FAILED: patch "[PATCH] wifi: mt76: mt7615: restore DBDC state after ext PHY failure" failed to apply to 6.6-stable tree

[Sasha Levin <sashal@kernel.org>]

The patch below does not apply to the 6.6-stable tree.
If someone wants it applied there, or to any other stable or longterm
tree, then please email the backport, including the original git commit
id to <stable@vger.kernel.org>.

To reproduce the conflict and resubmit, you may use the following commands:

git fetch https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/ linux-6.6.y
git checkout FETCH_HEAD
git cherry-pick -x 7907d5270dc5c13b6a95754c08a77d5b06bbc786
# <resolve conflicts, build, test, etc.>
git commit -s
git send-email --to '<stable@vger.kernel.org>' --in-reply-to '20261107053229-failed-6.6-7907d5270dc5@kernel.org' --subject-prefix 'PATCH 6.6.y' 'HEAD^..'

Thanks,
Sasha

------------------ original commit in Linus's tree ------------------

From 7907d5270dc5c13b6a95754c08a77d5b06bbc786 Mon Sep 17 00:00:00 2001
From: Myeonghun Pak <mhun512@gmail.com>
Date: Thu, 10 Sep 2026 17:54:41 -0400
Subject: [PATCH] wifi: mt76: mt7615: restore DBDC state after ext PHY failure

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@vger.kernel.org
Co-developed-by: Ijae Kim <ae878000@gmail.com>
Signed-off-by: Ijae Kim <ae878000@gmail.com>
Signed-off-by: Myeonghun Pak <mhun512@gmail.com>
Link: https://patch.msgid.link/20260910215441.76683-1-mhun512@gmail.com
Signed-off-by: Felix Fietkau <nbd@nbd.name>
---
 .../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 e437e088b2e91..665b0f1e939f1 100644
--- a/drivers/net/wireless/mediatek/mt76/mt7615/init.c
+++ b/drivers/net/wireless/mediatek/mt76/mt7615/init.c
@@ -541,8 +541,10 @@ 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;
@@ -572,7 +574,7 @@ 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;
@@ -590,7 +592,14 @@ 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;
 }
-- 
2.53.0