[PATCH] fsi: aspeed: fix memory leak on remove

[Guangshuo Li]

fsi_master_aspeed_probe() takes an extra reference to master.dev with
get_device() after registering the FSI master so that the aspeed object
remains valid while the remove path performs its cleanup.

However, fsi_master_aspeed_remove() never drops this extra reference.
After fsi_master_unregister() releases the reference held by device
registration, the extra reference remains and prevents the device
release callback from being invoked. As a result,
aspeed_master_release() is never called and the fsi_master_aspeed
object is leaked.

Drop the extra device reference with put_device() after the clock has
been disabled. This allows the reference count to reach zero and
aspeed_master_release() to free the aspeed object.

This issue was found by manual code inspection.

Fixes: 606397d67f41 ("fsi: Add ast2600 master driver")
Cc: stable at vger.kernel.org
Signed-off-by: Guangshuo Li <lgs201920130244 at gmail.com>
---
 drivers/fsi/fsi-master-aspeed.c | 1 +
 1 file changed, 1 insertion(+)

diff --git a/drivers/fsi/fsi-master-aspeed.c b/drivers/fsi/fsi-master-aspeed.c
index aa1380cdff33..d21d06b44350 100644
--- a/drivers/fsi/fsi-master-aspeed.c
+++ b/drivers/fsi/fsi-master-aspeed.c
@@ -652,6 +652,7 @@ static void fsi_master_aspeed_remove(struct platform_device *pdev)
 
 	fsi_master_unregister(&aspeed->master);
 	clk_disable_unprepare(aspeed->clk);
+	put_device(&aspeed->master.dev);
 }
 
 static const struct of_device_id fsi_master_aspeed_match[] = {
-- 
2.43.0