net: Move mutex_unlock() in cleanup_net() up

net_sem protects from pernet_list changing, while
ops_free_list() makes simple kfree(), and it can't
race with other pernet_operations callbacks.

So we may release net_mutex earlier then it was.

Signed-off-by: Kirill Tkhai <[email protected]>
Acked-by: Andrei Vagin <[email protected]>
Signed-off-by: David S. Miller <[email protected]>
(cherry picked from commit bcab1dd)
Orabug: 28900385
Signed-off-by: Nagarathnam Muthusamy <[email protected]>
Reviewed-by: Darren Kenny <[email protected]>

Author: Kirill Tkhai

net/core/net_namespace.c

@@ -488,11 +488,12 @@ static void cleanup_net(struct work_struct *work)
 	list_for_each_entry_reverse(ops, &pernet_list, list)
 		ops_exit_list(ops, &net_exit_list);
 
+	mutex_unlock(&net_mutex);
+
 	/* Free the net generic variables */
 	list_for_each_entry_reverse(ops, &pernet_list, list)
 		ops_free_list(ops, &net_exit_list);
 
-	mutex_unlock(&net_mutex);
 	up_read(&net_sem);
 
 	/* Ensure there are no outstanding rcu callbacks using this