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Commit b5dcbad2 authored by Sven Eckelmann's avatar Sven Eckelmann Committed by Simon Wunderlich
Browse files

batman-adv: Fix consistency of update route messages 



The debug messages of _batadv_update_route were printed before the actual
route change is done. At this point it is not really known which
curr_router will be replaced. Thus the messages could print the wrong
operation.

Printing the debug messages after the operation was done avoids this
problem.

Signed-off-by: default avatarSven Eckelmann <sven@narfation.org>
Signed-off-by: default avatarMarek Lindner <mareklindner@neomailbox.ch>
Signed-off-by: default avatarSimon Wunderlich <sw@simonwunderlich.de>
parent 4d7de48c

net/batman-adv/routing.c

+17 −26
Original line number Diff line number Diff line
@@ -74,11 +74,23 @@ static void _batadv_update_route(struct batadv_priv *bat_priv, 
	if (!orig_ifinfo)

		return;



	rcu_read_lock();

	curr_router = rcu_dereference(orig_ifinfo->router);

	if (curr_router && !kref_get_unless_zero(&curr_router->refcount))

		curr_router = NULL;

	rcu_read_unlock();

	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);



	/* increase refcount of new best neighbor */

	if (neigh_node)

		kref_get(&neigh_node->refcount);



	rcu_assign_pointer(orig_ifinfo->router, neigh_node);

	spin_unlock_bh(&orig_node->neigh_list_lock);

	batadv_orig_ifinfo_put(orig_ifinfo);



	/* route deleted */

	if ((curr_router) && (!neigh_node)) {
@@ -100,27 +112,6 @@ static void _batadv_update_route(struct batadv_priv *bat_priv, 
			   curr_router->addr);

	}



	if (curr_router)

		batadv_neigh_node_put(curr_router);



	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);



	/* increase refcount of new best neighbor */

	if (neigh_node)

		kref_get(&neigh_node->refcount);



	rcu_assign_pointer(orig_ifinfo->router, neigh_node);

	spin_unlock_bh(&orig_node->neigh_list_lock);

	batadv_orig_ifinfo_put(orig_ifinfo);



	/* decrease refcount of previous best neighbor */

	if (curr_router)

		batadv_neigh_node_put(curr_router);