[PATCH v2] drm/mediatek: fix of_node leak in mtk_drm_probe loop

[WenTao Liang]

In the for_each_child_of_node loop, private->comp_node[comp_id] and
private->mutex_node are assigned via of_node_get without first releasing
any previously stored reference for the same index. When the same comp_id
or mmsys_id matches multiple nodes, earlier node references are
overwritten and permanently leaked.

Suggested-by: Greg KH <gregkh@xxxxxxxxxxxxxxxxxxx>
Fixes: 1ef7ed48356c ("drm/mediatek: Modify mediatek-drm for mt8195 multi mmsys support")
Cc: stable@xxxxxxxxxxxxxxx
Signed-off-by: WenTao Liang <vulab@xxxxxxxxxxx>
---
Changes in v2:
- Fix patch format based on reviewer feedback
---
 drivers/gpu/drm/mediatek/mtk_drm_drv.c | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/drivers/gpu/drm/mediatek/mtk_drm_drv.c b/drivers/gpu/drm/mediatek/mtk_drm_drv.c
index c86a3f54f35b..58860f7071a9 100644
--- a/drivers/gpu/drm/mediatek/mtk_drm_drv.c
+++ b/drivers/gpu/drm/mediatek/mtk_drm_drv.c
@@ -1138,6 +1138,7 @@ static int mtk_drm_probe(struct platform_device *pdev)
 
 			id = of_alias_get_id(node, "mutex");
 			if (id < 0 || id == private->data->mmsys_id) {
+				of_node_put(private->mutex_node);
 				private->mutex_node = of_node_get(node);
 				dev_dbg(dev, "get mutex for mmsys %d", private->data->mmsys_id);
 			}
@@ -1154,6 +1155,7 @@ static int mtk_drm_probe(struct platform_device *pdev)
 		if (!mtk_drm_find_mmsys_comp(private, comp_id))
 			continue;
 
+		of_node_put(private->comp_node[comp_id]);
 		private->comp_node[comp_id] = of_node_get(node);
 
 		/*
-- 
2.39.5 (Apple Git-154)