[PATCH] drm/bridge: it6505: fix use-after-free in it6505_parse_dt()

[Wentao Liang]

Move of_node_put(ep) after the endpoint is fully used, otherwise the
node may be freed before being accessed in the if (ep) block.

Fixes: 380d920b582d ("drm/bridge: add it6505 driver to read data-lanes and link-frequencies from dt")
Cc: stable@xxxxxxxxxxxxxxx
Signed-off-by: Wentao Liang <vulab@xxxxxxxxxxx>
---
 drivers/gpu/drm/bridge/ite-it6505.c | 5 ++---
 1 file changed, 2 insertions(+), 3 deletions(-)

diff --git a/drivers/gpu/drm/bridge/ite-it6505.c b/drivers/gpu/drm/bridge/ite-it6505.c
index 89649c17ffad..2e01b331a168 100644
--- a/drivers/gpu/drm/bridge/ite-it6505.c
+++ b/drivers/gpu/drm/bridge/ite-it6505.c
@@ -3371,7 +3371,6 @@ static void it6505_parse_dt(struct it6505 *it6505)
 	}
 
 	ep = of_graph_get_endpoint_by_regs(np, 1, 0);
-	of_node_put(ep);
 
 	if (ep) {
 		len = it6505_get_data_lanes_count(ep, 1, 4);
@@ -3384,14 +3383,13 @@ static void it6505_parse_dt(struct it6505 *it6505)
 			*max_lane_count = MAX_LANE_COUNT;
 			dev_err(dev, "error data-lanes, use default");
 		}
+		of_node_put(ep);
 	} else {
 		*max_lane_count = MAX_LANE_COUNT;
 		dev_err(dev, "error endpoint, use default");
 	}
 
 	ep = of_graph_get_endpoint_by_regs(np, 0, 0);
-	of_node_put(ep);
-
 	if (ep) {
 		len = of_property_read_variable_u64_array(ep,
 							  "link-frequencies",
@@ -3410,6 +3408,7 @@ static void it6505_parse_dt(struct it6505 *it6505)
 			dev_err(dev, "error link frequencies, use default");
 			*max_dpi_pixel_clock = DPI_PIXEL_CLK_MAX;
 		}
+		of_node_put(ep);
 	} else {
 		dev_err(dev, "error endpoint, use default");
 		*max_dpi_pixel_clock = DPI_PIXEL_CLK_MAX;
-- 
2.34.1