[PATCH] drm/mediatek: Fix pdev reference leak in mtk_drm_bind()

[Wentao Liang]

When the device is not the mmsys master, mtk_drm_bind() returns early
after taking a reference on the disp-mutex device via
of_find_device_by_node(), without ever dropping it: mtk_drm_unbind()
only puts mutex_dev for the master. Drop the reference before returning
from the non-master path.

Fixes: 1ef7ed48356c ("drm/mediatek: Modify mediatek-drm for mt8195 multi mmsys support")
Cc: stable@xxxxxxxxxxxxxxx
Signed-off-by: Wentao Liang <vulab@xxxxxxxxxxx>
---
 drivers/gpu/drm/mediatek/mtk_drm_drv.c | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/drivers/gpu/drm/mediatek/mtk_drm_drv.c b/drivers/gpu/drm/mediatek/mtk_drm_drv.c
index c86a3f54f35b..e46f3ab2673f 100644
--- a/drivers/gpu/drm/mediatek/mtk_drm_drv.c
+++ b/drivers/gpu/drm/mediatek/mtk_drm_drv.c
@@ -638,8 +638,10 @@ static int mtk_drm_bind(struct device *dev)
 	private->mtk_drm_bound = true;
 	private->dev = dev;
 
-	if (!mtk_drm_get_all_drm_priv(dev))
+	if (!mtk_drm_get_all_drm_priv(dev)) {
+		put_device(private->mutex_dev);
 		return 0;
+	}
 
 	drm = drm_dev_alloc(&mtk_drm_driver, dev);
 	if (IS_ERR(drm)) {
-- 
2.34.1