Merge tag 'asm-generic-4.6' of git://git.kernel.org/pub/scm/linux/kernel/git/arnd...

[deliverable/linux.git] / net / batman-adv / routing.c

diff --git a/net/batman-adv/routing.c b/net/batman-adv/routing.c
index 4dd646a52f1a16ca297a3cdb1abeff56206df166..b781bf75325061a5157c54bc976d1df1a522e0bd 100644 (file)
--- a/net/batman-adv/routing.c
+++ b/net/batman-adv/routing.c
@@ -105,6 +105,15 @@ static void _batadv_update_route(struct batadv_priv *bat_priv,
                neigh_node = NULL;
 
        spin_lock_bh(&orig_node->neigh_list_lock);
+       /* curr_router used earlier may not be the current orig_ifinfo->router
+        * anymore because it was dereferenced outside of the neigh_list_lock
+        * protected region. After the new best neighbor has replace the current
+        * best neighbor the reference counter needs to decrease. Consequently,
+        * the code needs to ensure the curr_router variable contains a pointer
+        * to the replaced best neighbor.
+        */
+       curr_router = rcu_dereference_protected(orig_ifinfo->router, true);
+
        rcu_assign_pointer(orig_ifinfo->router, neigh_node);
        spin_unlock_bh(&orig_node->neigh_list_lock);
        batadv_orig_ifinfo_put(orig_ifinfo);