tcp: annotate data-races around tp->window_clamp
[ Upstream commit f410cbea9f3d2675b4c8e52af1d1985b11b387d1 ] tp->window_clamp can be read locklessly, add READ_ONCE() and WRITE_ONCE() annotations. Signed-off-by: Eric Dumazet <edumazet@google.com> Reviewed-by: Jason Xing <kerneljasonxing@gmail.com> Link: https://lore.kernel.org/r/20240404114231.2195171-1-edumazet@google.com Signed-off-by: Jakub Kicinski <kuba@kernel.org> Stable-dep-of: 05f76b2d634e ("tcp: Adjust clamping window for applications specifying SO_RCVBUF") Signed-off-by: Sasha Levin <sashal@kernel.org>
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@ -424,7 +424,8 @@ struct sock *cookie_v4_check(struct sock *sk, struct sk_buff *skb)
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}
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/* Try to redo what tcp_v4_send_synack did. */
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req->rsk_window_clamp = tp->window_clamp ? :dst_metric(&rt->dst, RTAX_WINDOW);
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req->rsk_window_clamp = READ_ONCE(tp->window_clamp) ? :
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dst_metric(&rt->dst, RTAX_WINDOW);
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/* limit the window selection if the user enforce a smaller rx buffer */
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full_space = tcp_full_space(sk);
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if (sk->sk_userlocks & SOCK_RCVBUF_LOCK &&
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@ -1723,7 +1723,7 @@ int tcp_set_rcvlowat(struct sock *sk, int val)
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space = tcp_space_from_win(sk, val);
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if (space > sk->sk_rcvbuf) {
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WRITE_ONCE(sk->sk_rcvbuf, space);
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tcp_sk(sk)->window_clamp = val;
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WRITE_ONCE(tcp_sk(sk)->window_clamp, val);
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}
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return 0;
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}
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@ -3386,7 +3386,7 @@ int tcp_set_window_clamp(struct sock *sk, int val)
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if (!val) {
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if (sk->sk_state != TCP_CLOSE)
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return -EINVAL;
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tp->window_clamp = 0;
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WRITE_ONCE(tp->window_clamp, 0);
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} else {
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u32 new_rcv_ssthresh, old_window_clamp = tp->window_clamp;
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u32 new_window_clamp = val < SOCK_MIN_RCVBUF / 2 ?
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@ -3395,7 +3395,7 @@ int tcp_set_window_clamp(struct sock *sk, int val)
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if (new_window_clamp == old_window_clamp)
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return 0;
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tp->window_clamp = new_window_clamp;
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WRITE_ONCE(tp->window_clamp, new_window_clamp);
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if (new_window_clamp < old_window_clamp) {
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/* need to apply the reserved mem provisioning only
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* when shrinking the window clamp
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@ -4020,7 +4020,7 @@ int do_tcp_getsockopt(struct sock *sk, int level,
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TCP_RTO_MAX / HZ);
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break;
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case TCP_WINDOW_CLAMP:
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val = tp->window_clamp;
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val = READ_ONCE(tp->window_clamp);
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break;
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case TCP_INFO: {
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struct tcp_info info;
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@ -570,19 +570,20 @@ static void tcp_init_buffer_space(struct sock *sk)
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maxwin = tcp_full_space(sk);
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if (tp->window_clamp >= maxwin) {
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tp->window_clamp = maxwin;
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WRITE_ONCE(tp->window_clamp, maxwin);
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if (tcp_app_win && maxwin > 4 * tp->advmss)
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tp->window_clamp = max(maxwin -
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(maxwin >> tcp_app_win),
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4 * tp->advmss);
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WRITE_ONCE(tp->window_clamp,
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max(maxwin - (maxwin >> tcp_app_win),
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4 * tp->advmss));
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}
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/* Force reservation of one segment. */
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if (tcp_app_win &&
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tp->window_clamp > 2 * tp->advmss &&
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tp->window_clamp + tp->advmss > maxwin)
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tp->window_clamp = max(2 * tp->advmss, maxwin - tp->advmss);
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WRITE_ONCE(tp->window_clamp,
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max(2 * tp->advmss, maxwin - tp->advmss));
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tp->rcv_ssthresh = min(tp->rcv_ssthresh, tp->window_clamp);
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tp->snd_cwnd_stamp = tcp_jiffies32;
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@ -768,7 +769,8 @@ void tcp_rcv_space_adjust(struct sock *sk)
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WRITE_ONCE(sk->sk_rcvbuf, rcvbuf);
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/* Make the window clamp follow along. */
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tp->window_clamp = tcp_win_from_space(sk, rcvbuf);
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WRITE_ONCE(tp->window_clamp,
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tcp_win_from_space(sk, rcvbuf));
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}
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}
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tp->rcvq_space.space = copied;
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@ -6347,7 +6349,8 @@ consume:
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if (!tp->rx_opt.wscale_ok) {
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tp->rx_opt.snd_wscale = tp->rx_opt.rcv_wscale = 0;
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tp->window_clamp = min(tp->window_clamp, 65535U);
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WRITE_ONCE(tp->window_clamp,
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min(tp->window_clamp, 65535U));
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}
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if (tp->rx_opt.saw_tstamp) {
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@ -203,16 +203,17 @@ static inline void tcp_event_ack_sent(struct sock *sk, u32 rcv_nxt)
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* This MUST be enforced by all callers.
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*/
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void tcp_select_initial_window(const struct sock *sk, int __space, __u32 mss,
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__u32 *rcv_wnd, __u32 *window_clamp,
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__u32 *rcv_wnd, __u32 *__window_clamp,
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int wscale_ok, __u8 *rcv_wscale,
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__u32 init_rcv_wnd)
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{
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unsigned int space = (__space < 0 ? 0 : __space);
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u32 window_clamp = READ_ONCE(*__window_clamp);
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/* If no clamp set the clamp to the max possible scaled window */
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if (*window_clamp == 0)
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(*window_clamp) = (U16_MAX << TCP_MAX_WSCALE);
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space = min(*window_clamp, space);
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if (window_clamp == 0)
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window_clamp = (U16_MAX << TCP_MAX_WSCALE);
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space = min(window_clamp, space);
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/* Quantize space offering to a multiple of mss if possible. */
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if (space > mss)
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@ -239,12 +240,13 @@ void tcp_select_initial_window(const struct sock *sk, int __space, __u32 mss,
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/* Set window scaling on max possible window */
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space = max_t(u32, space, READ_ONCE(sock_net(sk)->ipv4.sysctl_tcp_rmem[2]));
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space = max_t(u32, space, READ_ONCE(sysctl_rmem_max));
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space = min_t(u32, space, *window_clamp);
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space = min_t(u32, space, window_clamp);
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*rcv_wscale = clamp_t(int, ilog2(space) - 15,
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0, TCP_MAX_WSCALE);
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}
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/* Set the clamp no higher than max representable value */
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(*window_clamp) = min_t(__u32, U16_MAX << (*rcv_wscale), *window_clamp);
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WRITE_ONCE(*__window_clamp,
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min_t(__u32, U16_MAX << (*rcv_wscale), window_clamp));
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}
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EXPORT_SYMBOL(tcp_select_initial_window);
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@ -3787,7 +3789,7 @@ static void tcp_connect_init(struct sock *sk)
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tcp_ca_dst_init(sk, dst);
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if (!tp->window_clamp)
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tp->window_clamp = dst_metric(dst, RTAX_WINDOW);
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WRITE_ONCE(tp->window_clamp, dst_metric(dst, RTAX_WINDOW));
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tp->advmss = tcp_mss_clamp(tp, dst_metric_advmss(dst));
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tcp_initialize_rcv_mss(sk);
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@ -3795,7 +3797,7 @@ static void tcp_connect_init(struct sock *sk)
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/* limit the window selection if the user enforce a smaller rx buffer */
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if (sk->sk_userlocks & SOCK_RCVBUF_LOCK &&
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(tp->window_clamp > tcp_full_space(sk) || tp->window_clamp == 0))
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tp->window_clamp = tcp_full_space(sk);
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WRITE_ONCE(tp->window_clamp, tcp_full_space(sk));
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rcv_wnd = tcp_rwnd_init_bpf(sk);
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if (rcv_wnd == 0)
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@ -243,7 +243,7 @@ struct sock *cookie_v6_check(struct sock *sk, struct sk_buff *skb)
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goto out_free;
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}
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req->rsk_window_clamp = tp->window_clamp ? :dst_metric(dst, RTAX_WINDOW);
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req->rsk_window_clamp = READ_ONCE(tp->window_clamp) ? :dst_metric(dst, RTAX_WINDOW);
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/* limit the window selection if the user enforce a smaller rx buffer */
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full_space = tcp_full_space(sk);
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if (sk->sk_userlocks & SOCK_RCVBUF_LOCK &&
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@ -2024,7 +2024,7 @@ static void mptcp_rcv_space_adjust(struct mptcp_sock *msk, int copied)
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ssk = mptcp_subflow_tcp_sock(subflow);
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slow = lock_sock_fast(ssk);
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WRITE_ONCE(ssk->sk_rcvbuf, rcvbuf);
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tcp_sk(ssk)->window_clamp = window_clamp;
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WRITE_ONCE(tcp_sk(ssk)->window_clamp, window_clamp);
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tcp_cleanup_rbuf(ssk, 1);
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unlock_sock_fast(ssk, slow);
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}
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@ -1564,7 +1564,7 @@ int mptcp_set_rcvlowat(struct sock *sk, int val)
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slow = lock_sock_fast(ssk);
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WRITE_ONCE(ssk->sk_rcvbuf, space);
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tcp_sk(ssk)->window_clamp = val;
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WRITE_ONCE(tcp_sk(ssk)->window_clamp, val);
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unlock_sock_fast(ssk, slow);
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}
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return 0;
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