diff --git a/net/mptcp/pm.c b/net/mptcp/pm.c
index 55406720c60711..98b0b31e3b8d59 100644
--- a/net/mptcp/pm.c
+++ b/net/mptcp/pm.c
@@ -405,7 +405,8 @@ bool mptcp_pm_rm_addr_signal(struct mptcp_sock *msk, unsigned int remaining,
 	return ret;
 }
 
-int mptcp_pm_get_local_id(struct mptcp_sock *msk, struct sock_common *skc)
+int mptcp_pm_get_local_id(struct mptcp_sock *msk, struct sock_common *skc,
+			  bool *backup)
 {
 	struct mptcp_addr_info skc_local;
 	struct mptcp_addr_info msk_local;
@@ -413,6 +414,8 @@ int mptcp_pm_get_local_id(struct mptcp_sock *msk, struct sock_common *skc)
 	if (WARN_ON_ONCE(!msk))
 		return -1;
 
+	*backup = false;
+
 	/* The 0 ID mapping is defined by the first subflow, copied into the msk
 	 * addr
 	 */
@@ -422,8 +425,8 @@ int mptcp_pm_get_local_id(struct mptcp_sock *msk, struct sock_common *skc)
 		return 0;
 
 	if (mptcp_pm_is_userspace(msk))
-		return mptcp_userspace_pm_get_local_id(msk, &skc_local);
-	return mptcp_pm_nl_get_local_id(msk, &skc_local);
+		return mptcp_userspace_pm_get_local_id(msk, &skc_local, backup);
+	return mptcp_pm_nl_get_local_id(msk, &skc_local, backup);
 }
 
 int mptcp_pm_get_flags_and_ifindex_by_id(struct mptcp_sock *msk, unsigned int id,
diff --git a/net/mptcp/pm_netlink.c b/net/mptcp/pm_netlink.c
index 7635fac9153989..44bfab3516937d 100644
--- a/net/mptcp/pm_netlink.c
+++ b/net/mptcp/pm_netlink.c
@@ -1064,7 +1064,8 @@ static int mptcp_pm_nl_create_listen_socket(struct sock *sk,
 	return err;
 }
 
-int mptcp_pm_nl_get_local_id(struct mptcp_sock *msk, struct mptcp_addr_info *skc)
+int mptcp_pm_nl_get_local_id(struct mptcp_sock *msk, struct mptcp_addr_info *skc,
+			     bool *backup)
 {
 	struct mptcp_pm_addr_entry *entry;
 	struct pm_nl_pernet *pernet;
@@ -1076,6 +1077,7 @@ int mptcp_pm_nl_get_local_id(struct mptcp_sock *msk, struct mptcp_addr_info *skc
 	list_for_each_entry_rcu(entry, &pernet->local_addr_list, list) {
 		if (mptcp_addresses_equal(&entry->addr, skc, entry->addr.port)) {
 			ret = entry->addr.id;
+			*backup = !!(entry->flags & MPTCP_PM_ADDR_FLAG_BACKUP);
 			break;
 		}
 	}
diff --git a/net/mptcp/pm_userspace.c b/net/mptcp/pm_userspace.c
index f0a4590506c69a..adc015af168ea7 100644
--- a/net/mptcp/pm_userspace.c
+++ b/net/mptcp/pm_userspace.c
@@ -137,7 +137,7 @@ int mptcp_userspace_pm_get_flags_and_ifindex_by_id(struct mptcp_sock *msk,
 }
 
 int mptcp_userspace_pm_get_local_id(struct mptcp_sock *msk,
-				    struct mptcp_addr_info *skc)
+				    struct mptcp_addr_info *skc, bool *backup)
 {
 	struct mptcp_pm_addr_entry *entry = NULL, *e, new_entry;
 	__be16 msk_sport =  ((struct inet_sock *)
@@ -151,8 +151,10 @@ int mptcp_userspace_pm_get_local_id(struct mptcp_sock *msk,
 		}
 	}
 	spin_unlock_bh(&msk->pm.lock);
-	if (entry)
+	if (entry) {
+		*backup = !!(entry->flags & MPTCP_PM_ADDR_FLAG_BACKUP);
 		return entry->addr.id;
+	}
 
 	memset(&new_entry, 0, sizeof(struct mptcp_pm_addr_entry));
 	new_entry.addr = *skc;
diff --git a/net/mptcp/protocol.h b/net/mptcp/protocol.h
index 6b6b76152db52a..cee0a8098b4160 100644
--- a/net/mptcp/protocol.h
+++ b/net/mptcp/protocol.h
@@ -1111,9 +1111,12 @@ bool mptcp_pm_add_addr_signal(struct mptcp_sock *msk, const struct sk_buff *skb,
 			      bool *drop_other_suboptions);
 bool mptcp_pm_rm_addr_signal(struct mptcp_sock *msk, unsigned int remaining,
 			     struct mptcp_rm_list *rm_list);
-int mptcp_pm_get_local_id(struct mptcp_sock *msk, struct sock_common *skc);
-int mptcp_pm_nl_get_local_id(struct mptcp_sock *msk, struct mptcp_addr_info *skc);
-int mptcp_userspace_pm_get_local_id(struct mptcp_sock *msk, struct mptcp_addr_info *skc);
+int mptcp_pm_get_local_id(struct mptcp_sock *msk, struct sock_common *skc,
+			  bool *backup);
+int mptcp_pm_nl_get_local_id(struct mptcp_sock *msk, struct mptcp_addr_info *skc,
+			     bool *backup);
+int mptcp_userspace_pm_get_local_id(struct mptcp_sock *msk, struct mptcp_addr_info *skc,
+				    bool *backup);
 int mptcp_pm_dump_addr(struct sk_buff *msg, struct netlink_callback *cb);
 int mptcp_pm_nl_dump_addr(struct sk_buff *msg,
 			  struct netlink_callback *cb);
diff --git a/net/mptcp/subflow.c b/net/mptcp/subflow.c
index a3778aee4e77f8..955fb9aa2ce528 100644
--- a/net/mptcp/subflow.c
+++ b/net/mptcp/subflow.c
@@ -87,6 +87,7 @@ static struct mptcp_sock *subflow_token_join_request(struct request_sock *req)
 	struct mptcp_subflow_request_sock *subflow_req = mptcp_subflow_rsk(req);
 	struct mptcp_sock *msk;
 	int local_id;
+	bool backup;
 
 	msk = mptcp_token_get_sock(sock_net(req_to_sk(req)), subflow_req->token);
 	if (!msk) {
@@ -94,12 +95,13 @@ static struct mptcp_sock *subflow_token_join_request(struct request_sock *req)
 		return NULL;
 	}
 
-	local_id = mptcp_pm_get_local_id(msk, (struct sock_common *)req);
+	local_id = mptcp_pm_get_local_id(msk, (struct sock_common *)req, &backup);
 	if (local_id < 0) {
 		sock_put((struct sock *)msk);
 		return NULL;
 	}
 	subflow_req->local_id = local_id;
+	subflow_req->request_bkup = backup;
 
 	return msk;
 }
@@ -604,12 +606,13 @@ static int subflow_chk_local_id(struct sock *sk)
 {
 	struct mptcp_subflow_context *subflow = mptcp_subflow_ctx(sk);
 	struct mptcp_sock *msk = mptcp_sk(subflow->conn);
+	bool backup;
 	int err;
 
 	if (likely(subflow->local_id >= 0))
 		return 0;
 
-	err = mptcp_pm_get_local_id(msk, (struct sock_common *)sk);
+	err = mptcp_pm_get_local_id(msk, (struct sock_common *)sk, &backup);
 	if (err < 0)
 		return err;
 
diff --git a/tools/testing/selftests/net/mptcp/mptcp_join.sh b/tools/testing/selftests/net/mptcp/mptcp_join.sh
index 55d84a1bde15de..167914df05fa8e 100755
--- a/tools/testing/selftests/net/mptcp/mptcp_join.sh
+++ b/tools/testing/selftests/net/mptcp/mptcp_join.sh
@@ -2617,6 +2617,19 @@ backup_tests()
 
 	# single address, backup
 	if reset "single address, backup" &&
+	   continue_if mptcp_lib_kallsyms_has "subflow_rebuild_header$"; then
+		pm_nl_set_limits $ns1 0 1
+		pm_nl_add_endpoint $ns1 10.0.2.1 flags signal,backup
+		pm_nl_set_limits $ns2 1 1
+		sflags=nobackup speed=slow \
+			run_tests $ns1 $ns2 10.0.1.1
+		chk_join_nr 1 1 1
+		chk_add_nr 1 1
+		chk_prio_nr 1 0
+	fi
+
+	# single address, switch to backup
+	if reset "single address, switch to backup" &&
 	   continue_if mptcp_lib_kallsyms_has "subflow_rebuild_header$"; then
 		pm_nl_set_limits $ns1 0 1
 		pm_nl_add_endpoint $ns1 10.0.2.1 flags signal
@@ -2632,13 +2645,13 @@ backup_tests()
 	if reset "single address with port, backup" &&
 	   continue_if mptcp_lib_kallsyms_has "subflow_rebuild_header$"; then
 		pm_nl_set_limits $ns1 0 1
-		pm_nl_add_endpoint $ns1 10.0.2.1 flags signal port 10100
+		pm_nl_add_endpoint $ns1 10.0.2.1 flags signal,backup port 10100
 		pm_nl_set_limits $ns2 1 1
-		sflags=backup speed=slow \
+		sflags=nobackup speed=slow \
 			run_tests $ns1 $ns2 10.0.1.1
 		chk_join_nr 1 1 1
 		chk_add_nr 1 1
-		chk_prio_nr 1 1
+		chk_prio_nr 1 0
 	fi
 
 	if reset "mpc backup" &&