diff options
| author | Eric Dumazet <edumazet@google.com> | 2025-08-21 14:19:00 +0000 |
|---|---|---|
| committer | Jakub Kicinski <kuba@kernel.org> | 2025-08-22 15:58:58 -0700 |
| commit | d5ffba0f254d29a13908d4510762b31d4247a94c (patch) | |
| tree | 96296c80cf3643f72f2a2d84751758af22bc2db7 /net/ipv4 | |
| parent | 02614eee26fbdfd73b944769001cefeff6ed008c (diff) | |
| download | tip-d5ffba0f254d29a13908d4510762b31d4247a94c.tar.gz | |
tcp: annotate data-races around tp->rx_opt.user_mss
This field is already read locklessly for listeners,
next patch will make setsockopt(TCP_MAXSEG) lockless.
Signed-off-by: Eric Dumazet <edumazet@google.com>
Reviewed-by: Neal Cardwell <ncardwell@google.com>
Link: https://patch.msgid.link/20250821141901.18839-2-edumazet@google.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Diffstat (limited to 'net/ipv4')
| -rw-r--r-- | net/ipv4/tcp.c | 8 | ||||
| -rw-r--r-- | net/ipv4/tcp_input.c | 8 | ||||
| -rw-r--r-- | net/ipv4/tcp_output.c | 6 |
3 files changed, 13 insertions, 9 deletions
diff --git a/net/ipv4/tcp.c b/net/ipv4/tcp.c index 71a956fbfc5533..a12d81e01b3f2f 100644 --- a/net/ipv4/tcp.c +++ b/net/ipv4/tcp.c @@ -3760,7 +3760,7 @@ int tcp_sock_set_maxseg(struct sock *sk, int val) if (val && (val < TCP_MIN_MSS || val > MAX_TCP_WINDOW)) return -EINVAL; - tcp_sk(sk)->rx_opt.user_mss = val; + WRITE_ONCE(tcp_sk(sk)->rx_opt.user_mss, val); return 0; } @@ -4383,6 +4383,7 @@ int do_tcp_getsockopt(struct sock *sk, int level, struct inet_connection_sock *icsk = inet_csk(sk); struct tcp_sock *tp = tcp_sk(sk); struct net *net = sock_net(sk); + int user_mss; int val, len; if (copy_from_sockptr(&len, optlen, sizeof(int))) @@ -4396,9 +4397,10 @@ int do_tcp_getsockopt(struct sock *sk, int level, switch (optname) { case TCP_MAXSEG: val = tp->mss_cache; - if (tp->rx_opt.user_mss && + user_mss = READ_ONCE(tp->rx_opt.user_mss); + if (user_mss && ((1 << sk->sk_state) & (TCPF_CLOSE | TCPF_LISTEN))) - val = tp->rx_opt.user_mss; + val = user_mss; if (tp->repair) val = tp->rx_opt.mss_clamp; break; diff --git a/net/ipv4/tcp_input.c b/net/ipv4/tcp_input.c index 71b76e98371a66..7b537978dfe6b4 100644 --- a/net/ipv4/tcp_input.c +++ b/net/ipv4/tcp_input.c @@ -6297,7 +6297,7 @@ static bool tcp_rcv_fastopen_synack(struct sock *sk, struct sk_buff *synack, u16 mss = tp->rx_opt.mss_clamp, try_exp = 0; bool syn_drop = false; - if (mss == tp->rx_opt.user_mss) { + if (mss == READ_ONCE(tp->rx_opt.user_mss)) { struct tcp_options_received opt; /* Get original SYNACK MSS value if user MSS sets mss_clamp */ @@ -7117,7 +7117,7 @@ u16 tcp_get_syncookie_mss(struct request_sock_ops *rsk_ops, return 0; } - mss = tcp_parse_mss_option(th, tp->rx_opt.user_mss); + mss = tcp_parse_mss_option(th, READ_ONCE(tp->rx_opt.user_mss)); if (!mss) mss = af_ops->mss_clamp; @@ -7131,7 +7131,7 @@ int tcp_conn_request(struct request_sock_ops *rsk_ops, { struct tcp_fastopen_cookie foc = { .len = -1 }; struct tcp_options_received tmp_opt; - struct tcp_sock *tp = tcp_sk(sk); + const struct tcp_sock *tp = tcp_sk(sk); struct net *net = sock_net(sk); struct sock *fastopen_sk = NULL; struct request_sock *req; @@ -7182,7 +7182,7 @@ int tcp_conn_request(struct request_sock_ops *rsk_ops, tcp_clear_options(&tmp_opt); tmp_opt.mss_clamp = af_ops->mss_clamp; - tmp_opt.user_mss = tp->rx_opt.user_mss; + tmp_opt.user_mss = READ_ONCE(tp->rx_opt.user_mss); tcp_parse_options(sock_net(sk), skb, &tmp_opt, 0, want_cookie ? NULL : &foc); diff --git a/net/ipv4/tcp_output.c b/net/ipv4/tcp_output.c index dfbac0876d96ee..86892c8672ed49 100644 --- a/net/ipv4/tcp_output.c +++ b/net/ipv4/tcp_output.c @@ -3890,6 +3890,7 @@ static void tcp_connect_init(struct sock *sk) const struct dst_entry *dst = __sk_dst_get(sk); struct tcp_sock *tp = tcp_sk(sk); __u8 rcv_wscale; + u16 user_mss; u32 rcv_wnd; /* We'll fix this up when we get a response from the other end. @@ -3902,8 +3903,9 @@ static void tcp_connect_init(struct sock *sk) tcp_ao_connect_init(sk); /* If user gave his TCP_MAXSEG, record it to clamp */ - if (tp->rx_opt.user_mss) - tp->rx_opt.mss_clamp = tp->rx_opt.user_mss; + user_mss = READ_ONCE(tp->rx_opt.user_mss); + if (user_mss) + tp->rx_opt.mss_clamp = user_mss; tp->max_window = 0; tcp_mtup_init(sk); tcp_sync_mss(sk, dst_mtu(dst)); |