wifi: mt76: Fix memory leak after mt76_connac_mcu_alloc_sta_req()

mainline inclusion
from mainline-v7.1-rc1
category: bugfix

mt76_connac_mcu_alloc_sta_req() allocates an skb which is expected to
be freed eventually by mt76_mcu_skb_send_msg(). However, currently if
an intermediate function fails before sending, the allocated skb is
leaked.

Specifically, mt76_connac_mcu_sta_wed_update() and
mt76_connac_mcu_sta_key_tlv() may fail, leading to an immediate memory
leak in the error path.

Fix this by explicitly freeing the skb in these error paths.
Commit 7c0f63f ("wifi: mt76: mt7996: fix memory leak on
mt7996_mcu_sta_key_tlv error") made a similar change.

Compile tested only. Issue found using a prototype static analysis tool
and code review.

Fixes: d1369e5 ("wifi: mt76: connac: introduce mt76_connac_mcu_sta_wed_update utility routine")
Fixes: 6683d98 ("mt76: connac: move mt76_connac_mcu_add_key in connac module")
Fixes: 4f831d1 ("wifi: mt76: mt7915: enable WED RX support")
Fixes: c948b5d ("wifi: mt76: mt7925: add Mediatek Wi-Fi7 driver for mt7925 chips")
Signed-off-by: Zilin Guan <zilin@seu.edu.cn>
Link: https://patch.msgid.link/20260116144919.1482558-1-zilin@seu.edu.cn
Signed-off-by: Felix Fietkau <nbd@nbd.name>
(cherry picked from commit c41075ce8cf05ed8c0e7b7efef000dce548ffc42)
Signed-off-by: Wentao Guan <guanwentao@uniontech.com>

Author: GoodLuck612

drivers/net/wireless/mediatek/mt76/mt76_connac_mcu.c

@@ -1283,8 +1283,10 @@ int mt76_connac_mcu_sta_ba(struct mt76_dev *dev, struct mt76_vif *mvif,
 				    wtbl_hdr);
 
 	ret = mt76_connac_mcu_sta_wed_update(dev, skb);
-	if (ret)
+	if (ret) {
+		dev_kfree_skb(skb);
 		return ret;
+	}
 
 	ret = mt76_mcu_skb_send_msg(dev, skb, cmd, true);
 	if (ret)
@@ -1297,8 +1299,10 @@ int mt76_connac_mcu_sta_ba(struct mt76_dev *dev, struct mt76_vif *mvif,
 	mt76_connac_mcu_sta_ba_tlv(skb, params, enable, tx);
 
 	ret = mt76_connac_mcu_sta_wed_update(dev, skb);
-	if (ret)
+	if (ret) {
+		dev_kfree_skb(skb);
 		return ret;
+	}
 
 	return mt76_mcu_skb_send_msg(dev, skb, cmd, true);
 }
@@ -2689,12 +2693,16 @@ int mt76_connac_mcu_add_key(struct mt76_dev *dev, struct ieee80211_vif *vif,
 		return PTR_ERR(skb);
 
 	ret = mt76_connac_mcu_sta_key_tlv(sta_key_conf, skb, key, cmd);
-	if (ret)
+	if (ret) {
+		dev_kfree_skb(skb);
 		return ret;
+	}
 
 	ret = mt76_connac_mcu_sta_wed_update(dev, skb);
-	if (ret)
+	if (ret) {
+		dev_kfree_skb(skb);
 		return ret;
+	}
 
 	return mt76_mcu_skb_send_msg(dev, skb, mcu_cmd, true);
 }

drivers/net/wireless/mediatek/mt76/mt7915/mcu.c

@@ -1715,8 +1715,10 @@ int mt7915_mcu_add_sta(struct mt7915_dev *dev, struct ieee80211_vif *vif,
 	}
 out:
 	ret = mt76_connac_mcu_sta_wed_update(&dev->mt76, skb);
-	if (ret)
+	if (ret) {
+		dev_kfree_skb(skb);
 		return ret;
+	}
 
 	return mt76_mcu_skb_send_msg(&dev->mt76, skb,
 				     MCU_EXT_CMD(STA_REC_UPDATE), true);

drivers/net/wireless/mediatek/mt76/mt7925/mcu.c

@@ -1116,8 +1116,10 @@ int mt7925_mcu_add_key(struct mt76_dev *dev, struct ieee80211_vif *vif,
 		return PTR_ERR(skb);
 
 	ret = mt7925_mcu_sta_key_tlv(wcid, sta_key_conf, skb, key, cmd, msta);
-	if (ret)
+	if (ret) {
+		dev_kfree_skb(skb);
 		return ret;
+	}
 
 	return mt76_mcu_skb_send_msg(dev, skb, mcu_cmd, true);
 }