[PATCH v2 4/5] HID: dualshock4_remove: manually unregister leds

[Pietro Borrello]

Unregister the LED controllers before device removal, to prevent
unnecessary runs of dualshock4_led_set_brightness().

Fixes: 4521109a8f40 ("HID: playstation: support DualShock4 lightbar.")
Signed-off-by: Pietro Borrello <borrello@xxxxxxxxxxxxxxxx>

---

Contrary to the other patches in this series, failing to unregister
the led controller does not results into a use-after-free thanks
to the output_worker_initialized variable and the spinlock checks.

Changes in v2:
- Clarify UAF
- Link to v1: https://lore.kernel.org/all/20230125-hid-unregister-leds-v1-4-9a5192dcef16@xxxxxxxxxxxxxxxx/
---
 drivers/hid/hid-playstation.c | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/drivers/hid/hid-playstation.c b/drivers/hid/hid-playstation.c
index f23186ca2d76..b41657842e26 100644
--- a/drivers/hid/hid-playstation.c
+++ b/drivers/hid/hid-playstation.c
@@ -2434,11 +2434,15 @@ static void dualshock4_remove(struct ps_device *ps_dev)
 {
 	struct dualshock4 *ds4 = container_of(ps_dev, struct dualshock4, base);
 	unsigned long flags;
+	int i;
 
 	spin_lock_irqsave(&ds4->base.lock, flags);
 	ds4->output_worker_initialized = false;
 	spin_unlock_irqrestore(&ds4->base.lock, flags);
 
+	for (i = 0; i < ARRAY_SIZE(ds4->lightbar_leds); i++)
+		devm_led_classdev_unregister(&ps_dev->hdev->dev, &ds4->lightbar_leds[i]);
+
 	cancel_work_sync(&ds4->output_worker);
 
 	if (ps_dev->hdev->product == USB_DEVICE_ID_SONY_PS4_CONTROLLER_DONGLE)

-- 
2.25.1