[PATCH] wifi: mt76: mt7615: restore DBDC state after ext PHY failure

[Myeonghun Pak]

mt7615_register_ext_phy() limits the primary PHY to DBDC capabilities
before allocating and registering the secondary PHY. If allocation,
EEPROM override, or PHY registration fails, it returns without restoring
the primary PHY capabilities. The EEPROM override failure also leaks the
newly allocated ieee80211_hw.

Route all failures through common labels that free the secondary hardware
when it was allocated and restore the primary PHY capabilities.

This issue was identified during our ongoing static-analysis research while
reviewing kernel code.

Fixes: 0f2173f093b3 ("mt76: mt7615: add support for registering a second wiphy via debugfs")
Cc: stable at vger.kernel.org
Co-developed-by: Ijae Kim <ae878000 at gmail.com>
Signed-off-by: Ijae Kim <ae878000 at gmail.com>
Signed-off-by: Myeonghun Pak <mhun512 at gmail.com>
---
 .../net/wireless/mediatek/mt76/mt7615/init.c    | 17 +++++++++++++----
 1 file changed, 13 insertions(+), 4 deletions(-)

diff --git a/drivers/net/wireless/mediatek/mt76/mt7615/init.c b/drivers/net/wireless/mediatek/mt76/mt7615/init.c
index 42e11ba1206ee..02e51b2d42ed8 100644
--- a/drivers/net/wireless/mediatek/mt76/mt7615/init.c
+++ b/drivers/net/wireless/mediatek/mt76/mt7615/init.c
@@ -542,8 +542,10 @@ int mt7615_register_ext_phy(struct mt7615_dev *dev)
 
 	mt7615_cap_dbdc_enable(dev);
 	mphy = mt76_alloc_phy(&dev->mt76, sizeof(*phy), &mt7615_ops, MT_BAND1);
-	if (!mphy)
-		return -ENOMEM;
+	if (!mphy) {
+		ret = -ENOMEM;
+		goto error;
+	}
 
 	phy = mphy->priv;
 	phy->dev = dev;
@@ -573,7 +575,7 @@ int mt7615_register_ext_phy(struct mt7615_dev *dev)
 
 	ret = mt76_eeprom_override(mphy);
 	if (ret)
-		return ret;
+		goto error_free_hw;
 
 	/* second phy can only handle 5 GHz */
 	mphy->cap.has_5ghz = true;
@@ -591,7 +593,14 @@ int mt7615_register_ext_phy(struct mt7615_dev *dev)
 	ret = mt76_register_phy(mphy, true, mt76_rates,
 				ARRAY_SIZE(mt76_rates));
 	if (ret)
-		ieee80211_free_hw(mphy->hw);
+		goto error_free_hw;
+
+	return 0;
+
+error_free_hw:
+	ieee80211_free_hw(mphy->hw);
+error:
+	mt7615_cap_dbdc_disable(dev);
 
 	return ret;
 }
-- 
2.47.1