From nobody Mon Mar 2 08:30:01 2026 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 1418B303A35; Wed, 11 Feb 2026 19:07:00 +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=1770836820; cv=none; b=qokhCJoDE4TgwFT10/sZVbyl4/rkasuVj5AMIpDIhT4RmG16exSOtXAndgl6UJgCbfd/eHLrlUKqwVps0OpKs63FUq6niMWF9pUHM5UQ85xK4OfHdNsRggyqxNMnJUJXSsGd8qGWXk98pN7CGSAdHvOzUAgP5RMaTSQIQ6pvPMo= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1770836820; c=relaxed/simple; bh=rMABZ5ULTsN0/8tg3HM626ypUOFeIMxiTKhtnZu4SKc=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=fxwWvYm4cHZaPYuVPpj1lyc6DLVHctQ81P07crvO2PklvhAtDNWeiE4h8MrFbXWTz+NndVcvenOUuBUAU9+KmHn6DEu6jUqY2Qw3g3A8qBoJ+0+R0uZF578evA8CzZec+A7xJ51Rtylf1rBbps02FwRBbpNsLQAIdg60Zb/I0QY= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=TdmjTZNv; 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="TdmjTZNv" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 69FC0C19423; Wed, 11 Feb 2026 19:06:58 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1770836819; bh=rMABZ5ULTsN0/8tg3HM626ypUOFeIMxiTKhtnZu4SKc=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=TdmjTZNvzZ15iJ9pcgo7W1JzsO4Xi8iyVSe0VFVQBUGJLOOLv+01Zv+wyjpl+p006 vPZImeO7gYAIs1BbYTP0j1t4LYtcsa0ew8ZfJQ64KFTj9vOnTfe4FSTSDrcUpEQO5C OM6NMHWjSX6Bw1eMdItL/EhimX3dgZUiZzKXOMgczmMN/XMRDvcah2rox9FyO0sA1n GrpDIrj3ohwPMITz6MEr/Koe7ls+noNFpvD2XBdqA2jIklEY7/8HSo2VEJuf4Z7RfU uXwjC7JgryQJB9ZOBZSTbErO7GG546QFj/zsSk08RVJuUyuSccXG7Ir9KSBL4/4nU0 E0NthlffJB4Jw== From: "Matthieu Baerts (NGI0)" To: mptcp@lists.linux.dev, stable@vger.kernel.org, gregkh@linuxfoundation.org Cc: Paolo Abeni , sashal@kernel.org, "Matthieu Baerts (NGI0)" Subject: [PATCH 6.1.y 3/6] mptcp: ensure context reset on disconnect() Date: Wed, 11 Feb 2026 20:06:21 +0100 Message-ID: <20260211190617.77192-11-matttbe@kernel.org> X-Mailer: git-send-email 2.51.0 In-Reply-To: <20260211190617.77192-8-matttbe@kernel.org> References: <20260211190617.77192-8-matttbe@kernel.org> Precedence: bulk X-Mailing-List: mptcp@lists.linux.dev List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 X-Developer-Signature: v=1; a=openpgp-sha256; l=5474; i=matttbe@kernel.org; h=from:subject; bh=w+gVDIMZ7MyhCPB9jDcoWtrmZeRTY8/GXkykQ/ll+k8=; b=owGbwMvMwCVWo/Th0Gd3rumMp9WSGDJ7LusZ+7yU+/+55MaiN14N5w6Vn81j2tWcPHuaXNWG7 GeWSma8HaUsDGJcDLJiiizSbZH5M59X8ZZ4+VnAzGFlAhnCwMUpABO5Ls3IsG3FF1slpWn/Qntb phrnLz14TYLpYXip99F9533/PTZ/ksTI0H3bXyln8tQ7yjuOxEmd3Or8NqPP6oXl2d1CIUIaN1+ fYwQA X-Developer-Key: i=matttbe@kernel.org; a=openpgp; fpr=E8CB85F76877057A6E27F77AF6B7824F4269A073 Content-Transfer-Encoding: quoted-printable Content-Type: text/plain; charset="utf-8" From: Paolo Abeni commit 86730ac255b0497a272704de9a1df559f5d6602e upstream. 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) Link: https://patch.msgid.link/20251212-net-mptcp-subflow_data_ready-warn-v= 1-2-d1f9fd1c36c8@kernel.org Signed-off-by: Paolo Abeni [ Conflicts in protocol.[ch] because the context has changed. ] Signed-off-by: Matthieu Baerts (NGI0) --- net/mptcp/protocol.c | 9 ++++++--- net/mptcp/protocol.h | 3 ++- 2 files changed, 8 insertions(+), 4 deletions(-) diff --git a/net/mptcp/protocol.c b/net/mptcp/protocol.c index ad0bfdd308be..5274b19a5dbd 100644 --- a/net/mptcp/protocol.c +++ b/net/mptcp/protocol.c @@ -2456,10 +2456,10 @@ 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 */ @@ -2511,7 +2511,7 @@ 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); if (msk->subflow && ssk =3D=3D msk->subflow->sk) msk->subflow->state =3D SS_UNCONNECTED; release_sock(ssk); @@ -2802,6 +2802,8 @@ static void mptcp_do_fastclose(struct sock *sk) struct mptcp_subflow_context *subflow, *tmp; struct mptcp_sock *msk =3D mptcp_sk(sk); =20 + msk->fastclosing =3D 1; + /* Explicitly send the fastclose reset as need */ if (__mptcp_check_fallback(msk)) return; @@ -3290,6 +3292,7 @@ static int mptcp_disconnect(struct sock *sk, int flag= s) WRITE_ONCE(msk->csum_enabled, mptcp_is_checksum_enabled(sock_net(sk))); mptcp_pm_data_reset(msk); mptcp_ca_reset(sk); + msk->fastclosing =3D 0; =20 WRITE_ONCE(sk->sk_shutdown, 0); sk_error_report(sk); diff --git a/net/mptcp/protocol.h b/net/mptcp/protocol.h index 6575712c789e..dd5070d57d74 100644 --- a/net/mptcp/protocol.h +++ b/net/mptcp/protocol.h @@ -289,7 +289,8 @@ struct mptcp_sock { nodelay:1, fastopening:1, in_accept_queue:1, - free_first:1; + free_first:1, + fastclosing:1; int keepalive_cnt; int keepalive_idle; int keepalive_intvl; --=20 2.51.0