From: Lorenzo Bianconi <lorenzo@kernel.org>
Date: Thu, 23 Feb 2023 00:10:25 +0100
Subject: [PATCH] wifi: mt76: do not run mt76_unregister_device() on
 unregistered hw
References: bsc#1012628
Patch-mainline: 6.2.9
Git-commit: 41130c32f3a18fcc930316da17f3a5f3bc326aa1

[ Upstream commit 41130c32f3a18fcc930316da17f3a5f3bc326aa1 ]

Trying to probe a mt7921e pci card without firmware results in a
successful probe where ieee80211_register_hw hasn't been called. When
removing the driver, ieee802111_unregister_hw is called unconditionally
leading to a kernel NULL pointer dereference.
Fix the issue running mt76_unregister_device routine just for registered
hw.

Link: https://bugs.debian.org/1029116
Link: https://bugs.kali.org/view.php?id=8140
Reported-by: Stuart Hayhurst <stuart.a.hayhurst@gmail.com>
Fixes: 1c71e03afe4b ("mt76: mt7921: move mt7921_init_hw in a dedicated work")
Tested-by: Helmut Grohne <helmut@freexian.com>
Signed-off-by: Lorenzo Bianconi <lorenzo@kernel.org>
Signed-off-by: Kalle Valo <kvalo@kernel.org>
Link: https://lore.kernel.org/r/be3457d82f4e44bb71a22b2b5db27b644a37b1e1.1677107277.git.lorenzo@kernel.org
Signed-off-by: Sasha Levin <sashal@kernel.org>
Signed-off-by: Jiri Slaby <jslaby@suse.cz>
---
 drivers/net/wireless/mediatek/mt76/mac80211.c | 8 ++++++++
 drivers/net/wireless/mediatek/mt76/mt76.h     | 1 +
 2 files changed, 9 insertions(+)

diff --git a/drivers/net/wireless/mediatek/mt76/mac80211.c b/drivers/net/wireless/mediatek/mt76/mac80211.c
index fc608b36..d75e999a 100644
--- a/drivers/net/wireless/mediatek/mt76/mac80211.c
+++ b/drivers/net/wireless/mediatek/mt76/mac80211.c
@@ -526,6 +526,7 @@ int mt76_register_phy(struct mt76_phy *phy, bool vht,
 	if (ret)
 		return ret;
 
+	set_bit(MT76_STATE_REGISTERED, &phy->state);
 	phy->dev->phys[phy->band_idx] = phy;
 
 	return 0;
@@ -536,6 +537,9 @@ void mt76_unregister_phy(struct mt76_phy *phy)
 {
 	struct mt76_dev *dev = phy->dev;
 
+	if (!test_bit(MT76_STATE_REGISTERED, &phy->state))
+		return;
+
 	mt76_tx_status_check(dev, true);
 	ieee80211_unregister_hw(phy->hw);
 	dev->phys[phy->band_idx] = NULL;
@@ -663,6 +667,7 @@ int mt76_register_device(struct mt76_dev *dev, bool vht,
 		return ret;
 
 	WARN_ON(mt76_worker_setup(hw, &dev->tx_worker, NULL, "tx"));
+	set_bit(MT76_STATE_REGISTERED, &phy->state);
 	sched_set_fifo_low(dev->tx_worker.task);
 
 	return 0;
@@ -673,6 +678,9 @@ void mt76_unregister_device(struct mt76_dev *dev)
 {
 	struct ieee80211_hw *hw = dev->hw;
 
+	if (!test_bit(MT76_STATE_REGISTERED, &dev->phy.state))
+		return;
+
 	if (IS_ENABLED(CONFIG_MT76_LEDS))
 		mt76_led_cleanup(dev);
 	mt76_tx_status_check(dev, true);
diff --git a/drivers/net/wireless/mediatek/mt76/mt76.h b/drivers/net/wireless/mediatek/mt76/mt76.h
index 32a77a0a..d8216243 100644
--- a/drivers/net/wireless/mediatek/mt76/mt76.h
+++ b/drivers/net/wireless/mediatek/mt76/mt76.h
@@ -399,6 +399,7 @@ struct mt76_tx_cb {
 
 enum {
 	MT76_STATE_INITIALIZED,
+	MT76_STATE_REGISTERED,
 	MT76_STATE_RUNNING,
 	MT76_STATE_MCU_RUNNING,
 	MT76_SCANNING,
-- 
2.35.3