batman-adv: fix global protection fault during soft_iface destruction

batadv_mesh_free() schedules some RCU callbacks which need the bat_priv struct to do their jobs, while free_netdev(), which is called immediately after, is destroying the private data. Put an rcu_barrier() in the middle so that free_netdev() is invoked only after all the callbacks returned. This bug has been introduced by ab8f433dd39be94e8617cff2dfe9f7eca162eb15 ("batman-adv: Move deinitialization of soft-interface to destructor") Signed-off-by: Antonio Quartulli <[email protected]> Signed-off-by: Marek Lindner <[email protected]> Signed-off-by: David S. Miller <[email protected]>
koalo · Apr 23, 2013 · 0c50134 · 0c50134
1 parent 6e0895c
commit 0c50134
Showing 1 changed file with 7 additions and 0 deletions.
diff --git a/net/batman-adv/soft-interface.c b/net/batman-adv/soft-interface.c
@@ -582,6 +582,13 @@ static void batadv_softif_free(struct net_device *dev)
 {
 	batadv_debugfs_del_meshif(dev);
 	batadv_mesh_free(dev);
+
+	/* some scheduled RCU callbacks need the bat_priv struct to accomplish
+	 * their tasks. Wait for them all to be finished before freeing the
+	 * netdev and its private data (bat_priv)
+	 */
+	rcu_barrier();
+
 	free_netdev(dev);
 }