x25: Do not reference freed memory.

In x25_link_free(), we destroy 'nb' before dereferencing
'nb->dev'.  Don't do this, because 'nb' might be freed
by then.

Reported-by: Randy Dunlap <randy.dunlap@oracle.com>
Tested-by: Randy Dunlap <randy.dunlap@oracle.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 4 insertions, 1 deletions

diff --git a/net/x25/x25_link.c b/net/x25/x25_link.c
index 4cbc942f762a..21306928d47f 100644
--- a/net/x25/x25_link.c
+++ b/net/x25/x25_link.c
@@ -396,9 +396,12 @@ void __exit x25_link_free(void)
         write_lock_bh(&x25_neigh_list_lock);
 
         list_for_each_safe(entry, tmp, &x25_neigh_list) {
+                struct net_device *dev;
+
                 nb = list_entry(entry, struct x25_neigh, node);
+                dev = nb->dev;
                 __x25_remove_neigh(nb);
-                dev_put(nb->dev);
+                dev_put(dev);
         }
         write_unlock_bh(&x25_neigh_list_lock);
 }