From f92135f100669b508dd62b424ab20bcb33494c79 Mon Sep 17 00:00:00 2001 From: Craig McQueen Date: Thu, 23 Apr 2026 21:36:38 +1000 Subject: [PATCH] leds: core: Fix race condition for software blink led_set_brightness() function: Change handling of software blink to avoid race conditions when stopping blink and setting brightness. Triggers may call led_set_brightness(LED_OFF), led_set_brightness(LED_FULL) in quick succession to disable blinking and turn the LED on. If the delayed work task has not yet disabled blinking by the time the second call occurs, then the brightness also needs to be changed in the delayed work task. Signed-off-by: Craig McQueen Link: https://patch.msgid.link/20260423113638.2079302-1-craig@mcqueen.au Signed-off-by: Lee Jones --- drivers/leds/led-core.c | 33 ++++++++++++++++++++------------- 1 file changed, 20 insertions(+), 13 deletions(-) diff --git a/drivers/leds/led-core.c b/drivers/leds/led-core.c index 385e78af1dac..073c547068cc 100644 --- a/drivers/leds/led-core.c +++ b/drivers/leds/led-core.c @@ -303,24 +303,31 @@ EXPORT_SYMBOL_GPL(led_stop_software_blink); void led_set_brightness(struct led_classdev *led_cdev, unsigned int brightness) { - /* - * If software blink is active, delay brightness setting - * until the next timer tick. - */ - if (test_bit(LED_BLINK_SW, &led_cdev->work_flags)) { + if (brightness) { + /* + * If software blink disable is pending, also queue brightness setting. + * If software blink is active, delay brightness setting + * until the next timer tick. + */ + if (test_bit(LED_SET_BRIGHTNESS, &led_cdev->work_flags) || + test_bit(LED_BLINK_DISABLE, &led_cdev->work_flags)) { + led_cdev->delayed_set_value = brightness; + set_bit(LED_SET_BRIGHTNESS, &led_cdev->work_flags); + queue_work(led_cdev->wq, &led_cdev->set_brightness_work); + return; + } else if (test_bit(LED_BLINK_SW, &led_cdev->work_flags)) { + led_cdev->new_blink_brightness = brightness; + set_bit(LED_BLINK_BRIGHTNESS_CHANGE, &led_cdev->work_flags); + return; + } + } else if (test_bit(LED_BLINK_SW, &led_cdev->work_flags)) { /* * If we need to disable soft blinking delegate this to the * work queue task to avoid problems in case we are called * from hard irq context. */ - if (!brightness) { - set_bit(LED_BLINK_DISABLE, &led_cdev->work_flags); - queue_work(led_cdev->wq, &led_cdev->set_brightness_work); - } else { - set_bit(LED_BLINK_BRIGHTNESS_CHANGE, - &led_cdev->work_flags); - led_cdev->new_blink_brightness = brightness; - } + set_bit(LED_BLINK_DISABLE, &led_cdev->work_flags); + queue_work(led_cdev->wq, &led_cdev->set_brightness_work); return; }