CVE-2026-23101

In the Linux kernel, the following vulnerability has been resolved:

leds: led-class: Only Add LED to leds_list when it is fully ready

Before this change the LED was added to leds_list before led_init_core()

gets called adding it the list before led_classdev.set_brightness_work gets

initialized.

This leaves a window where led_trigger_register() of a LED's default

trigger will call led_trigger_set() which calls led_set_brightness()

which in turn will end up queueing the *uninitialized*

led_classdev.set_brightness_work.

This race gets hit by the lenovo-thinkpad-t14s EC driver which registers

2 LEDs with a default trigger provided by snd_ctl_led.ko in quick

succession. The first led_classdev_register() causes an async modprobe of

snd_ctl_led to run and that async modprobe manages to exactly hit

the window where the second LED is on the leds_list without led_init_core()

being called for it, resulting in:

------------[ cut here ]------------

WARNING: CPU: 11 PID: 5608 at kernel/workqueue.c:4234 __flush_work+0x344/0x390

Hardware name: LENOVO 21N2S01F0B/21N2S01F0B, BIOS N42ET93W (2.23 ) 09/01/2025

...

Call trace:

__flush_work+0x344/0x390 (P)

flush_work+0x2c/0x50

led_trigger_set+0x1c8/0x340

led_trigger_register+0x17c/0x1c0

led_trigger_register_simple+0x84/0xe8

snd_ctl_led_init+0x40/0xf88 [snd_ctl_led]

do_one_initcall+0x5c/0x318

do_init_module+0x9c/0x2b8

load_module+0x7e0/0x998

Close the race window by moving the adding of the LED to leds_list to

after the led_init_core() call.