• Ying Xue's avatar
    tipc: involve reference counter for node structure · 8a0f6ebe
    Ying Xue authored
    TIPC node hash node table is protected with rcu lock on read side.
    tipc_node_find() is used to look for a node object with node address
    through iterating the hash node table. As the entire process of what
    tipc_node_find() traverses the table is guarded with rcu read lock,
    it's safe for us. However, when callers use the node object returned
    by tipc_node_find(), there is no rcu read lock applied. Therefore,
    this is absolutely unsafe for callers of tipc_node_find().
    Now we introduce a reference counter for node structure. Before
    tipc_node_find() returns node object to its caller, it first increases
    the reference counter. Accordingly, after its caller used it up,
    it decreases the counter again. This can prevent a node being used by
    one thread from being freed by another thread.
    Reviewed-by: default avatarErik Hugne <erik.hugne@ericsson.com>
    Reviewed-by: default avatarJon Maloy <jon.maloy@ericson.com>
    Signed-off-by: default avatarYing Xue <ying.xue@windriver.com>
    Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>