From nobody Sun Dec 14 12:14:19 2025 Received: from us-smtp-delivery-124.mimecast.com (us-smtp-delivery-124.mimecast.com [170.10.129.124]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id E9D0131DD86 for ; Fri, 5 Dec 2025 09:59:25 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=170.10.129.124 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1764928774; cv=none; b=KNjVKbqyODFtJ4Y7H5c7JxPxJcFVQO2OVMxSi6o++ic6oGDjoSrfWnJCNCrMIK1NuwWvg115mYqe6VlPva6IgiFMImhvo2ImaPqWqATzhWb5Y5zLF161yGc6QmbwKMHjyfPMB6f4OJ0PY5bsZH1LA8fX3iTWdk1aF3YHk9oG/YY= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1764928774; c=relaxed/simple; bh=crXI+tQ2RkoDjptHGVO9YQSgQSndTYHU75i1FvWRjX8=; h=From:To:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version:content-type; b=rlmc5bW6+hD7VPmvWMX3dkFhQVyH0n5UjOho+hegWKDkL57XqmIHth8QDjLzeE2ROpr4NF+5Ylxu4EZFhu4gO7SIvSSI5m2G6QPGAOYG5t4sVcrhqmtX5gA/1HPlWIt6Mv0RJiSfG/fatBvE2NWp28xpMxe6gv8E5WGpIDmNuR8= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dmarc=pass (p=quarantine dis=none) header.from=redhat.com; spf=pass smtp.mailfrom=redhat.com; dkim=pass (1024-bit key) header.d=redhat.com header.i=@redhat.com header.b=ejdy7boe; arc=none smtp.client-ip=170.10.129.124 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=quarantine dis=none) header.from=redhat.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=redhat.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=redhat.com header.i=@redhat.com header.b="ejdy7boe" DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1764928760; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:mime-version:mime-version:content-type:content-type: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=7hQKXkpLtHJKGW8r0u5Jmzd7mS+sAu7yJDxxTPMGyjA=; b=ejdy7boecRwTkRxWF3P3arIg/wq/u+8BwCMzJPihY8H6ge6HhhOQ/5uJTt+6+5QOdOcRAz txP83eRsV7S0WIMFsqwdzKb+Mx8Eqz/lFXCJK9Ya0s5TMw6KS5Oz86RlFi6AEC++p5K2lp akiiOKBZxAXyRVuQR1/vu9eqEjFcXog= Received: from mx-prod-mc-05.mail-002.prod.us-west-2.aws.redhat.com (ec2-54-186-198-63.us-west-2.compute.amazonaws.com [54.186.198.63]) by relay.mimecast.com with ESMTP with STARTTLS (version=TLSv1.3, cipher=TLS_AES_256_GCM_SHA384) id us-mta-687-WwNEC5-bPNWDMD-nqSRMxw-1; Fri, 05 Dec 2025 04:59:19 -0500 X-MC-Unique: WwNEC5-bPNWDMD-nqSRMxw-1 X-Mimecast-MFC-AGG-ID: WwNEC5-bPNWDMD-nqSRMxw_1764928758 Received: from mx-prod-int-01.mail-002.prod.us-west-2.aws.redhat.com (mx-prod-int-01.mail-002.prod.us-west-2.aws.redhat.com [10.30.177.4]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature RSA-PSS (2048 bits) server-digest SHA256) (No client certificate requested) by mx-prod-mc-05.mail-002.prod.us-west-2.aws.redhat.com (Postfix) with ESMTPS id 8A567195608F for ; Fri, 5 Dec 2025 09:59:18 +0000 (UTC) Received: from gerbillo.redhat.com (unknown [10.45.224.159]) by mx-prod-int-01.mail-002.prod.us-west-2.aws.redhat.com (Postfix) with ESMTP id AAFF63011A84 for ; Fri, 5 Dec 2025 09:59:17 +0000 (UTC) From: Paolo Abeni To: mptcp@lists.linux.dev Subject: [PATCH mptcp-net v3 2/2] mptcp: ensure context reset on disconnect() Date: Fri, 5 Dec 2025 10:58:43 +0100 Message-ID: <84e58b8d3665b7d363807fd53369ae0dfde0ad12.1764928598.git.pabeni@redhat.com> In-Reply-To: References: Precedence: bulk X-Mailing-List: mptcp@lists.linux.dev List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 X-Scanned-By: MIMEDefang 3.4.1 on 10.30.177.4 X-Mimecast-Spam-Score: 0 X-Mimecast-MFC-PROC-ID: lN1LU2TYpRdC_Ccw0ZC-LzgZIPrqHN5Cwx_gWAKUpVM_1764928758 X-Mimecast-Originator: redhat.com Content-Transfer-Encoding: quoted-printable Content-Type: text/plain; charset="utf-8"; x-default="true" After the blamed commit below, if the MPC subflow is already in TCP_CLOSE status or has fallback to TCP at mptcp_disconnect() time, mptcp_do_fastclose() skips setting the `send_fastclose flag` and the later __mptcp_close_ssk() does not reset anymore the related subflow context. Any later connection will be created with both the `request_mptcp` flag and the msk-level fallback status off (it is unconditionally cleared at MPTCP disconnect time), leading to a warning in subflow_data_ready(): WARNING: CPU: 26 PID: 8996 at net/mptcp/subflow.c:1519 subflow_data_ready = (net/mptcp/subflow.c:1519 (discriminator 13)) Modules linked in: CPU: 26 UID: 0 PID: 8996 Comm: syz.22.39 Not tainted 6.18.0-rc7-05427-g11f= c074f6c36 #1 PREEMPT(voluntary) Hardware name: Bochs Bochs, BIOS Bochs 01/01/2011 RIP: 0010:subflow_data_ready (net/mptcp/subflow.c:1519 (discriminator 13)) Code: 90 0f 0b 90 90 e9 04 fe ff ff e8 b7 1e f5 fe 89 ee bf 07 00 00 00 e8= db 19 f5 fe 83 fd 07 0f 84 35 ff ff ff e8 9d 1e f5 fe 90 <0f> 0b 90 e9 27 = ff ff ff e8 8f 1e f5 fe 4c 89 e7 48 89 de e8 14 09 RSP: 0018:ffffc9002646fb30 EFLAGS: 00010293 RAX: 0000000000000000 RBX: ffff88813b218000 RCX: ffffffff825c8435 RDX: ffff8881300b3580 RSI: ffffffff825c8443 RDI: 0000000000000005 RBP: 000000000000000b R08: ffffffff825c8435 R09: 000000000000000b R10: 0000000000000005 R11: 0000000000000007 R12: ffff888131ac0000 R13: 0000000000000000 R14: 0000000000000000 R15: 0000000000000000 FS: 00007f88330af6c0(0000) GS:ffff888a93dd2000(0000) knlGS:00000000000000= 00 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007f88330aefe8 CR3: 000000010ff59000 CR4: 0000000000350ef0 Call Trace: tcp_data_ready (net/ipv4/tcp_input.c:5356) tcp_data_queue (net/ipv4/tcp_input.c:5445) tcp_rcv_state_process (net/ipv4/tcp_input.c:7165) tcp_v4_do_rcv (net/ipv4/tcp_ipv4.c:1955) __release_sock (include/net/sock.h:1158 (discriminator 6) net/core/sock.c= :3180 (discriminator 6)) release_sock (net/core/sock.c:3737) mptcp_sendmsg (net/mptcp/protocol.c:1763 net/mptcp/protocol.c:1857) inet_sendmsg (net/ipv4/af_inet.c:853 (discriminator 7)) __sys_sendto (net/socket.c:727 (discriminator 15) net/socket.c:742 (discr= iminator 15) net/socket.c:2244 (discriminator 15)) __x64_sys_sendto (net/socket.c:2247) do_syscall_64 (arch/x86/entry/syscall_64.c:63 (discriminator 1) arch/x86/= entry/syscall_64.c:94 (discriminator 1)) entry_SYSCALL_64_after_hwframe (arch/x86/entry/entry_64.S:130) RIP: 0033:0x7f883326702d Address the issue setting an explicit `fastclosing` flag at fastclose time, and checking such flag subflows after mptcp_do_fastclose(). Fixes: ae155060247b ("mptcp: fix duplicate reset on fastclose") Signed-off-by: Paolo Abeni --- net/mptcp/protocol.c | 8 +++++--- net/mptcp/protocol.h | 3 ++- 2 files changed, 7 insertions(+), 4 deletions(-) diff --git a/net/mptcp/protocol.c b/net/mptcp/protocol.c index e484c6391b48..6c02835b6d60 100644 --- a/net/mptcp/protocol.c +++ b/net/mptcp/protocol.c @@ -2467,10 +2467,10 @@ bool __mptcp_retransmit_pending_data(struct sock *s= k) */ static void __mptcp_subflow_disconnect(struct sock *ssk, struct mptcp_subflow_context *subflow, - unsigned int flags) + bool fastclosing) { if (((1 << ssk->sk_state) & (TCPF_CLOSE | TCPF_LISTEN)) || - subflow->send_fastclose) { + fastclosing) { /* The MPTCP code never wait on the subflow sockets, TCP-level * disconnect should never fail */ @@ -2538,7 +2538,7 @@ static void __mptcp_close_ssk(struct sock *sk, struct= sock *ssk, =20 need_push =3D (flags & MPTCP_CF_PUSH) && __mptcp_retransmit_pending_data(= sk); if (!dispose_it) { - __mptcp_subflow_disconnect(ssk, subflow, flags); + __mptcp_subflow_disconnect(ssk, subflow, msk->fastclosing); release_sock(ssk); =20 goto out; @@ -2881,6 +2881,7 @@ static void mptcp_do_fastclose(struct sock *sk) =20 mptcp_set_state(sk, TCP_CLOSE); mptcp_backlog_purge(sk); + msk->fastclosing =3D 1; =20 /* Explicitly send the fastclose reset as need */ if (__mptcp_check_fallback(msk)) @@ -3415,6 +3416,7 @@ static int mptcp_disconnect(struct sock *sk, int flag= s) msk->bytes_sent =3D 0; msk->bytes_retrans =3D 0; msk->rcvspace_init =3D 0; + msk->fastclosing =3D 0; =20 /* for fallback's sake */ WRITE_ONCE(msk->ack_seq, 0); diff --git a/net/mptcp/protocol.h b/net/mptcp/protocol.h index 41d80df1ba3e..d0b3834e98b8 100644 --- a/net/mptcp/protocol.h +++ b/net/mptcp/protocol.h @@ -321,7 +321,8 @@ struct mptcp_sock { fastopening:1, in_accept_queue:1, free_first:1, - rcvspace_init:1; + rcvspace_init:1, + fastclosing:1; u32 notsent_lowat; int keepalive_cnt; int keepalive_idle; --=20 2.52.0