[PATCH v2 3/5] HID: dualsense_remove: manually unregister leds

[Pietro Borrello]

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

Fixes: 8c0ab553b072 ("HID: playstation: expose DualSense player LEDs through LED class.")
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:
- Unregister multicolor led controller
- Clarify UAF
- Link to v1: https://lore.kernel.org/all/20230125-hid-unregister-leds-v1-3-9a5192dcef16@xxxxxxxxxxxxxxxx/
---
 drivers/hid/hid-playstation.c | 6 ++++++
 1 file changed, 6 insertions(+)

diff --git a/drivers/hid/hid-playstation.c b/drivers/hid/hid-playstation.c
index 27c40894acab..f23186ca2d76 100644
--- a/drivers/hid/hid-playstation.c
+++ b/drivers/hid/hid-playstation.c
@@ -1503,11 +1503,17 @@ static void dualsense_remove(struct ps_device *ps_dev)
 {
 	struct dualsense *ds = container_of(ps_dev, struct dualsense, base);
 	unsigned long flags;
+	int i;
 
 	spin_lock_irqsave(&ds->base.lock, flags);
 	ds->output_worker_initialized = false;
 	spin_unlock_irqrestore(&ds->base.lock, flags);
 
+	for (i = 0; i < ARRAY_SIZE(ds->player_leds); i++)
+		devm_led_classdev_unregister(&ps_dev->hdev->dev, &ds->player_leds[i]);
+
+	devm_led_classdev_multicolor_unregister(&ps_dev->hdev->dev, &ds->lightbar);
+
 	cancel_work_sync(&ds->output_worker);
 }
 

-- 
2.25.1