tcp: annotate data-races around icsk->icsk_user_timeout

This field can be read locklessly from do_tcp_getsockopt()

Fixes: dca43c75e7e5 ("tcp: Add TCP_USER_TIMEOUT socket option.")
Signed-off-by: Eric Dumazet <edumazet@google.com>
Link: https://lore.kernel.org/r/20230719212857.3943972-11-edumazet@google.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

diff --git a/net/ipv4/tcp.c b/net/ipv4/tcp.c
index 2b2241e9b492726562a6b5055cf8c168e5fed799..3e137e9a18f552a02d8c74e1af34ba2356e4d8ed 100644 (file)
--- a/net/ipv4/tcp.c
+++ b/net/ipv4/tcp.c
@@ -3300,7 +3300,7 @@ EXPORT_SYMBOL(tcp_sock_set_syncnt);
 void tcp_sock_set_user_timeout(struct sock *sk, u32 val)
 {
        lock_sock(sk);
-       inet_csk(sk)->icsk_user_timeout = val;
+       WRITE_ONCE(inet_csk(sk)->icsk_user_timeout, val);
        release_sock(sk);
 }
 EXPORT_SYMBOL(tcp_sock_set_user_timeout);
@@ -3620,7 +3620,7 @@ int do_tcp_setsockopt(struct sock *sk, int level, int optname,
                if (val < 0)
                        err = -EINVAL;
                else
-                       icsk->icsk_user_timeout = val;
+                       WRITE_ONCE(icsk->icsk_user_timeout, val);
                break;
 
        case TCP_FASTOPEN:
@@ -4141,7 +4141,7 @@ int do_tcp_getsockopt(struct sock *sk, int level,
                break;
 
        case TCP_USER_TIMEOUT:
-               val = icsk->icsk_user_timeout;
+               val = READ_ONCE(icsk->icsk_user_timeout);
                break;
 
        case TCP_FASTOPEN: