From nobody Sun Dec 14 11:53:48 2025 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (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 ED1082DEA7E; Fri, 12 Dec 2025 12:54:28 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1765544069; cv=none; b=UUuME8R+yYfdT6vJnU6BayB7to8LRP2wAVN2XaqUoAwzRrpNH82nVBr0ONUqh0PESN/YKfr6Nnb8aeiq3oufRLbzmRnMzb9HltOStKG4Ysr/5GrgfwGskXJ5biEJvrrivpCuCBi9SmUwdmgL5rAGFYPIMSEk889Am6CFHCcqe5E= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1765544069; c=relaxed/simple; bh=24z9XLTQ22YXFg4v3bCg/BynCPNKmWNPZjCJU+rlM0o=; h=From:Date:Subject:MIME-Version:Content-Type:Message-Id:References: In-Reply-To:To:Cc; b=WHK02PgySZNxs1FUXGyZGU7K906qzvHwrJgzciJUghjYlMhq1JwsmSV1+CRwiTnH2DwNHUswC8tST/wzkLloaBLzUAcUCVaqbUfSCMap0Kw29LWboqdrJSzqskZQOZlpMSZwItUS3EjiEj66+foi+bk1xEMN2enr+jRyE/usWnU= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=K3egwK5x; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="K3egwK5x" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 57485C4CEF1; Fri, 12 Dec 2025 12:54:26 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1765544068; bh=24z9XLTQ22YXFg4v3bCg/BynCPNKmWNPZjCJU+rlM0o=; h=From:Date:Subject:References:In-Reply-To:To:Cc:From; b=K3egwK5xvEjhs4PjDFJyaC0pqfj7z/54S9QP8paRwTCsZ+L4oSy/I9Xbrc+jg38LT bUwNV4ky2foK7hAW7bO2LfbE3UzZhVcv9CHno1njbvboq1qOaUWxkS6RB0TM89xQT/ +2ZUEZBKG5/16QZ/GUJJjTu6JVnecCzmD1LOA7/VYn5ZKWz2KZ9cIZxe9MJZ6gqwms rybOQHwCY0v9SyRuWprQPfP3lZffP+3x881FDj9PfEzcF8GVuDDeN4ExCTHDb3Am74 BQqQ2imqbviuge12EAmWA9bv6qsNdWm1lnxhCZBeN+u4bYiJOP2VZ2sBT5BiQmh5p2 aJ79wrU22VOdg== From: "Matthieu Baerts (NGI0)" Date: Fri, 12 Dec 2025 13:54:04 +0100 Subject: [PATCH net 2/2] mptcp: ensure context reset on disconnect() Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: quoted-printable Message-Id: <20251212-net-mptcp-subflow_data_ready-warn-v1-2-d1f9fd1c36c8@kernel.org> References: <20251212-net-mptcp-subflow_data_ready-warn-v1-0-d1f9fd1c36c8@kernel.org> In-Reply-To: <20251212-net-mptcp-subflow_data_ready-warn-v1-0-d1f9fd1c36c8@kernel.org> To: Mat Martineau , Geliang Tang , "David S. Miller" , Eric Dumazet , Jakub Kicinski , Paolo Abeni , Simon Horman , Kuniyuki Iwashima , Dmytro Shytyi Cc: Evan Li , kitta , netdev@vger.kernel.org, mptcp@lists.linux.dev, linux-kernel@vger.kernel.org, "Matthieu Baerts (NGI0)" , stable@vger.kernel.org X-Mailer: b4 0.14.3 X-Developer-Signature: v=1; a=openpgp-sha256; l=4983; i=matttbe@kernel.org; h=from:subject:message-id; bh=ii0pIAmHV5NlbAXWXwn5SjI5o4z+0k4kET2gfhSGy7M=; b=owGbwMvMwCVWo/Th0Gd3rumMp9WSGDJtBKoFfltuEgsRttX/Pc/r1I9p8h2rrdlTmyd+3DBDI aa8IKu/o5SFQYyLQVZMkUW6LTJ/5vMq3hIvPwuYOaxMIEMYuDgFYCI5jYwMv91nz2JZxJ7DGnH5 o3rVxqV9E34vuX7i5owfn1afFjmScZGRYcG3x0fuR4jOqdF48csvw+hxzqQ7dZ3K+ycU+D29tMn cnR0A X-Developer-Key: i=matttbe@kernel.org; a=openpgp; fpr=E8CB85F76877057A6E27F77AF6B7824F4269A073 From: Paolo Abeni 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-g11= fc074f6c36 #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 e= 8 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:0000000000000= 000 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 (disc= riminator 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 after mptcp_do_fastclose(). Fixes: ae155060247b ("mptcp: fix duplicate reset on fastclose") Cc: stable@vger.kernel.org Signed-off-by: Paolo Abeni Reviewed-by: Matthieu Baerts (NGI0) Signed-off-by: Matthieu Baerts (NGI0) --- 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 9b1fafd87cb9..f505b780f713 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; @@ -2884,6 +2884,7 @@ 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)) @@ -3418,6 +3419,7 @@ 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 bed0c9aa28b6..66e973500791 100644 --- a/net/mptcp/protocol.h +++ b/net/mptcp/protocol.h @@ -320,7 +320,8 @@ 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 2.51.0