From: Eric Dumazet Date: Thu, 16 Apr 2026 20:03:17 +0000 (+0000) Subject: tcp: annotate data-races around tp->timeout_rehash X-Git-Tag: v7.1-rc1~36^2~60^2~2 X-Git-Url: http://git.ipfire.org/gitweb/?a=commitdiff_plain;h=71c675358b711bbfd8528949249419dc2dfa4ce1;p=thirdparty%2Fkernel%2Flinux.git tcp: annotate data-races around tp->timeout_rehash tcp_get_timestamping_opt_stats() intentionally runs lockless, we must add READ_ONCE() and WRITE_ONCE() annotations to keep KCSAN happy. Fixes: 32efcc06d2a1 ("tcp: export count for rehash attempts") Signed-off-by: Eric Dumazet Link: https://patch.msgid.link/20260416200319.3608680-13-edumazet@google.com Signed-off-by: Jakub Kicinski --- diff --git a/net/ipv4/tcp.c b/net/ipv4/tcp.c index 541bd0d2d8c4..192e95b71ce9 100644 --- a/net/ipv4/tcp.c +++ b/net/ipv4/tcp.c @@ -4469,7 +4469,8 @@ struct sk_buff *tcp_get_timestamping_opt_stats(const struct sock *sk, nla_put_u32(stats, TCP_NLA_DSACK_DUPS, READ_ONCE(tp->dsack_dups)); nla_put_u32(stats, TCP_NLA_REORD_SEEN, READ_ONCE(tp->reord_seen)); nla_put_u32(stats, TCP_NLA_SRTT, READ_ONCE(tp->srtt_us) >> 3); - nla_put_u16(stats, TCP_NLA_TIMEOUT_REHASH, tp->timeout_rehash); + 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)); nla_put_u64_64bit(stats, TCP_NLA_EDT, orig_skb->skb_mstamp_ns, diff --git a/net/ipv4/tcp_timer.c b/net/ipv4/tcp_timer.c index ea99988795e7..8d791a954cd6 100644 --- a/net/ipv4/tcp_timer.c +++ b/net/ipv4/tcp_timer.c @@ -297,7 +297,7 @@ static int tcp_write_timeout(struct sock *sk) } if (sk_rethink_txhash(sk)) { - tp->timeout_rehash++; + WRITE_ONCE(tp->timeout_rehash, tp->timeout_rehash + 1); __NET_INC_STATS(sock_net(sk), LINUX_MIB_TCPTIMEOUTREHASH); }