leds: trigger: Unregister sysfs attributes before calling deactivate()

Triggers which have trigger specific sysfs attributes typically store
related data in trigger-data allocated by the activate() callback and
freed by the deactivate() callback.

Calling device_remove_groups() after calling deactivate() leaves a window
where the sysfs attributes show/store functions could be called after
deactivation and then operate on the just freed trigger-data.

Move the device_remove_groups() call to before deactivate() to close
this race window.

This also makes the deactivation path properly do things in reverse order
of the activation path which calls the activate() callback before calling
device_add_groups().

Fixes: a7e7a3156300 ("leds: triggers: add device attribute support")
Cc: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
Signed-off-by: Hans de Goede <hdegoede@redhat.com>
Acked-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
Link: https://lore.kernel.org/r/20240504162533.76780-1-hdegoede@redhat.com
Signed-off-by: Lee Jones <lee@kernel.org>

diff --git a/drivers/leds/led-triggers.c b/drivers/leds/led-triggers.c
index 638aa6591092b89beb3923b8223c59d1d3657832..4d1a506a772c5e38fdc8b00c27901051b034461f 100644 (file)
--- a/drivers/leds/led-triggers.c
+++ b/drivers/leds/led-triggers.c
@@ -179,9 +179,9 @@ int led_trigger_set(struct led_classdev *led_cdev, struct led_trigger *trig)
 
                cancel_work_sync(&led_cdev->set_brightness_work);
                led_stop_software_blink(led_cdev);
+               device_remove_groups(led_cdev->dev, led_cdev->trigger->groups);
                if (led_cdev->trigger->deactivate)
                        led_cdev->trigger->deactivate(led_cdev);
-               device_remove_groups(led_cdev->dev, led_cdev->trigger->groups);
                led_cdev->trigger = NULL;
                led_cdev->trigger_data = NULL;
                led_cdev->activated = false;