tipc: eliminate risk of finding to-be-deleted node instance
Although we have never seen it happen, we have identified the following problematic scenario when nodes are stopped and deleted: CPU0: CPU1: tipc_node_xxx() //ref == 1 tipc_node_put() //ref -> 0 tipc_node_find() // node still in table tipc_node_delete() list_del_rcu(n. list) tipc_node_get() //ref -> 1, bad kfree_rcu() tipc_node_put() //ref to 0 again. kfree_rcu() // BOOM! We fix this by introducing use of the conditional kref_get_if_not_zero() instead of kref_get() in the function tipc_node_find(). This eliminates any risk of post-mortem access. Reported-by:Zhijiang Hu <huzhijiang@gmail.com> Acked-by:
Ying Xue <ying.xue@windriver.com> Signed-off-by:
Jon Maloy <jon.maloy@ericsson.com> Signed-off-by:
David S. Miller <davem@davemloft.net>
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3da7611f
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