[PATCH] wifi: mt76: add missing lock protection in mt76_sta_state for sta_event callback

[Ziyi Guo]

mt76_sta_state() calls the sta_event callback without holding dev->mutex.
However, mt7915_mac_sta_event() (MT7915 implementation of this callback)
calls mt7915_mac_twt_teardown_flow() which has 
lockdep_assert_held(&dev->mt76.mutex) indicating that callers must 
hold this lock.

The locking pattern in mt76_sta_state() is inconsistent:
- mt76_sta_add() acquires dev->mutex before calling dev->drv->sta_add
- mt76_sta_remove() acquires dev->mutex before calling __mt76_sta_remove
- But sta_event callback is called without acquiring the lock

Add mutex_lock()/mutex_unlock() around the sta_event callback invocation
to fix the missing lock protection and maintain consistency with the
existing locking pattern.

Signed-off-by: Ziyi Guo <n7l8m4 at u.northwestern.edu>
---
 drivers/net/wireless/mediatek/mt76/mac80211.c | 7 ++++++-
 1 file changed, 6 insertions(+), 1 deletion(-)

diff --git a/drivers/net/wireless/mediatek/mt76/mac80211.c b/drivers/net/wireless/mediatek/mt76/mac80211.c
index 75772979f438..468bc176bacb 100644
--- a/drivers/net/wireless/mediatek/mt76/mac80211.c
+++ b/drivers/net/wireless/mediatek/mt76/mac80211.c
@@ -1640,6 +1640,7 @@ int mt76_sta_state(struct ieee80211_hw *hw, struct ieee80211_vif *vif,
 	struct mt76_phy *phy = hw->priv;
 	struct mt76_dev *dev = phy->dev;
 	enum mt76_sta_event ev;
+	int ret;
 
 	phy = mt76_vif_phy(hw, vif);
 	if (!phy)
@@ -1668,7 +1669,11 @@ int mt76_sta_state(struct ieee80211_hw *hw, struct ieee80211_vif *vif,
 	else
 		return 0;
 
-	return dev->drv->sta_event(dev, vif, sta, ev);
+	mutex_lock(&dev->mutex);
+	ret = dev->drv->sta_event(dev, vif, sta, ev);
+	mutex_unlock(&dev->mutex);
+
+	return ret;
 }
 EXPORT_SYMBOL_GPL(mt76_sta_state);
 
-- 
2.34.1