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 E5A8536B071; Sun, 7 Jun 2026 10:59:58 +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=1780830008; cv=none; b=DAUexjue884ZXEw4w6tuBkB1BoO6SaWh0RFjX7hDq3EhJ+eX0q/7W5FQCxnbWjdvy0Nek/2qPyO4tpNDr+mG/83PxHrXm9GIpUonKQFxJZFL8x+85ZuKYAUpuXNFLlMCDcCJR+9uQlWkEn2wbuOnUXUHRltOM2uMkPftJsDREkw= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1780830008; c=relaxed/simple; bh=bzjk62nZP5G1Yk90SUXwpq8Kfb6cZ0GjN+0MhctbR+0=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=b5rMV9h4viGZqO5fFO3FLkVB5tKDRVRGZwP15rjc51tU8SbVm5aPn/KDBMHC6ilfGEWRWnTDfeh1oEDkDLv9y7AvgHrxIfRlb6ZzxVccuF2F17BIuMkP4ISv3QTLArteIXYPuBdysNNISj045YpAi77jWuY+3s3wu//VLjQZu+s= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b=mcrBH81V; arc=none smtp.client-ip=100.103.45.18 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b="mcrBH81V" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 8B3BE1F00893; Sun, 7 Jun 2026 10:59:57 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linuxfoundation.org; s=korg; t=1780829998; bh=ZZStdIpdmWC0pThnYKtyzFtEasdh5VDwYe5L5HWTA2k=; h=From:To:Cc:Subject:Date:In-Reply-To:References; b=mcrBH81V3pCbvv84aWKis47dkq+soEf1gMt1VzhDSABbpfeqRwsRcUGJpHfseGDGa 7UrVJR322LJkK3Vt2CtgWdBDQR1HY4VbVgYmeStDakNR3ww6jM5uZ4vOIsBumznLVx 9eq+GIuGn2Sk2VIrb88WERT81WwYj7mJwTQuXafQ= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, Paolo Abeni , Geliang Tang , Mat Martineau , "Matthieu Baerts (NGI0)" , Jakub Kicinski , Sasha Levin Subject: [PATCH 6.18 298/315] mptcp: cleanup fallback dummy mapping generation Date: Sun, 7 Jun 2026 12:01:25 +0200 Message-ID: <20260607095738.541844462@linuxfoundation.org> X-Mailer: git-send-email 2.54.0 In-Reply-To: <20260607095727.528828913@linuxfoundation.org> References: <20260607095727.528828913@linuxfoundation.org> User-Agent: quilt/0.69 X-stable: review X-Patchwork-Hint: ignore Precedence: bulk X-Mailing-List: patches@lists.linux.dev List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit 6.18-stable review patch. If anyone has any objections, please let me know. ------------------ 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 Signed-off-by: Greg Kroah-Hartman --- net/mptcp/protocol.c | 3 +++ net/mptcp/subflow.c | 8 +++++++- 2 files changed, 10 insertions(+), 1 deletion(-) --- a/net/mptcp/protocol.c +++ b/net/mptcp/protocol.c @@ -3333,6 +3333,9 @@ static int mptcp_disconnect(struct sock 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; --- a/net/mptcp/subflow.c +++ b/net/mptcp/subflow.c @@ -491,6 +491,9 @@ static void subflow_set_remote_key(struc 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); @@ -1435,9 +1438,12 @@ reset: 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; }