[PATCH v4 08/12] leds: trigger: Do not attach trigger to a removing LED
From: Rong Zhang <hidden>
Date: 2026-08-01 17:30:19
Also in:
chrome-platform, linux-leds, lkml, netdev, platform-driver-x86
Subsystem:
led subsystem, the rest · Maintainers:
Lee Jones, Pavel Machek, Linus Torvalds
Currently the LED trigger core knows little about an LED's removal as the LED_UNREGISTERING flag is set too late. This could lead to a race condition where a trigger may be attached to a removing LED right after its previous trigger is removed. Set the flag at the very beginning of led_classdev_unregister(), and check the flag before attaching a trigger. Signed-off-by: Rong Zhang <redacted> --- Changes in v4: - New patch in the series to address concerns from Sashiko - Without it, following patches will expose a race condition - https://sashiko.dev/#/patchset/20260719-leds-trigger-hw-changed-v3-0-5fb55722e36e@rong.moe?part=8 --- drivers/leds/led-class.c | 4 ++-- drivers/leds/led-triggers.c | 3 +++ 2 files changed, 5 insertions(+), 2 deletions(-)
diff --git a/drivers/leds/led-class.c b/drivers/leds/led-class.c
index 2460fcf0c469..4158337896bc 100644
--- a/drivers/leds/led-class.c
+++ b/drivers/leds/led-class.c@@ -631,6 +631,8 @@ void led_classdev_unregister(struct led_classdev *led_cdev) if (IS_ERR_OR_NULL(led_cdev->dev)) return; + led_cdev->flags |= LED_UNREGISTERING; + #ifdef CONFIG_LEDS_TRIGGERS down_write(&led_cdev->trigger_lock); if (led_cdev->trigger)
@@ -638,8 +640,6 @@ void led_classdev_unregister(struct led_classdev *led_cdev) up_write(&led_cdev->trigger_lock); #endif - led_cdev->flags |= LED_UNREGISTERING; - /* Stop blinking */ led_stop_software_blink(led_cdev);
diff --git a/drivers/leds/led-triggers.c b/drivers/leds/led-triggers.c
index cb49a02a8b3c..64bc95d0bfeb 100644
--- a/drivers/leds/led-triggers.c
+++ b/drivers/leds/led-triggers.c@@ -200,6 +200,9 @@ int led_trigger_set(struct led_classdev *led_cdev, struct led_trigger *trig) const char *name; int ret; + if ((led_cdev->flags & LED_UNREGISTERING) && trig) + return -ENODEV; + if (!led_cdev->trigger && !trig) return 0;
--
2.53.0