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 95A3F330B2D; Thu, 28 May 2026 19:58:03 +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=1779998284; cv=none; b=ouVvmQQCJWt2REFEm6yrMfS6xSmYPXeKWRZySMOPnkDy1O8jpfFZZuuxR/eSX02UPP0dfR5leBpYE8uUCFiAcjN8gp68mxDfrYpkNzdl4CJOqjcSBKOh2nvG5Z/0WHLmiuQ8+U37pLT1lXnOVu5Eh9MJvNeTNlP5nYFlX6yjVAk= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1779998284; c=relaxed/simple; bh=sRDjgwfXHRXZW42Yy9PWjjmsNt/mDk14Nu26FTSGFyI=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=XxN5BE5kjs75NTgsvdRRf9dbBnCGe3ua53wiG/yNO2Nz21Uo49j5y/bV+RSsE29qKFyqlT9mdFMEr9tjwnmdmgvFnrVd3wJfDJm6vAto1muuzzurXl3SsMUTY93nwx2/SrjCWG3MnbBucdHO7NqJzBN3uTTVS2AD9w1yPoAdNRE= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b=zzyU362X; 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="zzyU362X" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 009DF1F000E9; Thu, 28 May 2026 19:58:02 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linuxfoundation.org; s=korg; t=1779998283; bh=4xfVPEEfF9vYQMn0akKw+TZFfUOgXBJbo/itvGDE2Z4=; h=From:To:Cc:Subject:Date:In-Reply-To:References; b=zzyU362X2XDvoLvKDhLC6m1fhP+W5vmX6DrJ+1NRAzoZt2eRFb80pJHXVLLEvzIjf GS5S7Mztw+PiOoH5ja5SCjXxbIU51nIbut3diMRUFNSFhF6qZ3mZhiy8gWD4FHykSf SkaXvoLiztcyeMPqBrwqv3MNKZKa33Pp2/BkhpPE= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, Shardul Bankar , Paolo Abeni , "Matthieu Baerts (NGI0)" Subject: [PATCH 7.0 083/461] mptcp: do not drop partial packets Date: Thu, 28 May 2026 21:43:32 +0200 Message-ID: <20260528194649.321344411@linuxfoundation.org> X-Mailer: git-send-email 2.54.0 In-Reply-To: <20260528194646.819809818@linuxfoundation.org> References: <20260528194646.819809818@linuxfoundation.org> User-Agent: quilt/0.69 X-stable: review X-Patchwork-Hint: ignore Precedence: bulk X-Mailing-List: stable@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit 7.0-stable review patch. If anyone has any objections, please let me know. ------------------ From: Shardul Bankar commit 50c2d91c5dfa0e465826ec1f8dbad9cdc254bd85 upstream. When a packet arrives with map_seq < ack_seq < end_seq, the beginning of the packet has already been acknowledged but the end contains new data. Currently the entire packet is dropped as "old data," forcing the sender to retransmit. Instead, skip the already-acked bytes by adjusting the skb offset and enqueue only the new portion. Update bytes_received and ack_seq to reflect the new data consumed. A previous attempt at this fix has been sent by Paolo Abeni [1], but had issues [2]: it also added a zero-window check and changed rcv_wnd_sent initialization, which caused test regressions. This version addresses only the partial packet handling without modifying receive window accounting. Fixes: ab174ad8ef76 ("mptcp: move ooo skbs into msk out of order queue.") Cc: stable@vger.kernel.org Link: https://lore.kernel.org/c9b426a4e163aa3c4fe8b80c79f1a610f47ae7d8.1763075056.git.pabeni@redhat.com [1] Closes: https://github.com/multipath-tcp/mptcp_net-next/issues/600 [2] Signed-off-by: Shardul Bankar [pabeni@redhat.com: update map] Signed-off-by: Paolo Abeni Reviewed-by: Matthieu Baerts (NGI0) Signed-off-by: Matthieu Baerts (NGI0) Link: https://patch.msgid.link/20260515-net-mptcp-misc-fixes-7-1-rc4-v2-1-701e96419f2f@kernel.org Signed-off-by: Paolo Abeni Signed-off-by: Greg Kroah-Hartman --- net/mptcp/protocol.c | 24 +++++++++++++++++++----- 1 file changed, 19 insertions(+), 5 deletions(-) --- a/net/mptcp/protocol.c +++ b/net/mptcp/protocol.c @@ -397,12 +397,26 @@ static bool __mptcp_move_skb(struct sock return false; } - /* old data, keep it simple and drop the whole pkt, sender - * will retransmit as needed, if needed. + /* Completely old data? */ + if (!after64(MPTCP_SKB_CB(skb)->end_seq, msk->ack_seq)) { + MPTCP_INC_STATS(sock_net(sk), MPTCP_MIB_DUPDATA); + mptcp_drop(sk, skb); + return false; + } + + /* Partial packet: map_seq < ack_seq < end_seq. + * Skip the already-acked bytes and enqueue the new data. */ - MPTCP_INC_STATS(sock_net(sk), MPTCP_MIB_DUPDATA); - mptcp_drop(sk, skb); - return false; + copy_len = MPTCP_SKB_CB(skb)->end_seq - msk->ack_seq; + MPTCP_SKB_CB(skb)->offset += msk->ack_seq - MPTCP_SKB_CB(skb)->map_seq; + MPTCP_SKB_CB(skb)->map_seq += msk->ack_seq - + MPTCP_SKB_CB(skb)->map_seq; + msk->bytes_received += copy_len; + WRITE_ONCE(msk->ack_seq, msk->ack_seq + copy_len); + + skb_set_owner_r(skb, sk); + __skb_queue_tail(&sk->sk_receive_queue, skb); + return true; } static void mptcp_stop_rtx_timer(struct sock *sk)