Re: [PATCH] wifi: mt76: add missing lock protection in mt76_sta_state for sta_event callback
From: Sean Wang <sean.wang@kernel.org>
Date: 2026-01-31 01:37:11
Also in:
linux-mediatek, linux-wireless, lkml
On Thu, Jan 29, 2026 at 9:25 PM Ziyi Guo [off-list ref] wrote:
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.
The mt7921 / mt7925 .sta_event callback already holds the lock; this patch would cause a deadlock. Suggest adding the implementation to MT7915.
quoted hunk ↗ jump to hunk
Signed-off-by: Ziyi Guo <redacted> --- 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