wifi: mac80211: finish link init before RCU publish

Since the link/conf pointers can be accessed without any
protection other than RCU, make sure the data is actually
set up before publishing the structures.

Fixes: b2e8434f1829 ("wifi: mac80211: set up/tear down client vif links properly")
Link: https://patch.msgid.link/20250624130749.9a308b713c74.I4a80f5eead112a38730939ea591d2e275c721256@changeid
Signed-off-by: Johannes Berg <johannes.berg@intel.com>

diff --git a/net/mac80211/link.c b/net/mac80211/link.c
index d40c2bd3b50b086e2ef3646b448c77b1172a150b..4f7b7d0f64f24b760026bb55c16119ea2c9066d1 100644 (file)
--- a/net/mac80211/link.c
+++ b/net/mac80211/link.c
@@ -93,9 +93,6 @@ void ieee80211_link_init(struct ieee80211_sub_if_data *sdata,
        if (link_id < 0)
                link_id = 0;
 
-       rcu_assign_pointer(sdata->vif.link_conf[link_id], link_conf);
-       rcu_assign_pointer(sdata->link[link_id], link);
-
        if (sdata->vif.type == NL80211_IFTYPE_AP_VLAN) {
                struct ieee80211_sub_if_data *ap_bss;
                struct ieee80211_bss_conf *ap_bss_conf;
@@ -145,6 +142,9 @@ void ieee80211_link_init(struct ieee80211_sub_if_data *sdata,
 
                ieee80211_link_debugfs_add(link);
        }
+
+       rcu_assign_pointer(sdata->vif.link_conf[link_id], link_conf);
+       rcu_assign_pointer(sdata->link[link_id], link);
 }
 
 void ieee80211_link_stop(struct ieee80211_link_data *link)