net: sk_{detach|attach}_filter() rcu fixes (f91ff5b9) · Commits · 戴 / test

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:

Eric Dumazet <eric.dumazet@gmail.com> Signed-off-by:

David S. Miller <davem@davemloft.net>

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);

Admin message