From: Lorenzo Bianconi lorenzo@kernel.org

commit 41130c32f3a18fcc930316da17f3a5f3bc326aa1 upstream.

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 Signed-off-by: Georg Müller georgmueller@gmx.net Link: https://lore.kernel.org/r/be3457d82f4e44bb71a22b2b5db27b644a37b1e1.167710727... --- 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 6de13d641438..82fce4b1d581 100644 --- a/drivers/net/wireless/mediatek/mt76/mac80211.c +++ b/drivers/net/wireless/mediatek/mt76/mac80211.c @@ -522,6 +522,7 @@ 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; @@ -532,6 +533,9 @@ 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; @@ -654,6 +658,7 @@ 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; @@ -664,6 +669,9 @@ 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 60c9f9c56a4f..5b03e3b33d54 100644 --- a/drivers/net/wireless/mediatek/mt76/mt76.h +++ b/drivers/net/wireless/mediatek/mt76/mt76.h @@ -388,6 +388,7 @@ struct mt76_tx_cb {

enum { MT76_STATE_INITIALIZED, + MT76_STATE_REGISTERED, MT76_STATE_RUNNING, MT76_STATE_MCU_RUNNING, MT76_SCANNING, -- 2.46.2