Le mercredi 07 avril 2010 à 17:19 +0100, David Howells a écrit : > what is the value of sk->sk_wmem_alloc to the lock context of sk->sk_filter? > Why would lockdep be interested in sk_wmem_alloc? > > Surely, the assertion that the value of sk->sk_filter is related to > sk_wmem_alloc being 0 is independent of the need to dereference sk_filter for > RCU purposes. So why are these being combined? Because when sk->sk_filter is eventually written by some thread, this thread _must_ own a reference on the socket, that is sk_wmem_alloc > 0 So when reading sk->sk_filter, the general condition is : - We own the rcu lock - But on the particular case of __sk_free(), we owned the very last reference to sk (we are going to kfree it), so nobody can possibly change sk->sk_filter under us. -- To unsubscribe from this list: send the line "unsubscribe linux-nfs" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
