---
id: CVE-2026-23348
title: 'cxl: Fix race of nvdimm_bus object when creating nvdimm objects'
summary: |-
  In the Linux kernel, the following vulnerability has been resolved:

  cxl: Fix race of nvdimm_bus object when creating nvdimm objects

  Found issue during running of cxl-translate.sh unit test. Adding a 3s
  sleep right before the test seems…
severity: none
vendor: Linux
product: Linux
affected:
  - >-
    Linux >= 8fdcb1704f61a8fd9be0f3849a174d084def0666 <
    5fc4e150c5ada5f7d20d8f9f1b351f10481fbdf7
  - >-
    Linux >= 8fdcb1704f61a8fd9be0f3849a174d084def0666 <
    5b230daeee420833287cc77314439903e5312f10
  - >-
    Linux >= 8fdcb1704f61a8fd9be0f3849a174d084def0666 <
    96a1fd0d84b17360840f344826897fa71049870e
  - Linux 5.14
ssvc:
  exploitation: none
  automatable: 'no'
  technicalImpact: partial
  timestamp: '2026-11-05T21:27:33.479828Z'
published: '2026-03-25'
updated: '2026-11-05'
sourceUpdated: '2026-11-05T21:33:41.580Z'
source: CVEORG
sourceUrl: 'https://www.cve.org/CVERecord?id=CVE-2026-23348'
references:
  - url: 'https://git.kernel.org/stable/c/5fc4e150c5ada5f7d20d8f9f1b351f10481fbdf7'
  - url: 'https://git.kernel.org/stable/c/5b230daeee420833287cc77314439903e5312f10'
  - url: 'https://git.kernel.org/stable/c/96a1fd0d84b17360840f344826897fa71049870e'
tags:
  - cve.org
epss: 0.00091
epssPercentile: 0.00471
ingestedAt: '2026-11-05T22:38:32.119Z'
---

## Overview

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

cxl: Fix race of nvdimm_bus object when creating nvdimm objects

Found issue during running of cxl-translate.sh unit test. Adding a 3s
sleep right before the test seems to make the issue reproduce fairly
consistently. The cxl_translate module has dependency on cxl_acpi and
causes orphaned nvdimm objects to reprobe after cxl_acpi is removed.
The nvdimm_bus object is registered by the cxl_nvb object when
cxl_acpi_probe() is called. With the nvdimm_bus object missing,
__nd_device_register() will trigger NULL pointer dereference when
accessing the dev->parent that points to &nvdimm_bus->dev.

[  192.884510] BUG: kernel NULL pointer dereference, address: 000000000000006c
[  192.895383] Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS edk2-20250812-19.fc42 08/12/2025
[  192.897721] Workqueue: cxl_port cxl_bus_rescan_queue [cxl_core]
[  192.899459] RIP: 0010:kobject_get+0xc/0x90
[  192.924871] Call Trace:
[  192.925959]  <TASK>
[  192.926976]  ? pm_runtime_init+0xb9/0xe0
[  192.929712]  __nd_device_register.part.0+0x4d/0xc0 [libnvdimm]
[  192.933314]  __nvdimm_create+0x206/0x290 [libnvdimm]
[  192.936662]  cxl_nvdimm_probe+0x119/0x1d0 [cxl_pmem]
[  192.940245]  cxl_bus_probe+0x1a/0x60 [cxl_core]
[  192.943349]  really_probe+0xde/0x380

This patch also relies on the previous change where
devm_cxl_add_nvdimm_bridge() is called from drivers/cxl/pmem.c instead
of drivers/cxl/core.c to ensure the dependency of cxl_acpi on cxl_pmem.

1. Set probe_type of cxl_nvb to PROBE_FORCE_SYNCHRONOUS to ensure the
   driver is probed synchronously when add_device() is called.
2. Add a check in __devm_cxl_add_nvdimm_bridge() to ensure that the
   cxl_nvb driver is attached during cxl_acpi_probe().
3. Take the cxl_root uport_dev lock and the cxl_nvb->dev lock in
   devm_cxl_add_nvdimm() before checking nvdimm_bus is valid.
4. Set cxl_nvdimm flag to CXL_NVD_F_INVALIDATED so cxl_nvdimm_probe()
   will exit with -EBUSY.

The removal of cxl_nvdimm devices should prevent any orphaned devices
from probing once the nvdimm_bus is gone.

[ dj: Fixed 0-day reported kdoc issue. ]
[ dj: Fix cxl_nvb reference leak on error. Gregory (kreview-0811365) ]

## Affected

- `Linux >= 8fdcb1704f61a8fd9be0f3849a174d084def0666 < 5fc4e150c5ada5f7d20d8f9f1b351f10481fbdf7`
- `Linux >= 8fdcb1704f61a8fd9be0f3849a174d084def0666 < 5b230daeee420833287cc77314439903e5312f10`
- `Linux >= 8fdcb1704f61a8fd9be0f3849a174d084def0666 < 96a1fd0d84b17360840f344826897fa71049870e`
- `Linux 5.14`

## Remediation

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