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 20D3038D3E8 for ; Thu, 28 May 2026 10:00:05 +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=1779962407; cv=none; b=hkK1IPk6hpo1N4/RKcFYsEcn+wGoVoikas3L/dADizpggu/S8MLbVPindYoGYnKwl56sP2MvIO3JPCBgsWHn+JCjofxIqiMMTpzMIbxCIIU5begb6hcn4orAhXp1hc3rMjQLImkbJysebUzzNS0JiKiNflMq1ZTHhhYyOcY5BDA= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1779962407; c=relaxed/simple; bh=H3NYfp8Jz3ML9bQ2lMyG4DHubOavj1fot9Y+dm3QTfo=; h=Subject:To:Cc:From:Date:Message-ID:MIME-Version:Content-Type; b=J8yx96zb/CMkl8FcWb33e/1htW40i+9HVayDTRr0ghzJ5cHZfXtZ7o0NuepSzY/UyMXdHOk5kIgtGhMf16Da9VbBmeWrmv7r3YZRCBLAf1DeShffXi/Sd3k0zS5C8NrIrI3d5oQGxcIPWZWDNbj/fidJ7A22lBHO47aZoXrOVT8= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b=hIzlDR6T; 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="hIzlDR6T" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 024261F00A3A; Thu, 28 May 2026 10:00:04 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linuxfoundation.org; s=korg; t=1779962405; bh=V1wrUa6RxACH2zM3ujT0V2+eempKRZDOhHSKxJ5zzyA=; h=Subject:To:Cc:From:Date; b=hIzlDR6TnGqaETYVOiqTMfHAaNdF3uZGfhSyjCu58GgNzzPId9r7RLuYbyCm6OLsE JDdBzL3JtW/YGQoNZ8Lek+rh/p6cHUza0pKLLYnnBlLlX5SkCmTyfc57ro/jq7T0CP vgjOz1lyQTQQNhzrgWWvCe5dK6kPNkqqIFiPvxEc= Subject: FAILED: patch "[PATCH] mptcp: pm: fix ADD_ADDR timer infinite retry on option space" failed to apply to 6.1-stable tree To: lixiasong1@huawei.com,matttbe@kernel.org,pabeni@redhat.com Cc: From: Date: Thu, 28 May 2026 11:59:07 +0200 Message-ID: <2026052807-devalue-feast-9d46@gregkh> Precedence: bulk X-Mailing-List: stable@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=ANSI_X3.4-1968 Content-Transfer-Encoding: 8bit The patch below does not apply to the 6.1-stable tree. If someone wants it applied there, or to any other stable or longterm tree, then please email the backport, including the original git commit id to . To reproduce the conflict and resubmit, you may use the following commands: git fetch https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/ linux-6.1.y git checkout FETCH_HEAD git cherry-pick -x 51e398a3b8961b26a8c0a4ba9a777c5339791707 # git commit -s git send-email --to '' --in-reply-to '2026052807-devalue-feast-9d46@gregkh' --subject-prefix 'PATCH 6.1.y' HEAD^.. Possible dependencies: thanks, greg k-h ------------------ original commit in Linus's tree ------------------ >From 51e398a3b8961b26a8c0a4ba9a777c5339791707 Mon Sep 17 00:00:00 2001 From: Li Xiasong Date: Fri, 15 May 2026 06:27:33 +0200 Subject: [PATCH] mptcp: pm: fix ADD_ADDR timer infinite retry on option space insufficient When TCP option space is insufficient (e.g., when sending ADD_ADDR with an IPv6 address and port while tcp_timestamps is enabled), the original code jumped to out_unlock without clearing the addr_signal flag. This caused mptcp_pm_add_timer to keep rescheduling indefinitely, not sending ADD_ADDR, preventing subsequent addresses in the endpoint list from being announced. Handle this case by clearing the ADD_ADDR signal and skipping the matching ADD_ADDR retransmission entry. The skip path cancels the matching timer (with id check) and advances PM state progression, preserving forward progress to subsequent PM work. This cancellation is inherently best-effort. A concurrent add_timer callback may already be running and may acquire pm.lock before the cancel path updates entry state. In that case, one final ADD_ADDR transmit attempt can still be executed. Once the cancel path sets entry->retrans_times to ADD_ADDR_RETRANS_MAX, the callback-side retrans_times check suppresses further ADD_ADDR retransmissions. Note that when an ADD_ADDR is being prepared, a pure-ACK is queued. On the output side, it means that it is fine to skip non-pure-ACK packets, when drop_other_suboptions is set: a pure-ACK will be processed soon after. Fixes: 00cfd77b9063 ("mptcp: retransmit ADD_ADDR when timeout") Cc: stable@vger.kernel.org Signed-off-by: Li Xiasong Reviewed-by: Matthieu Baerts (NGI0) Signed-off-by: Matthieu Baerts (NGI0) Link: https://patch.msgid.link/20260515-net-mptcp-misc-fixes-7-1-rc4-v2-2-701e96419f2f@kernel.org Signed-off-by: Paolo Abeni diff --git a/net/mptcp/pm.c b/net/mptcp/pm.c index 3c152bf66cd5..3e770c7407e1 100644 --- a/net/mptcp/pm.c +++ b/net/mptcp/pm.c @@ -364,7 +364,13 @@ static void mptcp_pm_add_timer(struct timer_list *timer) spin_lock_bh(&msk->pm.lock); - if (!mptcp_pm_should_add_signal_addr(msk)) { + /* The cancel path (mptcp_pm_del_add_timer()) can race with this + * callback. Once cancel updates retrans_times to MAX, suppress further + * retransmissions here. If this callback acquires pm.lock first, one + * final transmit attempt is still possible. + */ + if (entry->retrans_times < ADD_ADDR_RETRANS_MAX && + !mptcp_pm_should_add_signal_addr(msk)) { pr_debug("retransmit ADD_ADDR id=%d\n", entry->addr.id); mptcp_pm_announce_addr(msk, &entry->addr, false); mptcp_pm_add_addr_send_ack(msk); @@ -414,8 +420,12 @@ mptcp_pm_del_add_timer(struct mptcp_sock *msk, /* Note: entry might have been removed by another thread. * We hold rcu_read_lock() to ensure it is not freed under us. */ - if (stop_timer) - sk_stop_timer_sync(sk, &entry->add_timer); + if (stop_timer) { + if (check_id) + sk_stop_timer(sk, &entry->add_timer); + else + sk_stop_timer_sync(sk, &entry->add_timer); + } rcu_read_unlock(); return entry; @@ -882,6 +892,7 @@ bool mptcp_pm_add_addr_signal(struct mptcp_sock *msk, const struct sk_buff *skb, struct mptcp_addr_info *addr, bool *echo, bool *drop_other_suboptions) { + bool skip_add_addr = false; int ret = false; u8 add_addr; u8 family; @@ -903,24 +914,49 @@ bool mptcp_pm_add_addr_signal(struct mptcp_sock *msk, const struct sk_buff *skb, } *echo = mptcp_pm_should_add_signal_echo(msk); - port = !!(*echo ? msk->pm.remote.port : msk->pm.local.port); - - family = *echo ? msk->pm.remote.family : msk->pm.local.family; - if (remaining < mptcp_add_addr_len(family, *echo, port)) - goto out_unlock; - if (*echo) { *addr = msk->pm.remote; add_addr = msk->pm.addr_signal & ~BIT(MPTCP_ADD_ADDR_ECHO); + port = !!msk->pm.remote.port; + family = msk->pm.remote.family; } else { *addr = msk->pm.local; add_addr = msk->pm.addr_signal & ~BIT(MPTCP_ADD_ADDR_SIGNAL); + port = !!msk->pm.local.port; + family = msk->pm.local.family; } - WRITE_ONCE(msk->pm.addr_signal, add_addr); + + if (remaining < mptcp_add_addr_len(family, *echo, port)) { + struct net *net = sock_net((struct sock *)msk); + + if (!*drop_other_suboptions) + goto out_unlock; + + if (*echo) { + MPTCP_INC_STATS(net, MPTCP_MIB_ECHOADDTXDROP); + } else { + skip_add_addr = true; + MPTCP_INC_STATS(net, MPTCP_MIB_ADDADDRTXDROP); + } + goto drop_signal_mark; + } + ret = true; +drop_signal_mark: + WRITE_ONCE(msk->pm.addr_signal, add_addr); + out_unlock: spin_unlock_bh(&msk->pm.lock); + + /* On pure-ACK option-space exhaustion, stop retrying this ADD_ADDR: + * clear the signal bit, cancel the matching retransmission timer, and + * let the PM state machine progress. + */ + if (skip_add_addr) { + mptcp_pm_del_add_timer(msk, addr, true); + mptcp_pm_subflow_established(msk); + } return ret; }