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From:   Greg Kroah-Hartman <gregkh@linuxfoundation.org>
To:     linux-kernel@vger.kernel.org
Cc:     Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
        stable@vger.kernel.org, Lorenzo Bianconi <lorenzo@kernel.org>,
        Felix Fietkau <nbd@nbd.name>, Sasha Levin <sashal@kernel.org>
Subject: [PATCH 5.9 319/757] mt76: mt7615: fix a possible NULL pointer dereference in mt7615_pm_wake_work
Date:   Tue, 27 Oct 2020 14:49:29 +0100
Message-Id: <20201027135505.500460671@linuxfoundation.org>
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From: Lorenzo Bianconi <lorenzo@kernel.org>

[ Upstream commit a081de174d11b12db9a94eb748041c2732f14c10 ]

Initialize wcid to global_wcid if msta is NULL in mt7615_pm_wake_work
routine since wcid will be dereferenced running mt76_tx()

Fixes: 2b8cdfb28d340 ("mt76: mt7615: wake device before pushing frames in mt7615_tx")
Signed-off-by: Lorenzo Bianconi <lorenzo@kernel.org>
Signed-off-by: Felix Fietkau <nbd@nbd.name>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
 drivers/net/wireless/mediatek/mt76/mt7615/mac.c | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/drivers/net/wireless/mediatek/mt76/mt7615/mac.c b/drivers/net/wireless/mediatek/mt76/mt7615/mac.c
index 3dd8dd28690ed..2be127018df6a 100644
--- a/drivers/net/wireless/mediatek/mt76/mt7615/mac.c
+++ b/drivers/net/wireless/mediatek/mt76/mt7615/mac.c
@@ -1853,12 +1853,13 @@ void mt7615_pm_wake_work(struct work_struct *work)
 	spin_lock_bh(&dev->pm.txq_lock);
 	for (i = 0; i < IEEE80211_NUM_ACS; i++) {
 		struct mt7615_sta *msta = dev->pm.tx_q[i].msta;
-		struct mt76_wcid *wcid = msta ? &msta->wcid : NULL;
 		struct ieee80211_sta *sta = NULL;
+		struct mt76_wcid *wcid;
 
 		if (!dev->pm.tx_q[i].skb)
 			continue;
 
+		wcid = msta ? &msta->wcid : &dev->mt76.global_wcid;
 		if (msta && wcid->sta)
 			sta = container_of((void *)msta, struct ieee80211_sta,
 					   drv_priv);
-- 
2.25.1