[PATCH] fbdev: hitfb: fix reference leak on failed device registration

[Guangshuo Li <lgs201920130244@gmail.com>]

When platform_device_register() fails in hitfb_init(), the embedded
struct device in hitfb_device has already been initialized by
device_initialize(), but the failure path only unregisters the platform
driver and does not drop the device reference for the current platform
device:

  hitfb_init()
    -> platform_device_register(&hitfb_device)
       -> device_initialize(&hitfb_device.dev)
       -> setup_pdev_dma_masks(&hitfb_device)
       -> platform_device_add(&hitfb_device)

This leads to a reference leak when platform_device_register() fails.
Fix this by calling platform_device_put() before unregistering the
platform driver.

The issue was identified by a static analysis tool I developed and
confirmed by manual review.

Fixes: 048839dc548a5 ("video: hitfb suspend/resume and updates.")
Cc: stable@vger.kernel.org
Signed-off-by: Guangshuo Li <lgs201920130244@gmail.com>
---
 drivers/video/fbdev/hitfb.c | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/drivers/video/fbdev/hitfb.c b/drivers/video/fbdev/hitfb.c
index 97db325df2b4..29708c2d506d 100644
--- a/drivers/video/fbdev/hitfb.c
+++ b/drivers/video/fbdev/hitfb.c
@@ -495,8 +495,10 @@ static int __init hitfb_init(void)
 	ret = platform_driver_register(&hitfb_driver);
 	if (!ret) {
 		ret = platform_device_register(&hitfb_device);
-		if (ret)
+		if (ret) {
+			platform_device_put(&hitfb_device);
 			platform_driver_unregister(&hitfb_driver);
+		}
 	}
 	return ret;
 }
-- 
2.43.0