FAILED: patch "[PATCH] mptcp: pm: avoid sending RM_ADDR over same subflow" failed to apply to 5.15-stable tree
Subsystems (3)
[email protected]
maintainerThe patch below does not apply to the 5.15-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 <[email protected]>.
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-5.15.y
git checkout FETCH_HEAD
git cherry-pick -x fb8d0bccb221080630efcd9660c9f9349e53cc9e
# <resolve conflicts, build, test, etc.>
git commit -s
git send-email --to '<[email protected]>' --in-reply-to '2026030907-payday-glaucoma-fe3b@gregkh' --subject-prefix 'PATCH 5.15.y' HEAD^..
Possible dependencies:
thanks,
greg k-h
------------------ original commit in Linus's tree ------------------
From fb8d0bccb221080630efcd9660c9f9349e53cc9e Mon Sep 17 00:00:00 2001
From: "Matthieu Baerts (NGI0)" <[email protected]>
Date: Tue, 3 Mar 2026 11:56:03 +0100
Subject: [PATCH] mptcp: pm: avoid sending RM_ADDR over same subflow
RM_ADDR are sent over an active subflow, the first one in the subflows list. There is then a high chance the initial subflow is picked. With the in-kernel PM, when an endpoint is removed, a RM_ADDR is sent, then linked subflows are closed. This is done for each active MPTCP connection.
MPTCP endpoints are likely removed because the attached network is no longer available or usable. In this case, it is better to avoid sending this RM_ADDR over the subflow that is going to be removed, but prefer sending it over another active and non stale subflow, if any.
This modification avoids situations where the other end is not notified when a subflow is no longer usable: typically when the endpoint linked to the initial subflow is removed, especially on the server side.
net/mptcp/pm.c +43 -12
@@ -212,9 +212,24 @@ void mptcp_pm_send_ack(struct mptcp_sock *msk,spin_lock_bh (&msk->pm.lock); } -void mptcp_pm_addr_send_ack (struct mptcp_sock *msk) +static bool subflow_in_rm_list (const struct mptcp_subflow_context *subflow, +const struct mptcp_rm_list *rm_list) { -struct mptcp_subflow_context *subflow, *alt =NULL ; +u8 i, id =subflow_get_local_id (subflow); + +for (i =0 ; i < rm_list->nr; i++) { +if (rm_list->ids[i] == id) +return true; + } + +return false; +} + +static void +mptcp_pm_addr_send_ack_avoid_list (struct mptcp_sock *msk, +const struct mptcp_rm_list *rm_list) +{ +struct mptcp_subflow_context *subflow, *stale =NULL , *same_id =NULL ;msk_owned_by_me (msk);lockdep_assert_held (&msk->pm.lock);
@@ -224,19 +239,35 @@ void mptcp_pm_addr_send_ack(struct mptcp_sock *msk)return ;mptcp_for_each_subflow (msk, subflow) { -if (__mptcp_subflow_active (subflow)) { -if (!subflow->stale) { -mptcp_pm_send_ack (msk, subflow, false, false); -return ; - } +if (!__mptcp_subflow_active (subflow)) +continue ; -if (!alt) - alt = subflow; +if (unlikely (subflow->stale)) { +if (!stale) + stale = subflow; + }else if (unlikely (rm_list && +subflow_in_rm_list (subflow, rm_list))) { +if (!same_id) + same_id = subflow; + }else { + goto send_ack; } } -if (alt) -mptcp_pm_send_ack (msk, alt, false, false); +if (same_id) + subflow = same_id; +else if (stale) + subflow = stale; +else +return ; + +send_ack: +mptcp_pm_send_ack (msk, subflow, false, false); +} + +void mptcp_pm_addr_send_ack (struct mptcp_sock *msk) +{ +mptcp_pm_addr_send_ack_avoid_list (msk,NULL ); } int mptcp_pm_mp_prio_send_ack(struct mptcp_sock *msk,
@@ -470,7 +501,7 @@ int mptcp_pm_remove_addr(struct mptcp_sock *msk, const struct mptcp_rm_list *rm_ msk->pm.rm_list_tx = *rm_list; rm_addr |=BIT (MPTCP_RM_ADDR_SIGNAL );WRITE_ONCE (msk->pm.addr_signal, rm_addr); -mptcp_pm_addr_send_ack (msk); +mptcp_pm_addr_send_ack_avoid_list (msk, rm_list);return 0 ; }
Sasha Levin
maintainerPATCH 1/1 mptcp: pm: avoid sending RM_ADDR over same subflow
From: "Matthieu Baerts (NGI0)" <[email protected]>
[ Upstream commit fb8d0bccb221080630efcd9660c9f9349e53cc9e ]
RM_ADDR are sent over an active subflow, the first one in the subflows list. There is then a high chance the initial subflow is picked. With the in-kernel PM, when an endpoint is removed, a RM_ADDR is sent, then linked subflows are closed. This is done for each active MPTCP connection.
MPTCP endpoints are likely removed because the attached network is no longer available or usable. In this case, it is better to avoid sending this RM_ADDR over the subflow that is going to be removed, but prefer sending it over another active and non stale subflow, if any.
This modification avoids situations where the other end is not notified when a subflow is no longer usable: typically when the endpoint linked to the initial subflow is removed, especially on the server side.
--- net/mptcp/pm.c | 2 +- net/mptcp/pm_netlink.c | 57 ++++++++++++++++++++++++++++++++++-------- net/mptcp/protocol.h | 2 ++ 3 files changed, 49 insertions(+), 12 deletions(-)
net/mptcp/pm.c +1 -1
@@ -55,7 +55,7 @@ int mptcp_pm_remove_addr(struct mptcp_sock *msk, const struct mptcp_rm_list *rm_ msk->pm.rm_list_tx = *rm_list; rm_addr |=BIT (MPTCP_RM_ADDR_SIGNAL );WRITE_ONCE (msk->pm.addr_signal, rm_addr); -mptcp_pm_nl_addr_send_ack (msk); +mptcp_pm_nl_addr_send_ack_avoid_list (msk, rm_list);return 0 ; }
net/mptcp/pm_netlink.c +46 -11
73 lines not on this page · raw message
net/mptcp/protocol.h +2 -0
@@ -753,6 +753,8 @@ void mptcp_pm_add_addr_send_ack(struct mptcp_sock *msk);bool mptcp_pm_nl_is_init_remote_addr (struct mptcp_sock *msk,const struct mptcp_addr_info *remote);void mptcp_pm_nl_addr_send_ack (struct mptcp_sock *msk); +void mptcp_pm_nl_addr_send_ack_avoid_list (struct mptcp_sock *msk, +const struct mptcp_rm_list *rm_list);void mptcp_pm_rm_addr_received (struct mptcp_sock *msk,const struct mptcp_rm_list *rm_list);void mptcp_pm_mp_prio_received (struct sock *sk,u8 bkup);
Signature · 1 line
2.51.0