tcp_get_timestamping_opt_stats() intentionally runs lockless, we must add READ_ONCE() annotations to keep KCSAN happy. WRITE_ONCE() annotations are already present. Fixes: e08ab0b377a1 ("tcp: add bytes not sent to SCM_TIMESTAMPING_OPT_STATS") Signed-off-by: Eric Dumazet --- net/ipv4/tcp.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) diff --git a/net/ipv4/tcp.c b/net/ipv4/tcp.c index 192e95b71ce9868980a809184be83398d8740427..68894c03f2622d1a08fd747ff4c5e32be8579d2c 100644 --- a/net/ipv4/tcp.c +++ b/net/ipv4/tcp.c @@ -4472,7 +4472,8 @@ struct sk_buff *tcp_get_timestamping_opt_stats(const struct sock *sk, nla_put_u16(stats, TCP_NLA_TIMEOUT_REHASH, READ_ONCE(tp->timeout_rehash)); nla_put_u32(stats, TCP_NLA_BYTES_NOTSENT, - max_t(int, 0, tp->write_seq - tp->snd_nxt)); + max_t(int, 0, + READ_ONCE(tp->write_seq) - READ_ONCE(tp->snd_nxt))); nla_put_u64_64bit(stats, TCP_NLA_EDT, orig_skb->skb_mstamp_ns, TCP_NLA_PAD); if (ack_skb) -- 2.54.0.rc1.513.gad8abe7a5a-goog