tcp_get_timestamping_opt_stats() intentionally runs lockless, we must add READ_ONCE() and WRITE_ONCE() annotations to keep KCSAN happy. Fixes: 87ecc95d81d9 ("tcp: add send queue size stat in SCM_TIMESTAMPING_OPT_STATS") Signed-off-by: Eric Dumazet --- net/ipv4/tcp.c | 4 +++- net/ipv4/tcp_input.c | 4 ++-- net/ipv4/tcp_output.c | 2 +- 3 files changed, 6 insertions(+), 4 deletions(-) diff --git a/net/ipv4/tcp.c b/net/ipv4/tcp.c index 0aabd02d44967dae3e569702f76037beb45e5de8..729936d13a5c6d9c39edc880636e01cf0973688e 100644 --- a/net/ipv4/tcp.c +++ b/net/ipv4/tcp.c @@ -4456,7 +4456,9 @@ struct sk_buff *tcp_get_timestamping_opt_stats(const struct sock *sk, nla_put_u32(stats, TCP_NLA_DELIVERED, READ_ONCE(tp->delivered)); nla_put_u32(stats, TCP_NLA_DELIVERED_CE, READ_ONCE(tp->delivered_ce)); - nla_put_u32(stats, TCP_NLA_SNDQ_SIZE, tp->write_seq - tp->snd_una); + nla_put_u32(stats, TCP_NLA_SNDQ_SIZE, + max_t(int, 0, + READ_ONCE(tp->write_seq) - READ_ONCE(tp->snd_una))); nla_put_u8(stats, TCP_NLA_CA_STATE, inet_csk(sk)->icsk_ca_state); nla_put_u64_64bit(stats, TCP_NLA_BYTES_SENT, tp->bytes_sent, diff --git a/net/ipv4/tcp_input.c b/net/ipv4/tcp_input.c index 63ff89210a72fbf5710279c41010d3f6e734e522..edb5013873e0c4a9ba2f8a81a43eff5fb6e7a47b 100644 --- a/net/ipv4/tcp_input.c +++ b/net/ipv4/tcp_input.c @@ -3912,7 +3912,7 @@ static void tcp_snd_una_update(struct tcp_sock *tp, u32 ack) sock_owned_by_me((struct sock *)tp); tp->bytes_acked += delta; tcp_snd_sne_update(tp, ack); - tp->snd_una = ack; + WRITE_ONCE(tp->snd_una, ack); } static void tcp_rcv_sne_update(struct tcp_sock *tp, u32 seq) @@ -7240,7 +7240,7 @@ tcp_rcv_state_process(struct sock *sk, struct sk_buff *skb) if (sk->sk_socket) sk_wake_async(sk, SOCK_WAKE_IO, POLL_OUT); - tp->snd_una = TCP_SKB_CB(skb)->ack_seq; + WRITE_ONCE(tp->snd_una, TCP_SKB_CB(skb)->ack_seq); tp->snd_wnd = ntohs(th->window) << tp->rx_opt.snd_wscale; tcp_init_wl(tp, TCP_SKB_CB(skb)->seq); diff --git a/net/ipv4/tcp_output.c b/net/ipv4/tcp_output.c index 2663505a0dd7a0eae69f6a91250b4a0b6f357f7d..9f83c7e4acabc64f0a45e4879c326694a306b368 100644 --- a/net/ipv4/tcp_output.c +++ b/net/ipv4/tcp_output.c @@ -4153,7 +4153,7 @@ static void tcp_connect_init(struct sock *sk) tp->snd_wnd = 0; tcp_init_wl(tp, 0); tcp_write_queue_purge(sk); - tp->snd_una = tp->write_seq; + WRITE_ONCE(tp->snd_una, tp->write_seq); tp->snd_sml = tp->write_seq; tp->snd_up = tp->write_seq; WRITE_ONCE(tp->snd_nxt, tp->write_seq); -- 2.54.0.rc1.513.gad8abe7a5a-goog