From mboxrd@z Thu Jan 1 00:00:00 1970 Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.remote-ip=91.218.175.160 ARC-Seal: i=1; d=subspace.kernel.org; s=arc20261015; a=rsa-sha256; cv=none; t=1794193098; b=jGIpMSf1Hbcetj/wIXyTbiBiRRh8OXdhj5E/+jseIATiOP0+RI8saiHsFv5XjCaIJu9S LqvEY9JOHw7uaasRIK+hf8YC5fAQdd8dZK5CIdnmb0QbWKXhlumxkgjmuX33yHkEW4L1R n3DqrPKG02E42bgWJEKiFnWDDYJ47nTeU5fW7B8MqnUTA0AaT0F+1YNM0hAY7i19Sa9Hi K638Mmdc90AQpvNwghxDOby5CCskoWOUd3bF7cQia3Snu/EivavN6q2G/JeapRF2z8Pmb ei4TEWST4WbBHLSX0mUqFgHnujpkRzYNsYmpqv1ASjH0HQWzTHeRzasEOOpnIpjvMQw== ARC-Message-Signature: i=1; d=subspace.kernel.org; s=arc20261015; a=rsa-sha256; c=relaxed/relaxed; t=1794193098; h=DMARC-Filter:X-Envelope-To:DKIM-Signature:X-Envelope-To:Received: X-Mizu-Trace-ID:X-Migadu-Flow:From:To:Cc:Subject:Date:Message-ID: X-Mailer:In-Reply-To:References:MIME-Version: Content-Transfer-Encoding; bh=/ZzxlcdhJK/ud/KyVxq+93rWFaFImo0MKgWgyLOhJCY=; b=gyjPBv+dCKOS0Et80uGKLr7YfLIi+0gs9cWtYkOfgNqW9cDQIodXBssMDcIg2an9Tl+v lmFoPYevr83+CahdSvGIgAeZ2IDL1cYqRhZ+DgWiRN3aKwIpRUokIeA4ELxg8IORuOXmT 4ySsqiX85LXpAvEQeAWWK29XyNUz9lGh+Q0Hx/NU/9b/9a411pAwYXOFRymz7Sg/5+BX6 5Yb+0T5uhU2DLhWUXLXEjl5ucC5J8DFyA/kinTabbTYZfUoARBgZ6NQi1WeWQlEYyJ9eo pNMRFPBtPHIeaSMXxLW4IaARFtCK1MA88C8WlJsxjeI7Uz/YsO1YR1x9x5rt2XcEE5g== ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dmarc=pass header.from=linux.dev; spf=pass smtp.mailfrom=linux.dev; dkim=pass header.d=linux.dev header.i=@linux.dev header.a=rsa-sha256 header.s=key1 header.b=ZwZturDY; arc=none smtp.remote-ip=91.218.175.160 Received: from mta0.migadu.com (out-160.mta0.migadu.com [91.218.175.160]) (using TLSv1.3 with cipher TLS_AES_128_GCM_SHA256 (128/128 bits) key-exchange X25519 server-signature ECDSA (prime256v1) server-digest SHA256) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 2F95D606A325 for ; Mon, 9 Nov 2026 02:58:17 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.4.2 smtp.subspace.kernel.org 2F95D606A325 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=linux.dev Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=linux.dev Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key, unprotected) header.d=linux.dev header.i=@linux.dev header.a=rsa-sha256 header.s=key1 header.b=ZwZturDY X-Envelope-To: linux-kernel@vger.kernel.org DKIM-Signature: a=rsa-sha256; bh=VW2UPIRvdm02fMitf8vcWNrGIl0DKTRZ6TxDmEcEySs=; c=simple/simple; d=linux.dev; h=from:to:subject:date:message-id:mime-version:content-type; s=key1; t=1794193096; v=1; x=1794797896; b=ZwZturDYVJV0ijfMY4q1v+YvPkjzx4ykHjEuDzRYuFWI4wl9s+G6Izqovag1beThw64sqt4S Fu5nA8Gvk2cCe1ih31TvDCiyhP+wAhuqoUrxEQ7ASoBnLZ4vGk0WKx2T65jnhq90FECAbbfgavO xmoaVEHsSppJvPV2TjpmLmyQ= X-Envelope-To: linux-kernel@vger.kernel.org Received: by smtp.migadu.com with ESMTPS id 331d074107720a0c; Mon, 09 Nov 2026 02:58:16 +0000 X-Mizu-Trace-ID: 331d074107720a0c X-Migadu-Flow: FLOW_OUT From: Jiayuan Chen To: netdev@vger.kernel.org Cc: Jiayuan Chen , David Ahern , Ido Schimmel , "David S. Miller" , Eric Dumazet , Jakub Kicinski , Paolo Abeni , Simon Horman , Pablo Neira Ayuso , Florian Westphal , Phil Sutter , Nikolay Aleksandrov , Paul Moore , Matthieu Baerts , Mat Martineau , Geliang Tang , Julian Anastasov , Allison Henderson , Marcelo Ricardo Leitner , Xin Long , "D. Wythe" , Dust Li , Sidraya Jayagond , Mahanta Jambigi , Tony Lu , Wen Gu , linux-kernel@vger.kernel.org, netfilter-devel@vger.kernel.org, coreteam@netfilter.org, bridge@lists.linux.dev, linux-security-module@vger.kernel.org, mptcp@lists.linux.dev, lvs-devel@vger.kernel.org, linux-rdma@vger.kernel.org, rds-devel@oss.oracle.com, linux-sctp@vger.kernel.org, linux-s390@vger.kernel.org Subject: [PATCH net-next 07/14] mptcp: annotate data-races around pernet sysctls Date: Mon, 9 Nov 2026 10:52:06 +0800 Message-ID: <20261109025425.328445-8-jiayuan.chen@linux.dev> X-Mailer: git-send-email 2.43.0 In-Reply-To: <20261109025425.328445-1-jiayuan.chen@linux.dev> References: <20261109025425.328445-1-jiayuan.chen@linux.dev> X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Post: List-Help: List-Subscribe: List-Unsubscribe: List-Owner: Precedence: list MIME-Version: 1.0 Content-Transfer-Encoding: 8bit enabled, add_addr_timeout, checksum_enabled, allow_join_initial_addr_port, stale_loss_cnt, close_timeout, pm_type and syn_retrans_before_tcp_fallback are read by their ctrl.c helpers without any lock while the sysctl handlers update them with WRITE_ONCE(), and the path_manager handler stores pm_type with a plain write. Add READ_ONCE() to the readers and WRITE_ONCE() to that handler. KCSAN reports it when net.mptcp.enabled is changed while MPTCP sockets are being created: BUG: KCSAN: data-race in mptcp_is_enabled / proc_dou8vec_minmax write (marked) to 0xffff8d724248abc9 of 1 bytes by task 733 on cpu 3: proc_dou8vec_minmax+0x1ab/0x1f0 proc_sys_call_handler+0x282/0x3a0 proc_sys_write+0x13/0x20 ... read to 0xffff8d724248abc9 of 1 bytes by task 735 on cpu 1: mptcp_is_enabled+0x33/0x50 mptcp_init_sock+0x35/0x300 inet_create+0x4a6/0x8e0 ... value changed: 0x00 -> 0x01 Signed-off-by: Jiayuan Chen --- net/mptcp/ctrl.c | 18 +++++++++--------- 1 file changed, 9 insertions(+), 9 deletions(-) diff --git a/net/mptcp/ctrl.c b/net/mptcp/ctrl.c index 63c5747f0f63c..164f79b9deb0e 100644 --- a/net/mptcp/ctrl.c +++ b/net/mptcp/ctrl.c @@ -50,39 +50,39 @@ static struct mptcp_pernet *mptcp_get_pernet(const struct net *net) int mptcp_is_enabled(const struct net *net) { - return mptcp_get_pernet(net)->mptcp_enabled; + return READ_ONCE(mptcp_get_pernet(net)->mptcp_enabled); } unsigned int mptcp_get_add_addr_timeout(const struct net *net) { - return mptcp_get_pernet(net)->add_addr_timeout; + return READ_ONCE(mptcp_get_pernet(net)->add_addr_timeout); } int mptcp_is_checksum_enabled(const struct net *net) { - return mptcp_get_pernet(net)->checksum_enabled; + return READ_ONCE(mptcp_get_pernet(net)->checksum_enabled); } int mptcp_allow_join_id0(const struct net *net) { - return mptcp_get_pernet(net)->allow_join_initial_addr_port; + return READ_ONCE(mptcp_get_pernet(net)->allow_join_initial_addr_port); } unsigned int mptcp_stale_loss_cnt(const struct net *net) { - return mptcp_get_pernet(net)->stale_loss_cnt; + return READ_ONCE(mptcp_get_pernet(net)->stale_loss_cnt); } unsigned int mptcp_close_timeout(const struct sock *sk) { if (sock_flag(sk, SOCK_DEAD)) return TCP_TIMEWAIT_LEN; - return mptcp_get_pernet(sock_net(sk))->close_timeout; + return READ_ONCE(mptcp_get_pernet(sock_net(sk))->close_timeout); } int mptcp_get_pm_type(const struct net *net) { - return mptcp_get_pernet(net)->pm_type; + return READ_ONCE(mptcp_get_pernet(net)->pm_type); } const char *mptcp_get_path_manager(const struct net *net) @@ -230,7 +230,7 @@ static int proc_path_manager(const struct ctl_table *ctl, int write, pm_type = MPTCP_PM_TYPE_KERNEL; else if (strncmp(pm_name, "userspace", MPTCP_PM_NAME_MAX) == 0) pm_type = MPTCP_PM_TYPE_USERSPACE; - pernet->pm_type = pm_type; + WRITE_ONCE(pernet->pm_type, pm_type); } } @@ -551,7 +551,7 @@ void mptcp_active_detect_blackhole(struct sock *ssk, bool expired) net = sock_net(ssk); timeouts = inet_csk(ssk)->icsk_retransmits; - to_max = mptcp_get_pernet(net)->syn_retrans_before_tcp_fallback; + to_max = READ_ONCE(mptcp_get_pernet(net)->syn_retrans_before_tcp_fallback); if (timeouts == to_max || (timeouts < to_max && expired)) { subflow->mpc_drop = 1; -- 2.43.0