Merge tag 'trace-v7.3-2' of git://git.kernel.org/pub/scm/linux/kernel/git/trace/linux-tracegrafted

Pull tracing fixes from Steven Rostedt:

 - Fix error output of boot instance creation failure

   Currently if a boot instance creation fails, instead of printing out
   the name of the instance that failed, it prints "(null)". That is
   because it prints "cur_str" that had already been processed by
   strsep(). Print the saved name instead.

   While at it, print the error code of the failure.

 - Fix use-after-free for same named historgrams

   Histograms can be named so that they can be used in multiple events.
   But if the named histogram has a variable attached, the second event
   that uses the named histogram which duplicates it and needs to free
   the original after duplication leaves the old variable in place and
   still visible. If another histogram uses than variable, it will use
   the stale one which will try to reference the freed duplicate
   histogram and crash the kernel.

   Free the duplicate variables along with the duplicated histogram
   data.

 - Check return value of kthread_run() in event self test

   The events self tests uses a kthread for testing but does not check
   if it succeeded in creating a kthread. If the kthread creation were
   to fail, the code will still try to call kthread_stop() on the error
   returned.

 - Fix race between reading trace_pipe and updating subbuffer size

   If a user is reading the trace_pipe file at the same time they update
   the ring buffer sub-buffer size, can cause the trace_pipe read to
   read stale data. Add trace_access_lock() around updating the ring
   buffer sub-buffer size.

 - Fix eventfs_inode on failure path in creation of the events directory

   In the creation of the "events" directory, if after allocating the
   eventfs_inode a failure is detected, it calls cleanup_ei() which
   calls free_ei(). The free_ei() will test if eventfs_inode being freed
   has no children. It is a bug if it does. But on the failure case of
   the creation of the "events" directory, the children lists have not
   yet been initialized and the free will trigger a warning because
   list_empty() on an uninitialized list returns false.

   Move the initialization into init_ei() where it makes more sense and
   makes sure that a created eventfs_inode has its lists initialized
   upon creation.

 - Check return value of kthread_run() in ftrace direct sample code

   The sample code that shows how to use the ftrace direct calls does
   not test the return of kthread_run() to see if it succeeds. Return a
   failure if the kthread_run() doesn't succeed.

 - Clear user events state on fork in case of alloc failure

   On fork, the child gets a pointer to the parent's user events state.
   It makes a copy of it then updates the child's pointer to it. But if
   the allocation fails, the duplication function leaves the child with
   a pointer to its parent's descriptor. When the child cleans up its
   data, it will free the parent's descriptor while the parent is still
   using it.

   In the duplication function, set the child's user_event_mm to NULL
   before testing if the allocation succeeded, and when it exits it will
   not free the parent's descriptor.

 - Fix retry exhaustion in simple ring buffer reader swap

   simple_ring_buffer_swap_reader_page() starts with retry set to 8 and
   post-decrements it only after a failed link replacement. On the final
   attempt, a successful replacement leaves retry at zero, while a
   failed replacement leaves it at -1.

   But the check for success expects the retry value to be non-zero and
   exits with an error on zero. This is the opposite result. Fix it.

 - Fail nicely when the remote swap_reader_page() returns an error

   Currently, if the swap_reader_page() of a remote buffer fails, it
   triggers a WARN_ON_ONCE() and continues normally. Instead, have it
   exit with an error and a pr_warn() print instead of a full WARNING.

* tag 'trace-v7.3-2' of git://git.kernel.org/pub/scm/linux/kernel/git/trace/linux-trace:
  ring-buffer: Stop remote reader update when page swap fails
  tracing: Fix retry exhaustion in simple ring buffer reader swap
  tracing/user_events: Clear copied tracing state before fork duplication
  samples/ftrace: Fix kthread_stop() on ERR_PTR in ftrace-direct-multi-modify
  samples/ftrace: Fix kthread_stop() on ERR_PTR in ftrace-direct-modify
  eventfs: Initialize ei->children and ei->list in init_ei()
  tracing: Fix use-after-free in trace_pipe read on sub-buffer order change
  tracing: Fix crash passing ERR_PTR to kthread_stop()
  tracing: Fix use-after-free with same-name named triggers
  tracing: Fix logged instance name on creation failure

1 files changed, 708 insertions, 0 deletions

diff --git a/net/mptcp/pm_userspace.c b/net/mptcp/pm_userspace.c
new file mode 100644
index 000000000..b94fbb483
--- /dev/null
+++ b/net/mptcp/pm_userspace.c
@@ -0,0 +1,708 @@
+// SPDX-License-Identifier: GPL-2.0
+/* Multipath TCP
+ *
+ * Copyright (c) 2022, Intel Corporation.
+ */
+
+#include "protocol.h"
+#include "mib.h"
+#include "mptcp_pm_gen.h"
+
+#define mptcp_for_each_userspace_pm_addr(__msk, __entry)			\
+	list_for_each_entry(__entry,						\
+			    &((__msk)->pm.userspace_pm_local_addr_list), list)
+
+void mptcp_userspace_pm_free_local_addr_list(struct mptcp_sock *msk)
+{
+	struct mptcp_pm_addr_entry *entry, *tmp;
+	struct sock *sk = (struct sock *)msk;
+	LIST_HEAD(free_list);
+
+	spin_lock_bh(&msk->pm.lock);
+	list_splice_init(&msk->pm.userspace_pm_local_addr_list, &free_list);
+	spin_unlock_bh(&msk->pm.lock);
+
+	list_for_each_entry_safe(entry, tmp, &free_list, list) {
+		sock_kfree_s(sk, entry, sizeof(*entry));
+	}
+}
+
+static struct mptcp_pm_addr_entry *
+mptcp_userspace_pm_lookup_addr(struct mptcp_sock *msk,
+			       const struct mptcp_addr_info *addr)
+{
+	struct mptcp_pm_addr_entry *entry;
+
+	mptcp_for_each_userspace_pm_addr(msk, entry) {
+		if (mptcp_addresses_equal(&entry->addr, addr, false))
+			return entry;
+	}
+	return NULL;
+}
+
+static int mptcp_userspace_pm_append_new_local_addr(struct mptcp_sock *msk,
+						    struct mptcp_pm_addr_entry *entry,
+						    bool needs_id)
+{
+	DECLARE_BITMAP(id_bitmap, MPTCP_PM_MAX_ADDR_ID + 1);
+	struct sock *sk = (struct sock *)msk;
+	struct mptcp_pm_addr_entry *e;
+	bool addr_match = false;
+	bool id_match = false;
+	int ret = -EINVAL;
+
+	bitmap_zero(id_bitmap, MPTCP_PM_MAX_ADDR_ID + 1);
+
+	spin_lock_bh(&msk->pm.lock);
+	if (msk->pm.status & BIT(MPTCP_PM_DESTROYING)) {
+		ret = -EINVAL;
+		goto append_err;
+	}
+	mptcp_for_each_userspace_pm_addr(msk, e) {
+		addr_match = mptcp_addresses_equal(&e->addr, &entry->addr, true);
+		if (addr_match && entry->addr.id == 0 && needs_id)
+			entry->addr.id = e->addr.id;
+		id_match = (e->addr.id == entry->addr.id);
+		if (addr_match || id_match)
+			break;
+		__set_bit(e->addr.id, id_bitmap);
+	}
+
+	if (!addr_match && !id_match) {
+		/* Memory for the entry is allocated from the
+		 * sock option buffer.
+		 */
+		e = sock_kmemdup(sk, entry, sizeof(*entry), GFP_ATOMIC);
+		if (!e) {
+			ret = -ENOMEM;
+			goto append_err;
+		}
+
+		if (!e->addr.id && needs_id)
+			e->addr.id = find_next_zero_bit(id_bitmap,
+							MPTCP_PM_MAX_ADDR_ID + 1,
+							1);
+		list_add_tail_rcu(&e->list, &msk->pm.userspace_pm_local_addr_list);
+		msk->pm.local_addr_used++;
+		ret = e->addr.id;
+	} else if (addr_match && id_match) {
+		ret = entry->addr.id;
+	}
+
+append_err:
+	spin_unlock_bh(&msk->pm.lock);
+	return ret;
+}
+
+/* If the subflow is closed from the other peer (not via a
+ * subflow destroy command then), we want to keep the entry
+ * not to assign the same ID to another address and to be
+ * able to send RM_ADDR after the removal of the subflow.
+ */
+static int mptcp_userspace_pm_delete_local_addr(struct mptcp_sock *msk,
+						struct mptcp_pm_addr_entry *addr)
+{
+	struct sock *sk = (struct sock *)msk;
+	struct mptcp_pm_addr_entry *entry;
+
+	entry = mptcp_userspace_pm_lookup_addr(msk, &addr->addr);
+	if (!entry)
+		return -EINVAL;
+
+	/* TODO: a refcount is needed because the entry can
+	 * be used multiple times (e.g. fullmesh mode).
+	 */
+	list_del_rcu(&entry->list);
+	sock_kfree_s(sk, entry, sizeof(*entry));
+	msk->pm.local_addr_used--;
+	return 0;
+}
+
+static struct mptcp_pm_addr_entry *
+mptcp_userspace_pm_lookup_addr_by_id(struct mptcp_sock *msk, unsigned int id)
+{
+	struct mptcp_pm_addr_entry *entry;
+
+	mptcp_for_each_userspace_pm_addr(msk, entry) {
+		if (entry->addr.id == id)
+			return entry;
+	}
+	return NULL;
+}
+
+int mptcp_userspace_pm_get_local_id(struct mptcp_sock *msk,
+				    struct mptcp_pm_addr_entry *skc)
+{
+	__be16 msk_sport =  ((struct inet_sock *)
+			     inet_sk((struct sock *)msk))->inet_sport;
+	struct mptcp_pm_addr_entry *entry;
+	int id;
+
+	spin_lock_bh(&msk->pm.lock);
+	entry = mptcp_userspace_pm_lookup_addr(msk, &skc->addr);
+	id = entry ? entry->addr.id : -1;
+	spin_unlock_bh(&msk->pm.lock);
+
+	if (id != -1)
+		return id;
+
+	if (skc->addr.port == msk_sport)
+		skc->addr.port = 0;
+
+	return mptcp_userspace_pm_append_new_local_addr(msk, skc, true);
+}
+
+bool mptcp_userspace_pm_is_backup(struct mptcp_sock *msk,
+				  struct mptcp_addr_info *skc)
+{
+	struct mptcp_pm_addr_entry *entry;
+	bool backup;
+
+	spin_lock_bh(&msk->pm.lock);
+	entry = mptcp_userspace_pm_lookup_addr(msk, skc);
+	backup = entry && !!(entry->flags & MPTCP_PM_ADDR_FLAG_BACKUP);
+	spin_unlock_bh(&msk->pm.lock);
+
+	return backup;
+}
+
+static struct mptcp_sock *mptcp_userspace_pm_get_sock(const struct genl_info *info)
+{
+	struct mptcp_sock *msk;
+	struct nlattr *token;
+
+	if (GENL_REQ_ATTR_CHECK(info, MPTCP_PM_ATTR_TOKEN))
+		return NULL;
+
+	token = info->attrs[MPTCP_PM_ATTR_TOKEN];
+	msk = mptcp_token_get_sock(genl_info_net(info), nla_get_u32(token));
+	if (!msk) {
+		NL_SET_ERR_MSG_ATTR(info->extack, token, "invalid token");
+		return NULL;
+	}
+
+	if (!mptcp_pm_is_userspace(msk)) {
+		NL_SET_ERR_MSG_ATTR(info->extack, token,
+				    "userspace PM not selected");
+		sock_put((struct sock *)msk);
+		return NULL;
+	}
+
+	return msk;
+}
+
+int mptcp_pm_nl_announce_doit(struct sk_buff *skb, struct genl_info *info)
+{
+	struct mptcp_pm_addr_entry addr_val;
+	struct mptcp_sock *msk;
+	struct nlattr *addr;
+	int err = -EINVAL;
+	struct sock *sk;
+
+	if (GENL_REQ_ATTR_CHECK(info, MPTCP_PM_ATTR_ADDR))
+		return err;
+
+	msk = mptcp_userspace_pm_get_sock(info);
+	if (!msk)
+		return err;
+
+	sk = (struct sock *)msk;
+
+	addr = info->attrs[MPTCP_PM_ATTR_ADDR];
+	err = mptcp_pm_parse_entry(addr, info, true, &addr_val);
+	if (err < 0)
+		goto announce_err;
+
+	if (addr_val.addr.id == 0) {
+		NL_SET_ERR_MSG_ATTR(info->extack, addr, "invalid addr id");
+		err = -EINVAL;
+		goto announce_err;
+	}
+
+	if (!(addr_val.flags & MPTCP_PM_ADDR_FLAG_SIGNAL)) {
+		NL_SET_ERR_MSG_ATTR(info->extack, addr, "invalid addr flags");
+		err = -EINVAL;
+		goto announce_err;
+	}
+
+	err = mptcp_userspace_pm_append_new_local_addr(msk, &addr_val, false);
+	if (err < 0) {
+		NL_SET_ERR_MSG_ATTR(info->extack, addr,
+				    "did not match address and id");
+		goto announce_err;
+	}
+
+	lock_sock(sk);
+	spin_lock_bh(&msk->pm.lock);
+
+	if (mptcp_pm_announced_alloc(msk, &addr_val.addr)) {
+		msk->pm.add_addr_signaled++;
+		mptcp_pm_announce_addr(msk, &addr_val.addr, false);
+		mptcp_pm_addr_send_ack(msk);
+	}
+
+	spin_unlock_bh(&msk->pm.lock);
+	release_sock(sk);
+
+	err = 0;
+ announce_err:
+	sock_put(sk);
+	return err;
+}
+
+static int mptcp_userspace_pm_remove_id_zero_address(struct mptcp_sock *msk)
+{
+	struct mptcp_rm_list list = { .nr = 0 };
+	struct mptcp_subflow_context *subflow;
+	struct sock *sk = (struct sock *)msk;
+	bool has_id_0 = false;
+	int err = -EINVAL;
+
+	lock_sock(sk);
+	mptcp_for_each_subflow(msk, subflow) {
+		if (READ_ONCE(subflow->local_id) == 0) {
+			has_id_0 = true;
+			break;
+		}
+	}
+	if (!has_id_0)
+		goto remove_err;
+
+	list.ids[list.nr++] = 0;
+
+	spin_lock_bh(&msk->pm.lock);
+	mptcp_pm_remove_addr(msk, &list);
+	spin_unlock_bh(&msk->pm.lock);
+
+	err = 0;
+
+remove_err:
+	release_sock(sk);
+	return err;
+}
+
+static void
+mptcp_userspace_pm_remove_addr_entry(struct mptcp_sock *msk,
+				     struct mptcp_pm_addr_entry *entry)
+{
+	struct mptcp_rm_list alist = { .nr = 0 };
+	int anno_nr = 0;
+
+	/* only delete if either announced or matching a subflow */
+	if (mptcp_pm_announced_remove(msk, &entry->addr))
+		anno_nr++;
+	else if (!mptcp_pm_has_subflow_saddr(msk, &entry->addr))
+		return;
+
+	alist.ids[alist.nr++] = entry->addr.id;
+
+	spin_lock_bh(&msk->pm.lock);
+	msk->pm.add_addr_signaled -= anno_nr;
+	mptcp_pm_remove_addr(msk, &alist);
+	spin_unlock_bh(&msk->pm.lock);
+}
+
+int mptcp_pm_nl_remove_doit(struct sk_buff *skb, struct genl_info *info)
+{
+	struct mptcp_pm_addr_entry *match;
+	struct mptcp_sock *msk;
+	struct nlattr *id;
+	int err = -EINVAL;
+	struct sock *sk;
+	u8 id_val;
+
+	if (GENL_REQ_ATTR_CHECK(info, MPTCP_PM_ATTR_LOC_ID))
+		return err;
+
+	id = info->attrs[MPTCP_PM_ATTR_LOC_ID];
+	id_val = nla_get_u8(id);
+
+	msk = mptcp_userspace_pm_get_sock(info);
+	if (!msk)
+		return err;
+
+	sk = (struct sock *)msk;
+
+	if (id_val == 0) {
+		err = mptcp_userspace_pm_remove_id_zero_address(msk);
+		goto out;
+	}
+
+	lock_sock(sk);
+
+	spin_lock_bh(&msk->pm.lock);
+	match = mptcp_userspace_pm_lookup_addr_by_id(msk, id_val);
+	if (!match) {
+		spin_unlock_bh(&msk->pm.lock);
+		release_sock(sk);
+		goto out;
+	}
+
+	list_del_rcu(&match->list);
+	spin_unlock_bh(&msk->pm.lock);
+
+	mptcp_userspace_pm_remove_addr_entry(msk, match);
+
+	release_sock(sk);
+
+	kfree_rcu_mightsleep(match);
+	/* Adjust sk_omem_alloc like sock_kfree_s() does, to match
+	 * with allocation of this memory by sock_kmemdup()
+	 */
+	atomic_sub(sizeof(*match), &sk->sk_omem_alloc);
+
+	err = 0;
+out:
+	if (err)
+		NL_SET_ERR_MSG_ATTR_FMT(info->extack, id,
+					"address with id %u not found",
+					id_val);
+
+	sock_put(sk);
+	return err;
+}
+
+int mptcp_pm_nl_subflow_create_doit(struct sk_buff *skb, struct genl_info *info)
+{
+	struct mptcp_pm_addr_entry entry = { 0 };
+	struct mptcp_addr_info addr_r;
+	struct nlattr *raddr, *laddr;
+	struct mptcp_pm_local local;
+	struct mptcp_sock *msk;
+	int err = -EINVAL;
+	struct sock *sk;
+
+	if (GENL_REQ_ATTR_CHECK(info, MPTCP_PM_ATTR_ADDR) ||
+	    GENL_REQ_ATTR_CHECK(info, MPTCP_PM_ATTR_ADDR_REMOTE))
+		return err;
+
+	msk = mptcp_userspace_pm_get_sock(info);
+	if (!msk)
+		return err;
+
+	sk = (struct sock *)msk;
+
+	laddr = info->attrs[MPTCP_PM_ATTR_ADDR];
+	err = mptcp_pm_parse_entry(laddr, info, true, &entry);
+	if (err < 0)
+		goto create_err;
+
+	if (entry.flags & MPTCP_PM_ADDR_FLAG_SIGNAL) {
+		NL_SET_ERR_MSG_ATTR(info->extack, laddr, "invalid addr flags");
+		err = -EINVAL;
+		goto create_err;
+	}
+	entry.flags |= MPTCP_PM_ADDR_FLAG_SUBFLOW;
+
+	raddr = info->attrs[MPTCP_PM_ATTR_ADDR_REMOTE];
+	err = mptcp_pm_parse_addr(raddr, info, &addr_r);
+	if (err < 0)
+		goto create_err;
+
+	if (!mptcp_pm_addr_families_match(sk, &entry.addr, &addr_r)) {
+		GENL_SET_ERR_MSG(info, "families mismatch");
+		err = -EINVAL;
+		goto create_err;
+	}
+
+	err = mptcp_userspace_pm_append_new_local_addr(msk, &entry, false);
+	if (err < 0) {
+		NL_SET_ERR_MSG_ATTR(info->extack, laddr,
+				    "did not match address and id");
+		goto create_err;
+	}
+
+	local.addr = entry.addr;
+	local.flags = entry.flags;
+	local.ifindex = entry.ifindex;
+
+	spin_lock_bh(&msk->pm.lock);
+	msk->pm.extra_subflows++;
+	spin_unlock_bh(&msk->pm.lock);
+
+	lock_sock(sk);
+	err = __mptcp_subflow_connect(sk, &local, &addr_r);
+	release_sock(sk);
+
+	if (err) {
+		GENL_SET_ERR_MSG_FMT(info, "connect error: %d", err);
+
+		spin_lock_bh(&msk->pm.lock);
+		mptcp_userspace_pm_delete_local_addr(msk, &entry);
+		spin_unlock_bh(&msk->pm.lock);
+	}
+
+ create_err:
+	sock_put(sk);
+	return err;
+}
+
+static struct sock *mptcp_nl_find_ssk(struct mptcp_sock *msk,
+				      const struct mptcp_addr_info *local,
+				      const struct mptcp_addr_info *remote)
+{
+	struct mptcp_subflow_context *subflow;
+
+	if (local->family != remote->family)
+		return NULL;
+
+	mptcp_for_each_subflow(msk, subflow) {
+		const struct inet_sock *issk;
+		struct sock *ssk;
+
+		ssk = mptcp_subflow_tcp_sock(subflow);
+
+		if (local->family != ssk->sk_family)
+			continue;
+
+		issk = inet_sk(ssk);
+
+		switch (ssk->sk_family) {
+		case AF_INET:
+			if (issk->inet_saddr != local->addr.s_addr ||
+			    issk->inet_daddr != remote->addr.s_addr)
+				continue;
+			break;
+#if IS_ENABLED(CONFIG_MPTCP_IPV6)
+		case AF_INET6: {
+			if (!ipv6_addr_equal(&local->addr6, &issk->pinet6->saddr) ||
+			    !ipv6_addr_equal(&remote->addr6, &ssk->sk_v6_daddr))
+				continue;
+			break;
+		}
+#endif
+		default:
+			continue;
+		}
+
+		if (issk->inet_sport == local->port &&
+		    issk->inet_dport == remote->port)
+			return ssk;
+	}
+
+	return NULL;
+}
+
+int mptcp_pm_nl_subflow_destroy_doit(struct sk_buff *skb, struct genl_info *info)
+{
+	struct mptcp_pm_addr_entry addr_l;
+	struct mptcp_addr_info addr_r;
+	struct nlattr *raddr, *laddr;
+	struct mptcp_sock *msk;
+	struct sock *sk, *ssk;
+	int err = -EINVAL;
+
+	if (GENL_REQ_ATTR_CHECK(info, MPTCP_PM_ATTR_ADDR) ||
+	    GENL_REQ_ATTR_CHECK(info, MPTCP_PM_ATTR_ADDR_REMOTE))
+		return err;
+
+	msk = mptcp_userspace_pm_get_sock(info);
+	if (!msk)
+		return err;
+
+	sk = (struct sock *)msk;
+
+	laddr = info->attrs[MPTCP_PM_ATTR_ADDR];
+	err = mptcp_pm_parse_entry(laddr, info, true, &addr_l);
+	if (err < 0)
+		goto destroy_err;
+
+	raddr = info->attrs[MPTCP_PM_ATTR_ADDR_REMOTE];
+	err = mptcp_pm_parse_addr(raddr, info, &addr_r);
+	if (err < 0)
+		goto destroy_err;
+
+#if IS_ENABLED(CONFIG_MPTCP_IPV6)
+	if (addr_l.addr.family == AF_INET && ipv6_addr_v4mapped(&addr_r.addr6)) {
+		ipv6_addr_set_v4mapped(addr_l.addr.addr.s_addr, &addr_l.addr.addr6);
+		addr_l.addr.family = AF_INET6;
+	}
+	if (addr_r.family == AF_INET && ipv6_addr_v4mapped(&addr_l.addr.addr6)) {
+		ipv6_addr_set_v4mapped(addr_r.addr.s_addr, &addr_r.addr6);
+		addr_r.family = AF_INET6;
+	}
+#endif
+	if (addr_l.addr.family != addr_r.family) {
+		GENL_SET_ERR_MSG(info, "address families do not match");
+		err = -EINVAL;
+		goto destroy_err;
+	}
+
+	if (!addr_l.addr.port) {
+		NL_SET_ERR_MSG_ATTR(info->extack, laddr, "missing local port");
+		err = -EINVAL;
+		goto destroy_err;
+	}
+
+	if (!addr_r.port) {
+		NL_SET_ERR_MSG_ATTR(info->extack, raddr, "missing remote port");
+		err = -EINVAL;
+		goto destroy_err;
+	}
+
+	lock_sock(sk);
+	ssk = mptcp_nl_find_ssk(msk, &addr_l.addr, &addr_r);
+	if (!ssk) {
+		GENL_SET_ERR_MSG(info, "subflow not found");
+		err = -ESRCH;
+		goto release_sock;
+	}
+
+	spin_lock_bh(&msk->pm.lock);
+	mptcp_userspace_pm_delete_local_addr(msk, &addr_l);
+	spin_unlock_bh(&msk->pm.lock);
+	mptcp_subflow_shutdown(sk, ssk, RCV_SHUTDOWN | SEND_SHUTDOWN);
+	mptcp_close_ssk(sk, ssk, mptcp_subflow_ctx(ssk));
+	MPTCP_INC_STATS(sock_net(sk), MPTCP_MIB_RMSUBFLOW);
+release_sock:
+	release_sock(sk);
+
+destroy_err:
+	sock_put(sk);
+	return err;
+}
+
+int mptcp_userspace_pm_set_flags(struct mptcp_pm_addr_entry *local,
+				 struct genl_info *info)
+{
+	struct mptcp_addr_info rem = { .family = AF_UNSPEC, };
+	struct mptcp_pm_addr_entry *entry;
+	struct nlattr *attr, *attr_rem;
+	struct mptcp_sock *msk;
+	int ret = -EINVAL;
+	struct sock *sk;
+	u8 bkup = 0;
+
+	if (GENL_REQ_ATTR_CHECK(info, MPTCP_PM_ATTR_ADDR_REMOTE))
+		return ret;
+
+	msk = mptcp_userspace_pm_get_sock(info);
+	if (!msk)
+		return ret;
+
+	sk = (struct sock *)msk;
+
+	attr = info->attrs[MPTCP_PM_ATTR_ADDR];
+	if (local->addr.family == AF_UNSPEC) {
+		NL_SET_ERR_MSG_ATTR(info->extack, attr,
+				    "invalid local address family");
+		ret = -EINVAL;
+		goto set_flags_err;
+	}
+
+	attr_rem = info->attrs[MPTCP_PM_ATTR_ADDR_REMOTE];
+	ret = mptcp_pm_parse_addr(attr_rem, info, &rem);
+	if (ret < 0)
+		goto set_flags_err;
+
+	if (rem.family == AF_UNSPEC) {
+		NL_SET_ERR_MSG_ATTR(info->extack, attr_rem,
+				    "invalid remote address family");
+		ret = -EINVAL;
+		goto set_flags_err;
+	}
+
+	if (local->flags & MPTCP_PM_ADDR_FLAG_BACKUP)
+		bkup = 1;
+
+	spin_lock_bh(&msk->pm.lock);
+	entry = mptcp_userspace_pm_lookup_addr(msk, &local->addr);
+	if (entry) {
+		if (bkup)
+			entry->flags |= MPTCP_PM_ADDR_FLAG_BACKUP;
+		else
+			entry->flags &= ~MPTCP_PM_ADDR_FLAG_BACKUP;
+	}
+	spin_unlock_bh(&msk->pm.lock);
+
+	lock_sock(sk);
+	ret = mptcp_pm_mp_prio_send_ack(msk, &local->addr, &rem, bkup);
+	release_sock(sk);
+
+	/* mptcp_pm_mp_prio_send_ack() only fails in one case */
+	if (ret < 0)
+		GENL_SET_ERR_MSG(info, "subflow not found");
+
+set_flags_err:
+	sock_put(sk);
+	return ret;
+}
+
+int mptcp_userspace_pm_dump_addr(struct sk_buff *msg,
+				 struct netlink_callback *cb)
+{
+	struct id_bitmap {
+		DECLARE_BITMAP(map, MPTCP_PM_MAX_ADDR_ID + 1);
+	} *bitmap;
+	const struct genl_info *info = genl_info_dump(cb);
+	struct mptcp_pm_addr_entry *entry;
+	struct mptcp_sock *msk;
+	int ret = -EINVAL;
+	struct sock *sk;
+
+	BUILD_BUG_ON(sizeof(struct id_bitmap) > sizeof(cb->ctx));
+
+	bitmap = (struct id_bitmap *)cb->ctx;
+
+	msk = mptcp_userspace_pm_get_sock(info);
+	if (!msk)
+		return ret;
+
+	sk = (struct sock *)msk;
+
+	lock_sock(sk);
+	spin_lock_bh(&msk->pm.lock);
+	mptcp_for_each_userspace_pm_addr(msk, entry) {
+		if (test_bit(entry->addr.id, bitmap->map))
+			continue;
+
+		if (mptcp_pm_genl_fill_addr(msg, cb, entry) < 0)
+			break;
+
+		__set_bit(entry->addr.id, bitmap->map);
+	}
+	spin_unlock_bh(&msk->pm.lock);
+	release_sock(sk);
+	ret = msg->len;
+
+	sock_put(sk);
+	return ret;
+}
+
+int mptcp_userspace_pm_get_addr(u8 id, struct mptcp_pm_addr_entry *addr,
+				struct genl_info *info)
+{
+	struct mptcp_pm_addr_entry *entry;
+	struct mptcp_sock *msk;
+	int ret = -EINVAL;
+	struct sock *sk;
+
+	msk = mptcp_userspace_pm_get_sock(info);
+	if (!msk)
+		return ret;
+
+	sk = (struct sock *)msk;
+
+	lock_sock(sk);
+	spin_lock_bh(&msk->pm.lock);
+	entry = mptcp_userspace_pm_lookup_addr_by_id(msk, id);
+	if (entry) {
+		*addr = *entry;
+		ret = 0;
+	}
+	spin_unlock_bh(&msk->pm.lock);
+	release_sock(sk);
+
+	sock_put(sk);
+	return ret;
+}
+
+static struct mptcp_pm_ops mptcp_pm_userspace = {
+	.name			= "userspace",
+	.owner			= THIS_MODULE,
+};
+
+void __init mptcp_pm_userspace_register(void)
+{
+	mptcp_pm_register(&mptcp_pm_userspace);
+}