tcp: annotate a data-race around sysctl_tcp_wmem[0]

When reading wmem[0], it could be changed concurrently without
READ_ONCE() protection. So add one annotation here.

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

diff --git a/net/ipv4/tcp.c b/net/ipv4/tcp.c
index b091149742b1d0103e25981e940c17fae1b4d917..d20b62d521712ae7982b1e73fddf7d4be0df696d 100644 (file)
--- a/net/ipv4/tcp.c
+++ b/net/ipv4/tcp.c
@@ -975,7 +975,7 @@ int tcp_wmem_schedule(struct sock *sk, int copy)
         * Use whatever is left in sk->sk_forward_alloc and tcp_wmem[0]
         * to guarantee some progress.
         */
-       left = sock_net(sk)->ipv4.sysctl_tcp_wmem[0] - sk->sk_wmem_queued;
+       left = READ_ONCE(sock_net(sk)->ipv4.sysctl_tcp_wmem[0]) - sk->sk_wmem_queued;
        if (left > 0)
                sk_forced_mem_schedule(sk, min(left, copy));
        return min(copy, sk->sk_forward_alloc);