On Wed, 28 Feb 2018 17:39:53 +0530
Arvind Yadav [off-list ref] wrote:

On Wednesday 28 February 2018 05:26 PM, Cornelia Huck wrote:

quoted

On Wed, 28 Feb 2018 17:14:55 +0530
Arvind Yadav [off-list ref] wrote:
 

quoted

On Wednesday 28 February 2018 04:00 PM, Cornelia Huck wrote:  

quoted

On Wed, 28 Feb 2018 15:24:16 +0530
Arvind Yadav [off-list ref] wrote:
    

quoted

Free memory, if afiucv_iucv_init is not successful and
removing a IUCV driver.

Signed-off-by: Arvind Yadav <redacted>
---
   net/iucv/af_iucv.c | 5 ++++-
   1 file changed, 4 insertions(+), 1 deletion(-)

diff --git a/net/iucv/af_iucv.c b/net/iucv/af_iucv.c
index 1e8cc7b..eb0995a 100644
--- a/net/iucv/af_iucv.c
+++ b/net/iucv/af_iucv.c

@@ -2433,9 +2433,11 @@ static int afiucv_iucv_init(void)
   	af_iucv_dev->driver = &af_iucv_driver;
   	err = device_register(af_iucv_dev);
   	if (err)
-		goto out_driver;
+		goto out_iucv_dev;
   	return 0;
   
+out_iucv_dev:
+	kfree(af_iucv_dev);
   out_driver:
   	driver_unregister(&af_iucv_driver);
   out_iucv:

@@ -2496,6 +2498,7 @@ static void __exit afiucv_exit(void)
   {
   	if (pr_iucv) {
   		device_unregister(af_iucv_dev);
+		kfree(af_iucv_dev);
   		driver_unregister(&af_iucv_driver);
   		pr_iucv->iucv_unregister(&af_iucv_handler, 0);
   		symbol_put(iucv_if);  

No, you must not use kfree() after you called device_register() (even
if it was not successful!) -- see the comment for device_register().  

Yes, Your are right. First we need to call put_device() then kfree().
I will send updated patch.  

No, that's not correct, either. device_register() will give up any
reference it obtained, and the caller did not obtain any additional
reference, so a put_device() would be wrong. A kfree() on a refcounted
structure is wrong as well.  

If you will see the comment for device_register() (drivers/base/core.c)
there is mentioned that
'NOTE: _Never_ directly free @dev after calling this function, even
if it returned an error! Always use put_device() to give up the
reference initialized in this function instead.'
But as per you comment. we should not use.

You don't need to do a put_device() after your device_unregister(),
that's all managed by the driver core.