---
id: CVE-2026-23368
title: 'net: phy: register phy led_triggers during probe to avoid AB-BA deadlock'
summary: |-
  In the Linux kernel, the following vulnerability has been resolved:

  net: phy: register phy led_triggers during probe to avoid AB-BA deadlock

  There is an AB-BA deadlock when both LEDS_TRIGGER_NETDEV and
  LED_TRIGGER_PHY are enabled:

  [ 1…
severity: none
vendor: Linux
product: Linux
affected:
  - >-
    Linux >= 06f502f57d0d7728f9fa0f157ec5e4111ddb98f6 <
    2b01518eabace18f7ec8b4cafd52082303080dca
  - >-
    Linux >= 06f502f57d0d7728f9fa0f157ec5e4111ddb98f6 <
    305afdd02ff3e694c165457793104710ec0728e5
  - >-
    Linux >= 06f502f57d0d7728f9fa0f157ec5e4111ddb98f6 <
    c6ffc2d2338d325e1edd0c702e3ee623aa5fdc6a
  - >-
    Linux >= 06f502f57d0d7728f9fa0f157ec5e4111ddb98f6 <
    c33523b8fd2d4c504ada18cd93f511f2a8f84217
  - >-
    Linux >= 06f502f57d0d7728f9fa0f157ec5e4111ddb98f6 <
    241cd64cf2e32b28ead151b1795cd8fef2b6e482
  - >-
    Linux >= 06f502f57d0d7728f9fa0f157ec5e4111ddb98f6 <
    2764dcb3c35de4410f642afc62cf979727470575
  - >-
    Linux >= 06f502f57d0d7728f9fa0f157ec5e4111ddb98f6 <
    cde2d0b5ab5d03b5b6f17d4f654d8b30ccf36757
  - >-
    Linux >= 06f502f57d0d7728f9fa0f157ec5e4111ddb98f6 <
    c8dbdc6e380e7e96a51706db3e4b7870d8a9402d
  - Linux 4.16
published: '2026-03-25'
updated: '2026-09-08'
sourceUpdated: '2026-09-08T08:45:47.019Z'
source: CVEORG
sourceUrl: 'https://www.cve.org/CVERecord?id=CVE-2026-23368'
references:
  - url: 'https://git.kernel.org/stable/c/2b01518eabace18f7ec8b4cafd52082303080dca'
  - url: 'https://git.kernel.org/stable/c/305afdd02ff3e694c165457793104710ec0728e5'
  - url: 'https://git.kernel.org/stable/c/c6ffc2d2338d325e1edd0c702e3ee623aa5fdc6a'
  - url: 'https://git.kernel.org/stable/c/c33523b8fd2d4c504ada18cd93f511f2a8f84217'
  - url: 'https://git.kernel.org/stable/c/241cd64cf2e32b28ead151b1795cd8fef2b6e482'
  - url: 'https://git.kernel.org/stable/c/2764dcb3c35de4410f642afc62cf979727470575'
  - url: 'https://git.kernel.org/stable/c/cde2d0b5ab5d03b5b6f17d4f654d8b30ccf36757'
  - url: 'https://git.kernel.org/stable/c/c8dbdc6e380e7e96a51706db3e4b7870d8a9402d'
tags:
  - cve.org
epss: 0.00099
epssPercentile: 0.00773
ingestedAt: '2026-09-08T15:33:26.992Z'
---

## Overview

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

net: phy: register phy led_triggers during probe to avoid AB-BA deadlock

There is an AB-BA deadlock when both LEDS_TRIGGER_NETDEV and
LED_TRIGGER_PHY are enabled:

[ 1362.049207] [<8054e4b8>] led_trigger_register+0x5c/0x1fc             <-- Trying to get lock "triggers_list_lock" via down_write(&triggers_list_lock);
[ 1362.054536] [<80662830>] phy_led_triggers_register+0xd0/0x234
[ 1362.060329] [<8065e200>] phy_attach_direct+0x33c/0x40c
[ 1362.065489] [<80651fc4>] phylink_fwnode_phy_connect+0x15c/0x23c
[ 1362.071480] [<8066ee18>] mtk_open+0x7c/0xba0
[ 1362.075849] [<806d714c>] __dev_open+0x280/0x2b0
[ 1362.080384] [<806d7668>] __dev_change_flags+0x244/0x24c
[ 1362.085598] [<806d7698>] dev_change_flags+0x28/0x78
[ 1362.090528] [<807150e4>] dev_ioctl+0x4c0/0x654                       <-- Hold lock "rtnl_mutex" by calling rtnl_lock();
[ 1362.094985] [<80694360>] sock_ioctl+0x2f4/0x4e0
[ 1362.099567] [<802e9c4c>] sys_ioctl+0x32c/0xd8c
[ 1362.104022] [<80014504>] syscall_common+0x34/0x58

Here LED_TRIGGER_PHY is registering LED triggers during phy_attach
while holding RTNL and then taking triggers_list_lock.

[ 1362.191101] [<806c2640>] register_netdevice_notifier+0x60/0x168      <-- Trying to get lock "rtnl_mutex" via rtnl_lock();
[ 1362.197073] [<805504ac>] netdev_trig_activate+0x194/0x1e4
[ 1362.202490] [<8054e28c>] led_trigger_set+0x1d4/0x360                 <-- Hold lock "triggers_list_lock" by down_read(&triggers_list_lock);
[ 1362.207511] [<8054eb38>] led_trigger_write+0xd8/0x14c
[ 1362.212566] [<80381d98>] sysfs_kf_bin_write+0x80/0xbc
[ 1362.217688] [<8037fcd8>] kernfs_fop_write_iter+0x17c/0x28c
[ 1362.223174] [<802cbd70>] vfs_write+0x21c/0x3c4
[ 1362.227712] [<802cc0c4>] ksys_write+0x78/0x12c
[ 1362.232164] [<80014504>] syscall_common+0x34/0x58

Here LEDS_TRIGGER_NETDEV is being enabled on an LED. It first takes
triggers_list_lock and then RTNL. A classical AB-BA deadlock.

phy_led_triggers_registers() does not require the RTNL, it does not
make any calls into the network stack which require protection. There
is also no requirement the PHY has been attached to a MAC, the
triggers only make use of phydev state. This allows the call to
phy_led_triggers_registers() to be placed elsewhere. PHY probe() and
release() don't hold RTNL, so solving the AB-BA deadlock.

## Affected

- `Linux >= 06f502f57d0d7728f9fa0f157ec5e4111ddb98f6 < 2b01518eabace18f7ec8b4cafd52082303080dca`
- `Linux >= 06f502f57d0d7728f9fa0f157ec5e4111ddb98f6 < 305afdd02ff3e694c165457793104710ec0728e5`
- `Linux >= 06f502f57d0d7728f9fa0f157ec5e4111ddb98f6 < c6ffc2d2338d325e1edd0c702e3ee623aa5fdc6a`
- `Linux >= 06f502f57d0d7728f9fa0f157ec5e4111ddb98f6 < c33523b8fd2d4c504ada18cd93f511f2a8f84217`
- `Linux >= 06f502f57d0d7728f9fa0f157ec5e4111ddb98f6 < 241cd64cf2e32b28ead151b1795cd8fef2b6e482`
- `Linux >= 06f502f57d0d7728f9fa0f157ec5e4111ddb98f6 < 2764dcb3c35de4410f642afc62cf979727470575`
- `Linux >= 06f502f57d0d7728f9fa0f157ec5e4111ddb98f6 < cde2d0b5ab5d03b5b6f17d4f654d8b30ccf36757`
- `Linux >= 06f502f57d0d7728f9fa0f157ec5e4111ddb98f6 < c8dbdc6e380e7e96a51706db3e4b7870d8a9402d`
- `Linux 4.16`

## Remediation

Refer to the linked advisories for vendor-supplied fixes and affected version ranges.