---
id: CVE-2026-98109
title: |-
  In the Linux kernel, the following vulnerability has been resolved:

  Bluetooth: hci_core: Fix race condition during device registration

  In hci_register_dev(), the power_on work item is queued to
  hdev->req_workqueue before initializing h…
summary: |-
  In the Linux kernel, the following vulnerability has been resolved:

  Bluetooth: hci_core: Fix race condition during device registration

  In hci_register_dev(), the power_on work item is queued to
  hdev->req_workqueue before initializing h…
severity: none
vendor: Linux
product: Linux
affected:
  - >-
    Linux >= 9e14606d8f38ea52a38c27692a9c1513c987a5da <
    b1faf348c29e6f8302ec7769cbf1c1ef05be014f
  - >-
    Linux >= 9e14606d8f38ea52a38c27692a9c1513c987a5da <
    a11ebe8dc0333fb870bbbb656b34690e87ee3f98
  - >-
    Linux >= 9e14606d8f38ea52a38c27692a9c1513c987a5da <
    d427b1c71d9798083e954d3c13469dc0a2305868
  - >-
    Linux >= 9e14606d8f38ea52a38c27692a9c1513c987a5da <
    57938bbdb9bf7fd41cbd5cd509ec10c4b22bec18
  - Linux f9965f7f38c90449a5fb26edb8a7d22b1dcf0283
  - Linux 80fe27811c56ecd3896c3d511ab8298146071d98
  - Linux >= 6.4.16 < 6.5
  - Linux >= 6.5.3 < 6.6
  - Linux 6.6
published: '2026-09-25'
updated: '2026-09-25'
sourceUpdated: '2026-09-25T11:17:41.977'
source: NVD
sourceUrl: 'https://nvd.nist.gov/vuln/detail/CVE-2026-98109'
references:
  - url: 'https://git.kernel.org/stable/c/57938bbdb9bf7fd41cbd5cd509ec10c4b22bec18'
    label: 416baaa9-dc9f-4396-8d5f-8c081fb06d67
  - url: 'https://git.kernel.org/stable/c/a11ebe8dc0333fb870bbbb656b34690e87ee3f98'
    label: 416baaa9-dc9f-4396-8d5f-8c081fb06d67
  - url: 'https://git.kernel.org/stable/c/b1faf348c29e6f8302ec7769cbf1c1ef05be014f'
    label: 416baaa9-dc9f-4396-8d5f-8c081fb06d67
  - url: 'https://git.kernel.org/stable/c/d427b1c71d9798083e954d3c13469dc0a2305868'
    label: 416baaa9-dc9f-4396-8d5f-8c081fb06d67
tags:
  - nvd
  - cve.org
ingestedAt: '2026-09-25T11:06:38.824Z'
---

## Overview

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

Bluetooth: hci_core: Fix race condition during device registration

In hci_register_dev(), the power_on work item is queued to
hdev->req_workqueue before initializing hdev->adv_monitors_idr and
registering the MSFT extension via msft_register(). For devices marked with
quirks such as HCI_QUIRK_RAW_DEVICE, the HCI_UNCONFIGURED flag is set on
the device. When the power_on work item runs concurrently on another CPU,
hci_power_on() detects that the device is unconfigured and immediately
invokes hci_dev_do_close(), which calls msft_do_close().

Concurrently, msft_register() allocates the msft structure and exposes it
to hdev->msft_data prior to calling mutex_init(&msft->filter_lock). If
msft_do_close() executes while hdev->msft_data is already assigned but the
mutex has not yet been initialized, mutex_lock(&msft->filter_lock) operates
on an uninitialized mutex, triggering a DEBUG_LOCKS warning:

DEBUG_LOCKS_WARN_ON(lock->magic != lock)
WARNING: kernel/locking/mutex.c:625 at __mutex_lock_common
kernel/locking/mutex.c:625 [inline]
WARNING: kernel/locking/mutex.c:625 at __mutex_lock+0x12d8/0x1550
kernel/locking/mutex.c:821
...
Call Trace:
 <TASK>
 msft_do_close+0x308/0x7b0 net/bluetooth/msft.c:693
 hci_dev_close_sync+0x86b/0x10a0 net/bluetooth/hci_sync.c:5522
 hci_dev_do_close net/bluetooth/hci_core.c:499 [inline]
 hci_power_on+0x32c/0x750 net/bluetooth/hci_core.c:937
 process_one_work kernel/workqueue.c:3322 [inline]
 process_scheduled_works+0xa8e/0x14e0 kernel/workqueue.c:3405
 worker_thread+0x92d/0xe10 kernel/workqueue.c:3486
 kthread+0x388/0x470 kernel/kthread.c:436
 ret_from_fork+0x514/0xb70 arch/x86/kernel/process.c:158
 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245
 </TASK>

Fix this by moving the queue_work() call in hci_register_dev() to after
idr_init(&hdev->adv_monitors_idr) and msft_register(hdev) so that device
structures and extensions are fully initialized before asynchronous tasks
can access them. Additionally, assign hdev->msft_data in msft_register()
only after mutex_init(&msft->filter_lock) has completed.

## Remediation

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