Once cdev_device_add() failed, we should use put_device() to decrement reference count for cleanup. Or it could cause memory leak. Although operations in err_free_ida are similar to the operations in callback function fsi_slave_release(), put_device() is a correct handling operation as comments require when cdev_device_add() fails.

[PATCH RESEND] Once cdev_device_add() failed, we should use put_device() to decrement reference count for cleanup. Or it could cause memory leak. Although operations in err_free_ida are similar to the operations in callback function fsi_slave_release(), put_device() is a correct handling operation as comments require when cdev_device_add() fails.

Ma Ke posted 1 patch 3 months, 2 weeks ago

Download mbox

drivers/fsi/fsi-core.c | 5 ++---
1 file changed, 2 insertions(+), 3 deletions(-)

Expand all Fold all

[PATCH RESEND] Once cdev_device_add() failed, we should use put_device() to decrement reference count for cleanup. Or it could cause memory leak. Although operations in err_free_ida are similar to the operations in callback function fsi_slave_release(), put_device() is a correct handling operation as comments require when cdev_device_add() fails.

Posted by Ma Ke 3 months, 2 weeks ago

As comment of device_add() says, 'if device_add() succeeds, you should
call device_del() when you want to get rid of it. If device_add() has
not succeeded, use only put_device() to drop the reference count'.

Found by code review.

Cc: stable@vger.kernel.org
Fixes: 371975b0b075 ("fsi/core: Fix error paths on CFAM init")
Signed-off-by: Ma Ke <make24@iscas.ac.cn>
---
 drivers/fsi/fsi-core.c | 5 ++---
 1 file changed, 2 insertions(+), 3 deletions(-)

diff --git a/drivers/fsi/fsi-core.c b/drivers/fsi/fsi-core.c
index c6c115993ebc..444878ab9fb1 100644
--- a/drivers/fsi/fsi-core.c
+++ b/drivers/fsi/fsi-core.c
@@ -1084,7 +1084,8 @@ static int fsi_slave_init(struct fsi_master *master, int link, uint8_t id)
 	rc = cdev_device_add(&slave->cdev, &slave->dev);
 	if (rc) {
 		dev_err(&slave->dev, "Error %d creating slave device\n", rc);
-		goto err_free_ida;
+		put_device(&slave->dev);
+		return rc;
 	}
 
 	/* Now that we have the cdev registered with the core, any fatal
@@ -1110,8 +1111,6 @@ static int fsi_slave_init(struct fsi_master *master, int link, uint8_t id)
 
 	return 0;
 
-err_free_ida:
-	fsi_free_minor(slave->dev.devt);
 err_free:
 	of_node_put(slave->dev.of_node);
 	kfree(slave);
-- 
2.17.1

Re: [PATCH RESEND] Once cdev_device_add() failed, we should use put_device() to decrement reference count for cleanup. Or it could cause memory leak. Although operations in err_free_ida are similar to the operations in callback function fsi_slave_release(), put_device() is a correct handling operation as comments require when cdev_device_add() fails.

Posted by Greg KH 3 months, 2 weeks ago

On Wed, Oct 22, 2025 at 04:34:52PM +0800, Ma Ke wrote:
> As comment of device_add() says, 'if device_add() succeeds, you should
> call device_del() when you want to get rid of it. If device_add() has
> not succeeded, use only put_device() to drop the reference count'.
> 
> Found by code review.

Your subject line looks a bit messed up :(