In mptcp_pm_create_subflow_or_signal_addr(), rcu_read_(un)lock() are
used as expected to iterate over the list of local addresses, but
list_for_each_entry() was used instead of list_for_each_entry_rcu() in
__lookup_addr(). It is important to use this variant which adds the
required READ_ONCE() (and diagnostic checks if enabled).

Because __lookup_addr() is also used in mptcp_pm_nl_set_flags() where it
is called under the pernet->lock and not rcu_read_lock(), an extra
condition is then passed to help the diagnostic checks making sure
either the associated spin lock or the RCU lock is held.

Fixes: 86e39e04482b ("mptcp: keep track of local endpoint still available for each msk")
Signed-off-by: Matthieu Baerts (NGI0) <matttbe@kernel.org>
---
v3:
- Use list_for_each_entry_rcu() with lockdep_is_held().
- Update commit message accordingly.
---
 net/mptcp/pm_netlink.c | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/net/mptcp/pm_netlink.c b/net/mptcp/pm_netlink.c
index 618289aac0ab7f558d55d8b2ebb00dc62fc72f88..758a0dbfcf78e545d840c0b580c0b12bd042d7a4 100644
--- a/net/mptcp/pm_netlink.c
+++ b/net/mptcp/pm_netlink.c
@@ -524,7 +524,8 @@ __lookup_addr(struct pm_nl_pernet *pernet, const struct mptcp_addr_info *info)
 {
 	struct mptcp_pm_addr_entry *entry;
 
-	list_for_each_entry(entry, &pernet->local_addr_list, list) {
+	list_for_each_entry_rcu(entry, &pernet->local_addr_list, list,
+				lockdep_is_held(&pernet->lock)) {
 		if (mptcp_addresses_equal(&entry->addr, info, entry->addr.port))
 			return entry;
 	}

-- 
2.45.2