From mboxrd@z Thu Jan 1 00:00:00 1970 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 B0FFE2EB5B8 for ; Tue, 6 Jan 2026 23:07:54 +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=1767740874; cv=none; b=s3FMLDSidnWHCz2BWtaQ0VFNUAvCCp4NMcQDkut40DQ8bPlw33+RxYVJfYcgfo5klUGwl4crfimDN/BKaezR7i22b2SZo/HmVZJgEMp9vEGaFrW8T34qgo5P7+I3pmVEZCZ82CWagWJMjRcX7uT04L973z/DC1iBFSTgQb9+IWU= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1767740874; c=relaxed/simple; bh=X6ROx7DZgQ3EirxbdHfO3RZvzn1Ve7AqdH2c6cYquXA=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=FcF1qYtlQ0H0YjZ/ye6zgkNydT/12cmaY1NaJ0f2BNEstl7f3sCEw1pBGQCpk7r1MvQmVrO3UXdQVGJvWgBEFT7X/lIYgl6PlNKllGX0WZeBvKzXc5Lico3RvMWEgJ3+o8vo9CqGWQMhnuUnVBucSdaEkTYJFbaVfGfDsY1K/z0= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=BzBBt49O; 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="BzBBt49O" Received: by smtp.kernel.org (Postfix) with ESMTPSA id C7802C19421; Tue, 6 Jan 2026 23:07:53 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1767740874; bh=X6ROx7DZgQ3EirxbdHfO3RZvzn1Ve7AqdH2c6cYquXA=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=BzBBt49OMWzHOPU2q1ZcJWx4rMR0vMm5OWx/97xJp3A4txGO5jBxy8HC9oc4Hxcvk hI/IxKGEU7WBp/nuA1Zucq/94M4GehMe3eSVKaJoY1szbbSP/19EIsU95Eyy2MWPiZ ffQ9js49ZwKqszuSUguoglh5ZR6e2DjGmJXDHWyCuoVAkmlDUmbjRYw1ybclAgQ/AM iitminNwmhuRKGYyAbUEL+796p0ZvZG2eh9srM8wCA/cD3QWuQtZab9gcJevH43lRP wIg5BN3sJ4Vq6S2q1dyfb+uLaKt6dQJ4ffv2Bak6ojNzNsLUu8CxRg27E5rkCzkQv5 A3xvuVK+ewk0A== From: Sasha Levin To: stable@vger.kernel.org Cc: Paolo Abeni , "Matthieu Baerts (NGI0)" , Sasha Levin Subject: [PATCH 6.12.y] mptcp: ensure context reset on disconnect() Date: Tue, 6 Jan 2026 18:07:52 -0500 Message-ID: <20260106230752.3447994-1-sashal@kernel.org> X-Mailer: git-send-email 2.51.0 In-Reply-To: <2026010549-throwaway-structure-a291@gregkh> References: <2026010549-throwaway-structure-a291@gregkh> Precedence: bulk X-Mailing-List: stable@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit From: Paolo Abeni [ Upstream commit 86730ac255b0497a272704de9a1df559f5d6602e ] 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-g11fc074f6c36 #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:0000000000000000 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 (discriminator 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-v1-2-d1f9fd1c36c8@kernel.org Signed-off-by: Paolo Abeni [ Adjust context ] Signed-off-by: Sasha Levin --- 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 ed29132fd48e..37b50c6edf3b 100644 --- a/net/mptcp/protocol.c +++ b/net/mptcp/protocol.c @@ -2475,10 +2475,10 @@ bool __mptcp_retransmit_pending_data(struct sock *sk) */ 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 */ @@ -2530,7 +2530,7 @@ static void __mptcp_close_ssk(struct sock *sk, struct sock *ssk, need_push = (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); goto out; @@ -2839,6 +2839,7 @@ static void mptcp_do_fastclose(struct sock *sk) struct mptcp_sock *msk = mptcp_sk(sk); mptcp_set_state(sk, TCP_CLOSE); + msk->fastclosing = 1; /* Explicitly send the fastclose reset as need */ if (__mptcp_check_fallback(msk)) @@ -3356,6 +3357,7 @@ static int mptcp_disconnect(struct sock *sk, int flags) msk->bytes_sent = 0; msk->bytes_retrans = 0; msk->rcvspace_init = 0; + msk->fastclosing = 0; WRITE_ONCE(sk->sk_shutdown, 0); sk_error_report(sk); diff --git a/net/mptcp/protocol.h b/net/mptcp/protocol.h index 73b842350677..c1c1bc19d61b 100644 --- a/net/mptcp/protocol.h +++ b/net/mptcp/protocol.h @@ -316,7 +316,8 @@ 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; -- 2.51.0