From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-alma10-1.taild15c8.ts.net [100.103.45.18]) (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 513553B388B for ; Sat, 30 May 2026 14:17:34 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=100.103.45.18 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1780150655; cv=none; b=V9LKxCPtgSkYjtP0nV2uDw0DLXy6C28OVcdfd/JvIRTMVICIJ8NSgWBBlNEXhlpE7IUOgGwdtxLzGYgJTkWvfhFO/ES2KSOZEZvE2u5KBNMQjIfFjBt/KxckuO1Nw04KLvMTEjFqRARL2mPuhkb5Yd4O4hywyvad7OZdEvZHmO4= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1780150655; c=relaxed/simple; bh=wmxxM8y3NB/J7C2uAPCjn3R/mwmgxtbfjJnk/x5/9b8=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=jCLBHTJU4PwICafrviMwzY9buYQXAt/D5lQwEgrveraf4gL+vagFsajl6QIfGc8mnt2EFlx6TEL5oKwTS3lCv5ORtjB/mIrt3mRNIvb6kzf5DD+IBo75lnpKPXUbxTHERm4NbDJZeAkkejqy827eYBWOLD7Ky4kgKx7NjWfhb3U= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=dGimDOwO; arc=none smtp.client-ip=100.103.45.18 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="dGimDOwO" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 5A3B01F0089A; Sat, 30 May 2026 14:17:33 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel.org; s=k20260515; t=1780150654; bh=Dp+ce52Gw4GbogvXO3ZgzZi3+ozZoYKk8hwH9MQR4tA=; h=From:To:Cc:Subject:Date:In-Reply-To:References; b=dGimDOwOuLTGHLy0xdMH0UIPohfGlqXV7ZDRgon/zVLJKf8FpfoygFiIId5cF0cY6 YE6r+qmzVWpzHhWdXYQoMY4/ZPzR3QP5tRqXg7NJMC+bayceImP9EZJoW9zL/QEePD ITcDrVYshj0KR1N9F3+eayXUdUCqgF/TrpkAZonkX496s/+EJxENRZTxHBidDubcjU ehaErQsnKR/dcdk8ib+5c3zzONsG3QIKcBI1ykVjWv/3RQ1winr2lE0Mho5UivHzvg TIDe/b4NeqvUJyb669vakLNGe4JJDCXQAsJ0KxVQ8vJtu7TwtYPccObjK0mQhpLjj/ YudO1Uq6e0Atg== From: Sasha Levin To: stable@vger.kernel.org Cc: Paolo Abeni , Geliang Tang , Mat Martineau , "Matthieu Baerts (NGI0)" , Jakub Kicinski , Sasha Levin Subject: [PATCH 6.6.y 2/3] mptcp: cleanup fallback dummy mapping generation Date: Sat, 30 May 2026 10:17:27 -0400 Message-ID: <20260530141728.2398427-2-sashal@kernel.org> X-Mailer: git-send-email 2.53.0 In-Reply-To: <20260530141728.2398427-1-sashal@kernel.org> References: <2026052851-deskbound-cardigan-c96b@gregkh> <20260530141728.2398427-1-sashal@kernel.org> 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 2834f8edd74d5dda368087a654c0e52b141e9893 ] MPTCP currently access ack_seq outside the msk socket log scope to generate the dummy mapping for fallback socket. Soon we are going to introduce backlog usage and even for fallback socket the ack_seq value will be significantly off outside of the msk socket lock scope. Avoid relying on ack_seq for dummy mapping generation, using instead the subflow sequence number. Note that in case of disconnect() and (re)connect() we must ensure that any previous state is re-set. Signed-off-by: Paolo Abeni Reviewed-by: Geliang Tang Tested-by: Geliang Tang Reviewed-by: Mat Martineau Signed-off-by: Matthieu Baerts (NGI0) Link: https://patch.msgid.link/20251121-net-next-mptcp-memcg-backlog-imp-v1-6-1f34b6c1e0b1@kernel.org Signed-off-by: Jakub Kicinski Stable-dep-of: 0981f90e1a05 ("mptcp: reset rcv wnd on disconnect") Signed-off-by: Sasha Levin --- net/mptcp/protocol.c | 3 +++ net/mptcp/subflow.c | 8 +++++++- 2 files changed, 10 insertions(+), 1 deletion(-) diff --git a/net/mptcp/protocol.c b/net/mptcp/protocol.c index aed6c04c7de67..abb9a9764b61a 100644 --- a/net/mptcp/protocol.c +++ b/net/mptcp/protocol.c @@ -3327,6 +3327,9 @@ static int mptcp_disconnect(struct sock *sk, int flags) msk->rcvspace_init = 0; msk->fastclosing = 0; + /* for fallback's sake */ + WRITE_ONCE(msk->ack_seq, 0); + WRITE_ONCE(sk->sk_shutdown, 0); sk_error_report(sk); return 0; diff --git a/net/mptcp/subflow.c b/net/mptcp/subflow.c index b8a8718573e62..d3b5c2d48b530 100644 --- a/net/mptcp/subflow.c +++ b/net/mptcp/subflow.c @@ -471,6 +471,9 @@ static void subflow_set_remote_key(struct mptcp_sock *msk, mptcp_crypto_key_sha(subflow->remote_key, NULL, &subflow->iasn); subflow->iasn++; + /* for fallback's sake */ + subflow->map_seq = subflow->iasn; + WRITE_ONCE(msk->remote_key, subflow->remote_key); WRITE_ONCE(msk->ack_seq, subflow->iasn); WRITE_ONCE(msk->can_ack, true); @@ -1382,9 +1385,12 @@ static bool subflow_check_data_avail(struct sock *ssk) skb = skb_peek(&ssk->sk_receive_queue); subflow->map_valid = 1; - subflow->map_seq = READ_ONCE(msk->ack_seq); subflow->map_data_len = skb->len; subflow->map_subflow_seq = tcp_sk(ssk)->copied_seq - subflow->ssn_offset; + subflow->map_seq = __mptcp_expand_seq(subflow->map_seq, + subflow->iasn + + TCP_SKB_CB(skb)->seq - + subflow->ssn_offset - 1); WRITE_ONCE(subflow->data_avail, true); return true; } -- 2.53.0