From: Maarten Lankhorst <maarten.lankhorst@xxxxxxxxxxxxxxx>
This patch has been added to the 4.1 stable tree. If you have any
objections, please let us know.
===============
[ Upstream commit 4772ff03df8094fd99d28de5fcf5df3a3e9c68bb ]
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@xxxxxxxxxxxxxxx
Cc: Dave Airlie <airlied@xxxxxxxxxx>
Signed-off-by: Maarten Lankhorst <maarten.lankhorst@xxxxxxxxxxxxxxx>
Reviewed-by: Daniel Vetter <daniel.vetter@xxxxxxxx>
Signed-off-by: Jani Nikula <jani.nikula@xxxxxxxxx>
Signed-off-by: Sasha Levin <sasha.levin@xxxxxxxxxx>
---
drivers/gpu/drm/drm_dp_mst_topology.c | 19 +++++++++++++------
include/drm/drm_crtc.h | 2 --
2 files changed, 13 insertions(+), 8 deletions(-)
diff --git a/drivers/gpu/drm/drm_dp_mst_topology.c b/drivers/gpu/drm/drm_dp_mst_topology.c
index 6010976..d7d70e8 100644
--- a/drivers/gpu/drm/drm_dp_mst_topology.c
+++ b/drivers/gpu/drm/drm_dp_mst_topology.c
@@ -871,9 +871,10 @@ 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);
@@ -2738,7 +2739,7 @@ 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
@@ -2747,15 +2748,21 @@ 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);
}
}
diff --git a/include/drm/drm_crtc.h b/include/drm/drm_crtc.h
index 5423358..ca71c03 100644
--- a/include/drm/drm_crtc.h
+++ b/include/drm/drm_crtc.h
@@ -731,8 +731,6 @@ struct drm_connector {
uint8_t num_h_tile, num_v_tile;
uint8_t tile_h_loc, tile_v_loc;
uint16_t tile_h_size, tile_v_size;
-
- struct list_head destroy_list;
};
/**
--
2.5.0
--
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