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/tcp.c | |
| parent | 02614eee26fbdfd73b944769001cefeff6ed008c (diff) | |
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/tcp.c')
| -rw-r--r-- | net/ipv4/tcp.c | 8 |
1 files changed, 5 insertions, 3 deletions
diff --git a/net/ipv4/tcp.c b/net/ipv4/tcp.c index 71a956fbfc55..a12d81e01b3f 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; |