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 B96CA45BD71; Tue, 16 Jun 2026 16:01:58 +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=1781625719; cv=none; b=aer8VUf3eLEu2RvFjgskZk5PysmTJbWHv6GJLEc4Sd0FKEvSIPBhFi+OCFMMsS0T/PzC9ril5a86Da3HTLqyyDwIcraF+daKOklhLQrZ75CXXY7rjLX4IihO9hIoU5H5buB2vi9XXXz0YvZZBaNKT7JAOHMlLe1A7Kg5PbsV54Q= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1781625719; c=relaxed/simple; bh=WuroVrQ2CgqyztHBQGDzSXsxRK8McD/e/eirXkxCbWM=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=TAzceL/ozftYpcfQVD3cng/h2Q02Uqdji+feeS5ujchDluB+xrBs1WUHRpb0kF9+P6pgww47NWKXcPhW0zV9aobO1hjaVR+EjcltBDaOB5NpmdtP8qGStHJjHfOhbUFM5c1fgoFIZ19zQWrXf4/6yWU0cdPLMWZGvw4kt6XySbw= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b=jFPrUhiM; 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="jFPrUhiM" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 4EC451F000E9; Tue, 16 Jun 2026 16:01:57 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linuxfoundation.org; s=korg; t=1781625718; bh=uKLpg1nrdt6VIxeWRb8EgjNmGdsCCZMA/TLJYgnGkzw=; h=From:To:Cc:Subject:Date:In-Reply-To:References; b=jFPrUhiMkxCyuFZluX75BfRWLP8kIVd9FNJhdMuAZBEe5RyRUm2pshv6zlBOMAqrJ mPRbmYm0gRqPUnedtVEHYjJ7UzEXibsWzE56wgzF1UvEy4tSiHbRFI3GmJb1pzr6sE N73WyJr4p4PYn3pHdr7td5vw2QK5bZ/p2LHvNtpk= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, Paolo Abeni , "Matthieu Baerts (NGI0)" , Jakub Kicinski Subject: [PATCH 6.18 195/325] mptcp: fix retransmission loop when csum is enabled Date: Tue, 16 Jun 2026 20:29:51 +0530 Message-ID: <20260616145107.676629069@linuxfoundation.org> X-Mailer: git-send-email 2.54.0 In-Reply-To: <20260616145057.827196531@linuxfoundation.org> References: <20260616145057.827196531@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 commit d1918b36edcaed0ec4ef6888b2358c6b1ddcff47 upstream. Sashiko noted that retransmission with csum enabled can actually transmit new data, but currently the relevant code does not update accordingly snd_nxt. The may cause incoming ack drop and an endless retransmission loop. Address the issue incrementing snd_nxt as needed. Fixes: 4e14867d5e91 ("mptcp: tune re-injections for csum enabled mode") 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/20260602-net-mptcp-misc-fixes-7-1-rc7-v2-2-856831229976@kernel.org Signed-off-by: Jakub Kicinski Signed-off-by: Greg Kroah-Hartman --- net/mptcp/protocol.c | 4 ++++ 1 file changed, 4 insertions(+) --- a/net/mptcp/protocol.c +++ b/net/mptcp/protocol.c @@ -2759,6 +2759,10 @@ static void __mptcp_retrans(struct sock msk->bytes_retrans += len; dfrag->already_sent = max(dfrag->already_sent, len); + /* With csum enabled retransmission can send new data. */ + if (after64(dfrag->already_sent + dfrag->data_seq, msk->snd_nxt)) + WRITE_ONCE(msk->snd_nxt, dfrag->already_sent + dfrag->data_seq); + reset_timer: mptcp_check_and_set_pending(sk);