From 4772ff03df8094fd99d28de5fcf5df3a3e9c68bb Mon Sep 17 00:00:00 2001 From: Maarten Lankhorst Date: Tue, 11 Aug 2015 09:54:29 +0200 Subject: drm/dp/mst: Remove port after removing connector. The port is removed synchronously, but the connector delayed. This causes a use after free which can cause a kernel BUG with slug_debug=FPZU. This is fixed by freeing the port after the connector. This fixes a regression introduced with 6b8eeca65b18ae77e175cc2b6571731f0ee413bf "drm/dp/mst: close deadlock in connector destruction." Cc: stable@vger.kernel.org Cc: Dave Airlie Signed-off-by: Maarten Lankhorst Reviewed-by: Daniel Vetter Signed-off-by: Jani Nikula --- drivers/gpu/drm/drm_dp_mst_topology.c | 19 +++++++++++++------ 1 file changed, 13 insertions(+), 6 deletions(-) (limited to 'drivers/gpu/drm/drm_dp_mst_topology.c') diff --git a/drivers/gpu/drm/drm_dp_mst_topology.c b/drivers/gpu/drm/drm_dp_mst_topology.c index 778bbb6425b8..1325eecb0510 100644 --- a/drivers/gpu/drm/drm_dp_mst_topology.c +++ b/drivers/gpu/drm/drm_dp_mst_topology.c @@ -873,9 +873,10 @@ static void drm_dp_destroy_port(struct kref *kref) from an EDID retrieval */ if (port->connector) { mutex_lock(&mgr->destroy_connector_lock); - list_add(&port->connector->destroy_list, &mgr->destroy_connector_list); + list_add(&port->next, &mgr->destroy_connector_list); mutex_unlock(&mgr->destroy_connector_lock); schedule_work(&mgr->destroy_connector_work); + return; } drm_dp_port_teardown_pdt(port, port->pdt); @@ -2660,7 +2661,7 @@ static void drm_dp_tx_work(struct work_struct *work) static void drm_dp_destroy_connector_work(struct work_struct *work) { struct drm_dp_mst_topology_mgr *mgr = container_of(work, struct drm_dp_mst_topology_mgr, destroy_connector_work); - struct drm_connector *connector; + struct drm_dp_mst_port *port; /* * Not a regular list traverse as we have to drop the destroy @@ -2669,15 +2670,21 @@ static void drm_dp_destroy_connector_work(struct work_struct *work) */ for (;;) { mutex_lock(&mgr->destroy_connector_lock); - connector = list_first_entry_or_null(&mgr->destroy_connector_list, struct drm_connector, destroy_list); - if (!connector) { + port = list_first_entry_or_null(&mgr->destroy_connector_list, struct drm_dp_mst_port, next); + if (!port) { mutex_unlock(&mgr->destroy_connector_lock); break; } - list_del(&connector->destroy_list); + list_del(&port->next); mutex_unlock(&mgr->destroy_connector_lock); - mgr->cbs->destroy_connector(mgr, connector); + mgr->cbs->destroy_connector(mgr, port->connector); + + drm_dp_port_teardown_pdt(port, port->pdt); + + if (!port->input && port->vcpi.vcpi > 0) + drm_dp_mst_put_payload_id(mgr, port->vcpi.vcpi); + kfree(port); } } -- cgit v1.2.3-59-g8ed1b