From: Eric Dumazet Date: Fri, 22 Aug 2025 09:17:25 +0000 (+0000) Subject: tcp: annotate data-races around icsk->icsk_retransmits X-Git-Url: https://www.infradead.org/git/?a=commitdiff_plain;h=e6f178be3c12cd6b8fb1b81dd0b9118e0a0d0333;p=users%2Fhch%2Fmisc.git tcp: annotate data-races around icsk->icsk_retransmits icsk->icsk_retransmits is read locklessly from inet_sk_diag_fill(), tcp_get_timestamping_opt_stats, get_tcp4_sock() and get_tcp6_sock(). Add corresponding READ_ONCE()/WRITE_ONCE() annotations. Signed-off-by: Eric Dumazet Reviewed-by: Neal Cardwell Link: https://patch.msgid.link/20250822091727.835869-2-edumazet@google.com Signed-off-by: Jakub Kicinski --- diff --git a/net/ipv4/inet_diag.c b/net/ipv4/inet_diag.c index 2fa53b16fe77..35c1579e5bd4 100644 --- a/net/ipv4/inet_diag.c +++ b/net/ipv4/inet_diag.c @@ -313,7 +313,7 @@ int inet_sk_diag_fill(struct sock *sk, struct inet_connection_sock *icsk, icsk_pending == ICSK_TIME_REO_TIMEOUT || icsk_pending == ICSK_TIME_LOSS_PROBE) { r->idiag_timer = 1; - r->idiag_retrans = icsk->icsk_retransmits; + r->idiag_retrans = READ_ONCE(icsk->icsk_retransmits); r->idiag_expires = jiffies_delta_to_msecs(icsk_timeout(icsk) - jiffies); } else if (icsk_pending == ICSK_TIME_PROBE0) { diff --git a/net/ipv4/tcp.c b/net/ipv4/tcp.c index 99232903b03c..4728801d06a7 100644 --- a/net/ipv4/tcp.c +++ b/net/ipv4/tcp.c @@ -4346,7 +4346,8 @@ struct sk_buff *tcp_get_timestamping_opt_stats(const struct sock *sk, nla_put_u32(stats, TCP_NLA_REORDERING, tp->reordering); nla_put_u32(stats, TCP_NLA_MIN_RTT, tcp_min_rtt(tp)); - nla_put_u8(stats, TCP_NLA_RECUR_RETRANS, inet_csk(sk)->icsk_retransmits); + nla_put_u8(stats, TCP_NLA_RECUR_RETRANS, + READ_ONCE(inet_csk(sk)->icsk_retransmits)); nla_put_u8(stats, TCP_NLA_DELIVERY_RATE_APP_LMT, !!tp->rate_app_limited); nla_put_u32(stats, TCP_NLA_SND_SSTHRESH, tp->snd_ssthresh); nla_put_u32(stats, TCP_NLA_DELIVERED, tp->delivered); diff --git a/net/ipv4/tcp_input.c b/net/ipv4/tcp_input.c index 7b537978dfe6..3baf3bef0d83 100644 --- a/net/ipv4/tcp_input.c +++ b/net/ipv4/tcp_input.c @@ -2569,7 +2569,7 @@ static bool tcp_try_undo_loss(struct sock *sk, bool frto_undo) if (frto_undo) NET_INC_STATS(sock_net(sk), LINUX_MIB_TCPSPURIOUSRTOS); - inet_csk(sk)->icsk_retransmits = 0; + WRITE_ONCE(inet_csk(sk)->icsk_retransmits, 0); if (tcp_is_non_sack_preventing_reopen(sk)) return true; if (frto_undo || tcp_is_sack(tp)) { @@ -3851,7 +3851,7 @@ static int tcp_ack(struct sock *sk, const struct sk_buff *skb, int flag) if (after(ack, prior_snd_una)) { flag |= FLAG_SND_UNA_ADVANCED; - icsk->icsk_retransmits = 0; + WRITE_ONCE(icsk->icsk_retransmits, 0); #if IS_ENABLED(CONFIG_TLS_DEVICE) if (static_branch_unlikely(&clean_acked_data_enabled.key)) @@ -6636,7 +6636,7 @@ static void tcp_rcv_synrecv_state_fastopen(struct sock *sk) tcp_try_undo_recovery(sk); tcp_update_rto_time(tp); - inet_csk(sk)->icsk_retransmits = 0; + WRITE_ONCE(inet_csk(sk)->icsk_retransmits, 0); /* In tcp_fastopen_synack_timer() on the first SYNACK RTO we set * retrans_stamp but don't enter CA_Loss, so in case that happened we * need to zero retrans_stamp here to prevent spurious diff --git a/net/ipv4/tcp_ipv4.c b/net/ipv4/tcp_ipv4.c index 84d3d556ed80..5d549dfd4e60 100644 --- a/net/ipv4/tcp_ipv4.c +++ b/net/ipv4/tcp_ipv4.c @@ -2958,7 +2958,7 @@ static void get_tcp4_sock(struct sock *sk, struct seq_file *f, int i) rx_queue, timer_active, jiffies_delta_to_clock_t(timer_expires - jiffies), - icsk->icsk_retransmits, + READ_ONCE(icsk->icsk_retransmits), from_kuid_munged(seq_user_ns(f), sk_uid(sk)), icsk->icsk_probes_out, sock_i_ino(sk), diff --git a/net/ipv4/tcp_output.c b/net/ipv4/tcp_output.c index 86892c8672ed..72969c27eaaa 100644 --- a/net/ipv4/tcp_output.c +++ b/net/ipv4/tcp_output.c @@ -3956,7 +3956,7 @@ static void tcp_connect_init(struct sock *sk) WRITE_ONCE(tp->copied_seq, tp->rcv_nxt); inet_csk(sk)->icsk_rto = tcp_timeout_init(sk); - inet_csk(sk)->icsk_retransmits = 0; + WRITE_ONCE(inet_csk(sk)->icsk_retransmits, 0); tcp_clear_retrans(tp); } diff --git a/net/ipv4/tcp_timer.c b/net/ipv4/tcp_timer.c index a207877270fb..8b11ab4cc952 100644 --- a/net/ipv4/tcp_timer.c +++ b/net/ipv4/tcp_timer.c @@ -444,7 +444,7 @@ static void tcp_update_rto_stats(struct sock *sk) tp->total_rto_recoveries++; tp->rto_stamp = tcp_time_stamp_ms(tp); } - icsk->icsk_retransmits++; + WRITE_ONCE(icsk->icsk_retransmits, icsk->icsk_retransmits + 1); tp->total_rto++; } diff --git a/net/ipv6/tcp_ipv6.c b/net/ipv6/tcp_ipv6.c index 7577e7eb2c97..7b177054452b 100644 --- a/net/ipv6/tcp_ipv6.c +++ b/net/ipv6/tcp_ipv6.c @@ -2230,7 +2230,7 @@ static void get_tcp6_sock(struct seq_file *seq, struct sock *sp, int i) rx_queue, timer_active, jiffies_delta_to_clock_t(timer_expires - jiffies), - icsk->icsk_retransmits, + READ_ONCE(icsk->icsk_retransmits), from_kuid_munged(seq_user_ns(seq), sk_uid(sp)), icsk->icsk_probes_out, sock_i_ino(sp), diff --git a/net/mptcp/protocol.c b/net/mptcp/protocol.c index 9a287b75c1b3..f2e728239480 100644 --- a/net/mptcp/protocol.c +++ b/net/mptcp/protocol.c @@ -2587,7 +2587,8 @@ static void __mptcp_retrans(struct sock *sk) if (mptcp_data_fin_enabled(msk)) { struct inet_connection_sock *icsk = inet_csk(sk); - icsk->icsk_retransmits++; + WRITE_ONCE(icsk->icsk_retransmits, + icsk->icsk_retransmits + 1); mptcp_set_datafin_timeout(sk); mptcp_send_ack(msk);