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leds: class: Always protect brightness_show() with led_access

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The led_classdev_register_ext() protects transient states when
registering with the led_access mutex and relies on all sensitive sysfs
attribute callbacks holding the mutex to prevent exposing transient
states.

The Fixes: commit broke this as it accessed trigger_lock without holding
led_access. Fix it by protecting brightness_show() with led_access in
all code paths.

Fixes: b819dc7d8f ("leds: core: Report ENODATA for brightness of hardware controlled LED")
Signed-off-by: Rong Zhang <i@rong.moe>
Link: https://patch.msgid.link/20260921-leds-trigger-hw-changed-v7-1-fe3cdb6dec51@rong.moe
Signed-off-by: Lee Jones <lee@kernel.org>
This commit is contained in:
Rong Zhang 2026-09-21 03:40:15 +08:00 committed by Lee Jones
parent d494855128
commit 6887f40dad
1 changed files with 6 additions and 6 deletions
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12
drivers/leds/led-class.c
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@ -43,13 +43,13 @@ static ssize_t brightness_show(struct device *dev,
struct led_classdev *led_cdev = dev_get_drvdata(dev);
unsigned int brightness;
if (led_trigger_is_hw_controlled(led_cdev))
return -ENODATA;
scoped_guard(mutex, &led_cdev->led_access) {
if (led_trigger_is_hw_controlled(led_cdev))
return -ENODATA;
mutex_lock(&led_cdev->led_access);
led_update_brightness(led_cdev);
brightness = led_cdev->brightness;
mutex_unlock(&led_cdev->led_access);
led_update_brightness(led_cdev);
brightness = led_cdev->brightness;
}
return sysfs_emit(buf, "%u\n", brightness);
}