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leds: triggers: Flush pending brightness before activating trigger

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The race fixed in timer_trig_activate() between a blocking
set_brightness() call and trigger->activate() can affect any trigger.
So move the call to flush_work() into led_trigger_set() where it can
avoid the race for all triggers.

Fixes: 0db37915d9 ("leds: avoid races with workqueue")
Fixes: 8c0f693c6e ("leds: avoid flush_work in atomic context")
Cc: stable@vger.kernel.org
Tested-by: Dustin L. Howett <dustin@howett.net>
Signed-off-by: Thomas Weißschuh <linux@weissschuh.net>
Link: https://lore.kernel.org/r/20240613-led-trigger-flush-v2-1-f4f970799d77@weissschuh.net
Signed-off-by: Lee Jones <lee@kernel.org>
This commit is contained in:
Thomas Weißschuh 2024-06-13 17:24:51 +02:00 committed by Lee Jones
parent 25458b2a40
commit ab477b766e
2 changed files with 6 additions and 5 deletions
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6
drivers/leds/led-triggers.c
View file

@ -201,6 +201,12 @@ int led_trigger_set(struct led_classdev *led_cdev, struct led_trigger *trig)
*/
synchronize_rcu();
/*
* If "set brightness to 0" is pending in workqueue,
* we don't want that to be reordered after ->activate()
*/
flush_work(&led_cdev->set_brightness_work);
ret = 0;
if (trig->activate)
ret = trig->activate(led_cdev);

5
drivers/leds/trigger/ledtrig-timer.c
View file

@ -110,11 +110,6 @@ static int timer_trig_activate(struct led_classdev *led_cdev)
led_cdev->flags &= ~LED_INIT_DEFAULT_TRIGGER;
}
/*
* If "set brightness to 0" is pending in workqueue, we don't
* want that to be reordered after blink_set()
*/
flush_work(&led_cdev->set_brightness_work);
led_blink_set(led_cdev, &led_cdev->blink_delay_on,
&led_cdev->blink_delay_off);