wifi: mt76: mt7925: publish msta->link after successful link add

Move the msta->link[link_id] publication until after
mt7925_mac_link_sta_add() succeeds.

msta->link[] is RCU-visible, so publishing it before setup completes can
expose a link whose add path later fails. Publish it only after success
to avoid partially initialized link state becoming visible.

Signed-off-by: Sean Wang <sean.wang@mediatek.com>
Link: https://patch.msgid.link/20260306232238.2039675-19-sean.wang@kernel.org
Signed-off-by: Felix Fietkau <nbd@nbd.name>

diff --git a/drivers/net/wireless/mediatek/mt76/mt7925/main.c b/drivers/net/wireless/mediatek/mt76/mt7925/main.c
index eb16c4683100fc2d340505e8db7b939c1f34901a..95c631b57894d38c17e493480aedbec747a6a7a1 100644 (file)
--- a/drivers/net/wireless/mediatek/mt76/mt7925/main.c
+++ b/drivers/net/wireless/mediatek/mt76/mt7925/main.c
@@ -1000,10 +1000,11 @@ mt7925_mac_sta_add_links(struct mt792x_dev *dev, struct ieee80211_vif *vif,
        for_each_set_bit(link_id, &new_links, IEEE80211_MLD_MAX_NUM_LINKS) {
                struct ieee80211_link_sta *link_sta;
                struct mt792x_link_sta *mlink;
+               bool is_deflink = false;
 
                if (msta->deflink_id == IEEE80211_LINK_UNSPECIFIED) {
                        mlink = &msta->deflink;
-                       msta->deflink_id = link_id;
+                       is_deflink = true;
                } else {
                        mlink = kzalloc(sizeof(*mlink), GFP_KERNEL);
                        if (!mlink) {
@@ -1012,14 +1013,23 @@ mt7925_mac_sta_add_links(struct mt792x_dev *dev, struct ieee80211_vif *vif,
                        }
                }
 
-               msta->valid_links |= BIT(link_id);
-               rcu_assign_pointer(msta->link[link_id], mlink);
                mlink->sta = msta;
                mlink->pri_link = &sta->deflink;
                mlink->wcid.def_wcid = &msta->deflink.wcid;
 
                link_sta = mt792x_sta_to_link_sta(vif, sta, link_id);
-               mt7925_mac_link_sta_add(&dev->mt76, vif, link_sta, mlink);
+               err = mt7925_mac_link_sta_add(&dev->mt76, vif, link_sta, mlink);
+               if (err) {
+                       if (!is_deflink)
+                               kfree_rcu(mlink, rcu_head);
+                       break;
+               }
+
+               if (is_deflink)
+                       msta->deflink_id = link_id;
+
+               rcu_assign_pointer(msta->link[link_id], mlink);
+               msta->valid_links |= BIT(link_id);
        }
 
        return err;