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Hans de Goede 7882262816 leds: led-class: Only Add LED to leds_list when it is fully ready
commit d1883cefd3 upstream.

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.

Cc: stable@vger.kernel.org
Fixes: d23a22a74f ("leds: delay led_set_brightness if stopping soft-blink")
Signed-off-by: Hans de Goede <johannes.goede@oss.qualcomm.com>
Reviewed-by: Sebastian Reichel <sre@kernel.org>
Link: https://patch.msgid.link/20251211163727.366441-1-johannes.goede@oss.qualcomm.com
Signed-off-by: Lee Jones <lee@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
History 2026-01-30 10:32:22 +01:00
arch x86: make page fault handling disable interrupts properly 2026-01-30 10:32:22 +01:00
block block: zero non-PI portion of auto integrity buffer 2026-01-23 11:21:16 +01:00
certs sign-file,extract-cert: use pkcs11 provider for OPENSSL MAJOR >= 3 2024-09-20 19:52:48 +03:00
crypto crypto: authencesn - reject too-short AAD (assoclen<8) to match ESP/ESN spec 2026-01-30 10:32:12 +01:00
Documentation fou: Don't allow 0 for FOU_ATTR_IPPROTO. 2026-01-30 10:32:12 +01:00
drivers leds: led-class: Only Add LED to leds_list when it is fully ready 2026-01-30 10:32:22 +01:00
fs fs/writeback: skip AS_NO_DATA_INTEGRITY mappings in wait_sb_inodes() 2026-01-30 10:32:15 +01:00
include mm/hugetlb: fix hugetlb_pmd_shared() 2026-01-30 10:32:15 +01:00
init printk changes for 6.18 2025-10-04 11:13:11 -07:00
io_uring io_uring/io-wq: check IO_WQ_BIT_EXIT inside work run loop 2026-01-30 10:32:15 +01:00
ipc namespace-6.18-rc1 2025-09-29 11:20:29 -07:00
kernel sched/fair: Fix pelt clock sync when entering idle 2026-01-30 10:32:20 +01:00
lib lib/buildid: use __kernel_read() for sleepable context 2026-01-23 11:21:25 +01:00
LICENSES LICENSES: Replace the obsolete address of the FSF in the GFDL-1.2 2025-07-24 11:15:39 +02:00
mm mm: restore per-memcg proactive reclaim with !CONFIG_NUMA 2026-01-30 10:32:15 +01:00
net net/sched: act_ife: avoid possible NULL deref 2026-01-30 10:32:21 +01:00
rust rust: bitops: fix missing _find_* functions on 32-bit ARM 2026-01-23 11:21:12 +01:00
samples samples/ftrace: Adjust LoongArch register restore order in direct calls 2026-01-08 10:17:11 +01:00
scripts kconfig: fix static linking of nconf 2026-01-30 10:32:16 +01:00
security keys/trusted_keys: fix handle passed to tpm_buf_append_name during unseal 2026-01-30 10:32:22 +01:00
sound ALSA: usb: Increase volume range that triggers a warning 2026-01-30 10:32:17 +01:00
tools vsock/test: fix seqpacket message bounds test 2026-01-30 10:32:21 +01:00
usr gen_init_cpio: Ignore fsync() returning EINVAL on pipes 2025-10-07 09:53:05 -07:00
virt KVM: Fix last_boosted_vcpu index assignment bug 2026-01-02 12:57:21 +01:00
.clang-format memblock: drop for_each_free_mem_pfn_range_in_zone_from() 2025-09-14 08:49:03 +03:00
.clippy.toml rust: clean Rust 1.88.0's warning about clippy::disallowed_macros configuration 2025-05-07 00:11:47 +02:00
.cocciconfig scripts: add Linux .cocciconfig for coccinelle 2016-07-22 12:13:39 +02:00
.editorconfig .editorconfig: remove trim_trailing_whitespace option 2024-06-13 16:47:52 +02:00
.get_maintainer.ignore MAINTAINERS: remove Alyssa Rosenzweig 2025-09-18 21:17:31 +02:00
.gitattributes .gitattributes: set diff driver for Rust source code files 2023-05-31 17:48:25 +02:00
.gitignore .gitignore: ignore compile_commands.json globally 2025-08-12 15:53:55 -07:00
.mailmap 8 hotfixes. 4 are cc:stable, 7 are against mm/. 2025-11-26 12:38:05 -08:00
.pylintrc tools: docs: parse-headers.py: move it from sphinx dir 2025-08-29 15:54:42 -06:00
.rustfmt.toml rust: add .rustfmt.toml 2022-09-28 09:02:20 +02:00
COPYING COPYING: state that all contributions really are covered by this file 2020-02-10 13:32:20 -08:00
CREDITS MAINTAINERS: mark ISDN subsystem as orphan 2025-10-27 17:49:45 -07:00
Kbuild sched: Make migrate_{en,dis}able() inline 2025-09-25 09:57:16 +02:00
Kconfig io_uring: Rename KConfig to Kconfig 2025-02-19 14:53:27 -07:00
MAINTAINERS soc: fixes for 6.18, part 4 2025-11-28 09:57:31 -08:00
Makefile Linux 6.18.7 2026-01-23 11:21:37 +01:00
README README: Fix spelling 2024-03-18 03:36:32 -06:00

Linux kernel
============

There are several guides for kernel developers and users. These guides can
be rendered in a number of formats, like HTML and PDF. Please read
Documentation/admin-guide/README.rst first.

In order to build the documentation, use ``make htmldocs`` or
``make pdfdocs``.  The formatted documentation can also be read online at:

    https://www.kernel.org/doc/html/latest/

There are various text files in the Documentation/ subdirectory,
several of them using the reStructuredText markup notation.

Please read the Documentation/process/changes.rst file, as it contains the
requirements for building and running the kernel, and information about
the problems which may result by upgrading your kernel.