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Commit f91ff5b9 authored by Eric Dumazet's avatar Eric Dumazet Committed by David S. Miller
Browse files

net: sk_{detach|attach}_filter() rcu fixes 



sk_attach_filter() and sk_detach_filter() are run with socket locked.

Use the appropriate rcu_dereference_protected() instead of blocking BH,
and rcu_dereference_bh().
There is no point adding BH prevention and memory barrier.

Signed-off-by: default avatarEric Dumazet <eric.dumazet@gmail.com>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
parent 7fa7cb71

net/core/filter.c

+4 −6
Original line number Diff line number Diff line
@@ -638,10 +638,9 @@ int sk_attach_filter(struct sock_fprog *fprog, struct sock *sk) 
		return err;

	}



	rcu_read_lock_bh();

	old_fp = rcu_dereference_bh(sk->sk_filter);

	old_fp = rcu_dereference_protected(sk->sk_filter,

					   sock_owned_by_user(sk));

	rcu_assign_pointer(sk->sk_filter, fp);

	rcu_read_unlock_bh();



	if (old_fp)

		sk_filter_delayed_uncharge(sk, old_fp);
@@ -654,14 +653,13 @@ int sk_detach_filter(struct sock *sk) 
	int ret = -ENOENT;

	struct sk_filter *filter;



	rcu_read_lock_bh();

	filter = rcu_dereference_bh(sk->sk_filter);

	filter = rcu_dereference_protected(sk->sk_filter,

					   sock_owned_by_user(sk));

	if (filter) {

		rcu_assign_pointer(sk->sk_filter, NULL);

		sk_filter_delayed_uncharge(sk, filter);

		ret = 0;

	}

	rcu_read_unlock_bh();

	return ret;

}

EXPORT_SYMBOL_GPL(sk_detach_filter);