Merge branch 'mptcp-a-few-fixes'

Mat Martineau says:

====================
mptcp: A few fixes

Patch 1 fixes a RCU locking issue when processing a netlink command that
updates endpoint flags in the in-kernel MPTCP path manager.

Patch 2 fixes a typo affecting available endpoint id tracking.

Patch 3 fixes IPv6 routing in the MPTCP self tests.
====================

Link: https://lore.kernel.org/r/20220121003529.54930-1-mathew.j.martineau@linux.intel.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

net/mptcp/pm_netlink.c

@@ -478,6 +478,20 @@ __lookup_addr_by_id(struct pm_nl_pernet *pernet, unsigned int id)
 	return NULL;
 }
 
+static struct mptcp_pm_addr_entry *
+__lookup_addr(struct pm_nl_pernet *pernet, const struct mptcp_addr_info *info,
+	      bool lookup_by_id)
+{
+	struct mptcp_pm_addr_entry *entry;
+
+	list_for_each_entry(entry, &pernet->local_addr_list, list) {
+		if ((!lookup_by_id && addresses_equal(&entry->addr, info, true)) ||
+		    (lookup_by_id && entry->addr.id == info->id))
+			return entry;
+	}
+	return NULL;
+}
+
 static int
 lookup_id_by_addr(struct pm_nl_pernet *pernet, const struct mptcp_addr_info *addr)
 {
@@ -777,7 +791,7 @@ static void mptcp_pm_nl_rm_addr_or_subflow(struct mptcp_sock *msk,
 			removed = true;
 			__MPTCP_INC_STATS(sock_net(sk), rm_type);
 		}
-		__set_bit(rm_list->ids[1], msk->pm.id_avail_bitmap);
+		__set_bit(rm_list->ids[i], msk->pm.id_avail_bitmap);
 		if (!removed)
 			continue;
 
@@ -1763,18 +1777,21 @@ static int mptcp_nl_cmd_set_flags(struct sk_buff *skb, struct genl_info *info)
 			return -EOPNOTSUPP;
 	}
 
-	list_for_each_entry(entry, &pernet->local_addr_list, list) {
-		if ((!lookup_by_id && addresses_equal(&entry->addr, &addr.addr, true)) ||
-		    (lookup_by_id && entry->addr.id == addr.addr.id)) {
-			mptcp_nl_addr_backup(net, &entry->addr, bkup);
-
-			if (bkup)
-				entry->flags |= MPTCP_PM_ADDR_FLAG_BACKUP;
-			else
-				entry->flags &= ~MPTCP_PM_ADDR_FLAG_BACKUP;
-		}
+	spin_lock_bh(&pernet->lock);
+	entry = __lookup_addr(pernet, &addr.addr, lookup_by_id);
+	if (!entry) {
+		spin_unlock_bh(&pernet->lock);
+		return -EINVAL;
 	}
 
+	if (bkup)
+		entry->flags |= MPTCP_PM_ADDR_FLAG_BACKUP;
+	else
+		entry->flags &= ~MPTCP_PM_ADDR_FLAG_BACKUP;
+	addr = *entry;
+	spin_unlock_bh(&pernet->lock);
+
+	mptcp_nl_addr_backup(net, &addr.addr, bkup);
 	return 0;
 }
 

tools/testing/selftests/net/mptcp/mptcp_join.sh

@@ -75,6 +75,7 @@ init()
 
 		# let $ns2 reach any $ns1 address from any interface
 		ip -net "$ns2" route add default via 10.0.$i.1 dev ns2eth$i metric 10$i
+		ip -net "$ns2" route add default via dead:beef:$i::1 dev ns2eth$i metric 10$i
 	done
 }
 
@@ -1476,7 +1477,7 @@ ipv6_tests()
 	reset
 	ip netns exec $ns1 ./pm_nl_ctl limits 0 1
 	ip netns exec $ns2 ./pm_nl_ctl limits 0 1
-	ip netns exec $ns2 ./pm_nl_ctl add dead:beef:3::2 flags subflow
+	ip netns exec $ns2 ./pm_nl_ctl add dead:beef:3::2 dev ns2eth3 flags subflow
 	run_tests $ns1 $ns2 dead:beef:1::1 0 0 0 slow
 	chk_join_nr "single subflow IPv6" 1 1 1
 
@@ -1511,7 +1512,7 @@ ipv6_tests()
 	ip netns exec $ns1 ./pm_nl_ctl limits 0 2
 	ip netns exec $ns1 ./pm_nl_ctl add dead:beef:2::1 flags signal
 	ip netns exec $ns2 ./pm_nl_ctl limits 1 2
-	ip netns exec $ns2 ./pm_nl_ctl add dead:beef:3::2 flags subflow
+	ip netns exec $ns2 ./pm_nl_ctl add dead:beef:3::2 dev ns2eth3 flags subflow
 	run_tests $ns1 $ns2 dead:beef:1::1 0 -1 -1 slow
 	chk_join_nr "remove subflow and signal IPv6" 2 2 2
 	chk_add_nr 1 1