af_unix: annotate lockless accesses to sk->sk_err

unix_poll() and unix_dgram_poll() read sk->sk_err
without any lock held.

Add relevant READ_ONCE()/WRITE_ONCE() annotations.

Signed-off-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

diff --git a/net/unix/af_unix.c b/net/unix/af_unix.c
index 0b0f18e..fb31e8a 100644 (file)
--- a/net/unix/af_unix.c
+++ b/net/unix/af_unix.c
@@ -557,7 +557,7 @@ static void unix_dgram_disconnected(struct sock *sk, struct sock *other)
                 * when peer was not connected to us.
                 */
                if (!sock_flag(other, SOCK_DEAD) && unix_peer(other) == sk) {
-                       other->sk_err = ECONNRESET;
+                       WRITE_ONCE(other->sk_err, ECONNRESET);
                        sk_error_report(other);
                }
        }
@@ -630,7 +630,7 @@ static void unix_release_sock(struct sock *sk, int embrion)
                        /* No more writes */
                        skpair->sk_shutdown = SHUTDOWN_MASK;
                        if (!skb_queue_empty(&sk->sk_receive_queue) || embrion)
-                               skpair->sk_err = ECONNRESET;
+                               WRITE_ONCE(skpair->sk_err, ECONNRESET);
                        unix_state_unlock(skpair);
                        skpair->sk_state_change(skpair);
                        sk_wake_async(skpair, SOCK_WAKE_WAITD, POLL_HUP);
@@ -3165,7 +3165,7 @@ static __poll_t unix_poll(struct file *file, struct socket *sock, poll_table *wa
        mask = 0;
 
        /* exceptional events? */
-       if (sk->sk_err)
+       if (READ_ONCE(sk->sk_err))
                mask |= EPOLLERR;
        if (sk->sk_shutdown == SHUTDOWN_MASK)
                mask |= EPOLLHUP;
@@ -3208,7 +3208,8 @@ static __poll_t unix_dgram_poll(struct file *file, struct socket *sock,
        mask = 0;
 
        /* exceptional events? */
-       if (sk->sk_err || !skb_queue_empty_lockless(&sk->sk_error_queue))
+       if (READ_ONCE(sk->sk_err) ||
+           !skb_queue_empty_lockless(&sk->sk_error_queue))
                mask |= EPOLLERR |
                        (sock_flag(sk, SOCK_SELECT_ERR_QUEUE) ? EPOLLPRI : 0);