---
id: CVE-2026-74365
title: 'nvdimm/btt: Handle preemption in BTT lane acquisition'
summary: |-
  In the Linux kernel, the following vulnerability has been resolved:

  nvdimm/btt: Handle preemption in BTT lane acquisition

  BTT lanes serialize access to per-lane metadata and workspace state
  during BTT I/O. The btt-check unit test repor…
severity: high
cvss: 7.3
cvssVector: 'CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:L'
cvssSource: cna
vendor: Linux
product: Linux
affected:
  - >-
    Linux >= f23859748e3d530217b197e146a9ac84faf0a282 <
    fd7a97b2514cfc4b4cc067a27dd39bde2a8b1735
  - >-
    Linux >= 6f50b414f1a0d790f11a6438a3ad6d0577eb2c18 <
    73e35c1bdfa160b41fdbe204e02325f0687de506
  - >-
    Linux >= 36c75ce3bd299878fd9b238e9803d3817ddafbf3 <
    417918783bcfe0be135019df16a267b3af442efd
  - >-
    Linux >= 36c75ce3bd299878fd9b238e9803d3817ddafbf3 <
    5c53406098b599c420b031e6ec5ba8a2f3794c50
  - >-
    Linux >= 36c75ce3bd299878fd9b238e9803d3817ddafbf3 <
    4eafa810b042d985ec6bbf5b514414e73cee6f6f
  - >-
    Linux >= 36c75ce3bd299878fd9b238e9803d3817ddafbf3 <
    8d4b989d9c9afe5f185aa5853b666fc4617afe9e
  - Linux 2577fece583c7c05cda7ad50dde7638c962665e1
  - Linux 40ba3fa21250e361bdd8f00800b3e2cb6160de95
  - Linux b0e7a935739f33ed2bd6868b89f97dd4c2683c26
  - Linux 66eb7b7f23dd9aec5356e7054dd3596ae7648ff5
  - Linux b27751fb1f271bbb78d5993c0b10011628e40e18
  - Linux >= 6.1.63 < 6.1.178
  - Linux >= 6.6.2 < 6.6.145
  - Linux >= 4.19.299 < 4.20
  - Linux >= 5.4.261 < 5.5
  - Linux >= 5.10.201 < 5.11
  - Linux >= 5.15.139 < 5.16
  - Linux >= 6.5.12 < 6.6
  - Linux 6.7
ssvc:
  exploitation: none
  automatable: 'no'
  technicalImpact: total
  timestamp: '2026-10-16T18:54:37.742896Z'
published: '2026-08-15'
updated: '2026-10-16'
sourceUpdated: '2026-10-16T18:55:35.765Z'
source: CVEORG
sourceUrl: 'https://www.cve.org/CVERecord?id=CVE-2026-74365'
references:
  - url: 'https://git.kernel.org/stable/c/fd7a97b2514cfc4b4cc067a27dd39bde2a8b1735'
  - url: 'https://git.kernel.org/stable/c/73e35c1bdfa160b41fdbe204e02325f0687de506'
  - url: 'https://git.kernel.org/stable/c/417918783bcfe0be135019df16a267b3af442efd'
  - url: 'https://git.kernel.org/stable/c/5c53406098b599c420b031e6ec5ba8a2f3794c50'
  - url: 'https://git.kernel.org/stable/c/4eafa810b042d985ec6bbf5b514414e73cee6f6f'
  - url: 'https://git.kernel.org/stable/c/8d4b989d9c9afe5f185aa5853b666fc4617afe9e'
tags:
  - cve.org
epss: 0.0018
epssPercentile: 0.07043
ingestedAt: '2026-10-16T19:46:24.373Z'
---

## Overview

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

nvdimm/btt: Handle preemption in BTT lane acquisition

BTT lanes serialize access to per-lane metadata and workspace state
during BTT I/O. The btt-check unit test reports data mismatches during
BTT writes due to a race in lane acquisition that can lead to silent
data corruption.

The existing lane model uses a spinlock together with a per-CPU
recursion count. That recursion model stopped being valid after BTT
lanes became preemptible: another task can run on the same CPU,
observe a non-zero recursion count, bypass locking, and use the same
lane concurrently.

BTT lanes are also held across arena_write_bytes() calls. That path
reaches nsio_rw_bytes(), which flushes writes with nvdimm_flush().
Some provider flush callbacks can sleep, making a spinlock the wrong
primitive for the lane lifetime.

Replace the spinlock-based recursion model with a dynamically
allocated per-lane mutex array and take the lane lock
unconditionally.

Add might_sleep() to catch any future atomic-context caller.

Found with the ndctl unit test btt-check.sh.

## Affected

- `Linux >= f23859748e3d530217b197e146a9ac84faf0a282 < fd7a97b2514cfc4b4cc067a27dd39bde2a8b1735`
- `Linux >= 6f50b414f1a0d790f11a6438a3ad6d0577eb2c18 < 73e35c1bdfa160b41fdbe204e02325f0687de506`
- `Linux >= 36c75ce3bd299878fd9b238e9803d3817ddafbf3 < 417918783bcfe0be135019df16a267b3af442efd`
- `Linux >= 36c75ce3bd299878fd9b238e9803d3817ddafbf3 < 5c53406098b599c420b031e6ec5ba8a2f3794c50`
- `Linux >= 36c75ce3bd299878fd9b238e9803d3817ddafbf3 < 4eafa810b042d985ec6bbf5b514414e73cee6f6f`
- `Linux >= 36c75ce3bd299878fd9b238e9803d3817ddafbf3 < 8d4b989d9c9afe5f185aa5853b666fc4617afe9e`
- `Linux 2577fece583c7c05cda7ad50dde7638c962665e1`
- `Linux 40ba3fa21250e361bdd8f00800b3e2cb6160de95`
- `Linux b0e7a935739f33ed2bd6868b89f97dd4c2683c26`
- `Linux 66eb7b7f23dd9aec5356e7054dd3596ae7648ff5`
- `Linux b27751fb1f271bbb78d5993c0b10011628e40e18`
- `Linux >= 6.1.63 < 6.1.178`
- `Linux >= 6.6.2 < 6.6.145`
- `Linux >= 4.19.299 < 4.20`
- `Linux >= 5.4.261 < 5.5`
- `Linux >= 5.10.201 < 5.11`
- `Linux >= 5.15.139 < 5.16`
- `Linux >= 6.5.12 < 6.6`
- `Linux 6.7`

## Remediation

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