                                nvif_conn_dtor(&nv_connector->conn);

-                               kfree(nv_connector);
-                               return ERR_PTR(ret);
+                               goto drm_conn_err;

                        }
                }
        }
                        }
                }
        }


@@ -1475,4 +1473,9 @@ nouveau_connector_create(struct drm_device *dev,
 
        drm_connector_register(connector);
        return connector;
 
        drm_connector_register(connector);
        return connector;

+
+drm_conn_err:
+       drm_connector_cleanup(connector);
+       kfree(nv_connector);
+       return ERR_PTR(ret);

 }
 }