[PATCH net v3 2/2] ax25: Change kfree() in ax25_dev_free() to ax25_dev_put()

[Duoming Zhou]

The object "ax25_dev" is managed by reference counting. Thus it should
not be directly released by a kfree() call in ax25_dev_free(). Replace
it with a ax25_dev_put() call instead.

Fixes: d01ffb9eee4a ("ax25: add refcount in ax25_dev to avoid UAF bugs")
Suggested-by: Dan Carpenter <dan.carpenter@xxxxxxxxxx>
Signed-off-by: Duoming Zhou <duoming@xxxxxxxxxx>
---
Changes in v3:
  - Make commit messages more clearer.

 net/ax25/ax25_dev.c | 13 +++++--------
 1 file changed, 5 insertions(+), 8 deletions(-)

diff --git a/net/ax25/ax25_dev.c b/net/ax25/ax25_dev.c
index fbaaba0351e..8ee028e752f 100644
--- a/net/ax25/ax25_dev.c
+++ b/net/ax25/ax25_dev.c
@@ -188,16 +188,13 @@ struct net_device *ax25_fwd_dev(struct net_device *dev)
  */
 void __exit ax25_dev_free(void)
 {
-	ax25_dev *s, *ax25_dev;
+	ax25_dev *s, *n;
 
 	spin_lock_bh(&ax25_dev_lock);
-	ax25_dev = ax25_dev_list;
-	while (ax25_dev != NULL) {
-		s        = ax25_dev;
-		netdev_put(ax25_dev->dev, &ax25_dev->dev_tracker);
-		ax25_dev = ax25_dev->next;
-		kfree(s);
+	list_for_each_entry_safe(s, n, &ax25_dev_list, list) {
+		netdev_put(s->dev, &s->dev_tracker);
+		list_del(&s->list);
+		ax25_dev_put(s);
 	}
-	ax25_dev_list = NULL;
 	spin_unlock_bh(&ax25_dev_lock);
 }
-- 
2.17.1