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[108.212.132.20]) by smtp.gmail.com with ESMTPSA id 46e09a7af769-7d7449b9e57sm3928395a34.22.2026.03.09.18.26.47 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Mon, 09 Mar 2026 18:26:48 -0700 (PDT) From: Wesley Atwell To: edumazet@google.com, ncardwell@google.com, davem@davemloft.net, dsahern@kernel.org, kuba@kernel.org, pabeni@redhat.com Cc: kuniyu@google.com, horms@kernel.org, netdev@vger.kernel.org, linux-kernel@vger.kernel.org, Wesley Atwell Subject: [PATCH] tcp: use WRITE_ONCE() for tsoffset in tcp_v6_connect() Date: Mon, 9 Mar 2026 19:26:04 -0600 Message-Id: <20260310012604.145661-1-atwellwea@gmail.com> X-Mailer: git-send-email 2.34.1 Precedence: bulk X-Mailing-List: netdev@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Commit dd23c9f1e8d5 ("tcp: annotate data-races around tp->tsoffset") updated do_tcp_getsockopt() to read tp->tsoffset with READ_ONCE() for TCP_TIMESTAMP because another CPU may change it concurrently. tcp_v6_connect() still stores tp->tsoffset with a plain write. That store runs under lock_sock() via inet_stream_connect(), but the socket lock does not serialize a concurrent getsockopt(TCP_TIMESTAMP) from another task sharing the socket. Use WRITE_ONCE() for the tcp_v6_connect() store so the connect-time writer matches the lockless TCP_TIMESTAMP reader. This also makes the IPv6 path consistent with tcp_v4_connect(). Signed-off-by: Wesley Atwell --- net/ipv6/tcp_ipv6.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/net/ipv6/tcp_ipv6.c b/net/ipv6/tcp_ipv6.c index bb09d5ccf599..ba7cd7d3d4da 100644 --- a/net/ipv6/tcp_ipv6.c +++ b/net/ipv6/tcp_ipv6.c @@ -325,7 +325,7 @@ static int tcp_v6_connect(struct sock *sk, struct sockaddr_unsized *uaddr, inet->inet_dport); if (!tp->write_seq) WRITE_ONCE(tp->write_seq, st.seq); - tp->tsoffset = st.ts_off; + WRITE_ONCE(tp->tsoffset, st.ts_off); } if (tcp_fastopen_defer_connect(sk, &err)) -- 2.34.1