batman-adv: Correct rcu refcounting for gw_node
It might be possible that 2 threads access the same data in the same
rcu grace period. The first thread calls call_rcu() to decrement the
refcount and free the data while the second thread increases the
refcount to use the data. To avoid this race condition all refcount
operations have to be atomic.
Reported-by: Sven Eckelmann <sven@narfation.org>
Signed-off-by: Marek Lindner <lindner_marek@yahoo.de>
diff --git a/net/batman-adv/types.h b/net/batman-adv/types.h
index 084604a..cfbeb45 100644
--- a/net/batman-adv/types.h
+++ b/net/batman-adv/types.h
@@ -98,7 +98,7 @@
struct hlist_node list;
struct orig_node *orig_node;
unsigned long deleted;
- struct kref refcount;
+ atomic_t refcount;
struct rcu_head rcu;
};