[PATCH] mt76: do not use devm API for led classdev
From: Felix Fietkau <nbd@nbd.name>
Date: 2019-09-29 20:11:45
Subsystem:
mediatek mt76 wireless lan driver, the rest · Maintainers:
Felix Fietkau, Lorenzo Bianconi, Ryder Lee, Linus Torvalds
With the devm API, the unregister happens after the device cleanup is done, after which the struct mt76_dev which contains the led_cdev has already been freed. This leads to a use-after-free bug that can crash the system. Signed-off-by: Felix Fietkau <nbd@nbd.name> --- drivers/net/wireless/mediatek/mt76/mac80211.c | 11 ++++++++++- 1 file changed, 10 insertions(+), 1 deletion(-)
diff --git a/drivers/net/wireless/mediatek/mt76/mac80211.c b/drivers/net/wireless/mediatek/mt76/mac80211.c
index 9a59a1b54c97..a962abce98f8 100644
--- a/drivers/net/wireless/mediatek/mt76/mac80211.c
+++ b/drivers/net/wireless/mediatek/mt76/mac80211.c@@ -105,7 +105,15 @@ static int mt76_led_init(struct mt76_dev *dev) dev->led_al = of_property_read_bool(np, "led-active-low"); } - return devm_led_classdev_register(dev->dev, &dev->led_cdev); + return led_classdev_register(dev->dev, &dev->led_cdev); +} + +static void mt76_led_cleanup(struct mt76_dev *dev) +{ + if (!dev->led_cdev.brightness_set && !dev->led_cdev.blink_set) + return; + + led_classdev_unregister(&dev->led_cdev); } static void mt76_init_stream_cap(struct mt76_dev *dev,
@@ -362,6 +370,7 @@ void mt76_unregister_device(struct mt76_dev *dev) { struct ieee80211_hw *hw = dev->hw; + mt76_led_cleanup(dev); mt76_tx_status_check(dev, NULL, true); ieee80211_unregister_hw(hw); }
--
2.17.0