If no subflow is attached to the 'signal' endpoint that is being
removed, the addr ID will not be marked as available again.

Mark the linked ID as available when removing the address entry from the
list to cover this case.

Fixes: b6c08380860b ("mptcp: remove addr and subflow in PM netlink")
Signed-off-by: Matthieu Baerts (NGI0) <matttbe@kernel.org>
---
 net/mptcp/pm_netlink.c | 5 +++++
 1 file changed, 5 insertions(+)

diff --git a/net/mptcp/pm_netlink.c b/net/mptcp/pm_netlink.c
index 2e94f2a9f2a6..d44d318dce03 100644
--- a/net/mptcp/pm_netlink.c
+++ b/net/mptcp/pm_netlink.c
@@ -1394,6 +1394,11 @@ static bool remove_anno_list_by_saddr(struct mptcp_sock *msk,
 
 	entry = mptcp_pm_del_add_timer(msk, addr, false);
 	if (entry) {
+		spin_lock_bh(&msk->pm.lock);
+		__set_bit(entry->addr.id ? : msk->mpc_endpoint_id,
+			  msk->pm.id_avail_bitmap);
+		spin_unlock_bh(&msk->pm.lock);
+
 		list_del(&entry->list);
 		kfree(entry);
 		return true;

-- 
2.45.2