From: Ying Xue Date: Thu, 26 Mar 2015 10:10:24 +0000 (+0800) Subject: tipc: involve reference counter for node structure X-Git-Tag: omap-for-v4.2/o2_dc~131^2~129^2 X-Git-Url: http://git.openpandora.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=8a0f6ebe8494;p=pandora-kernel.git tipc: involve reference counter for node structure 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: Erik Hugne Reviewed-by: Jon Maloy Signed-off-by: Ying Xue Signed-off-by: David S. Miller --- Reading git-diff-tree failed