---
id: CVE-2025-71221
title: |-
  In the Linux kernel, the following vulnerability has been resolved:

  dmaengine: mmp_pdma: Fix race condition in mmp_pdma_residue()

  Add proper locking in mmp_pdma_residue() to prevent use-after-free when
  accessing descriptor list and des…
summary: |-
  In the Linux kernel, the following vulnerability has been resolved:

  dmaengine: mmp_pdma: Fix race condition in mmp_pdma_residue()

  Add proper locking in mmp_pdma_residue() to prevent use-after-free when
  accessing descriptor list and des…
severity: high
cvss: 7.8
cvssVector: 'CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H'
cwe:
  - CWE-362
vendor: linux
product: linux_kernel
affected:
  - 'linux_kernel >= 3.16, < 6.18.10'
  - linux_kernel = 6.19
patched:
  - linux_kernel 6.18.10
published: '2026-02-14'
updated: '2026-10-15'
sourceUpdated: '2026-10-15T02:18:25.190'
source: NVD
sourceUrl: 'https://nvd.nist.gov/vuln/detail/CVE-2025-71221'
references:
  - url: 'https://git.kernel.org/stable/c/3f0e0e2d9e752570041e95fd04635e2580097819'
    label: 416baaa9-dc9f-4396-8d5f-8c081fb06d67
  - url: 'https://git.kernel.org/stable/c/9f665b3c3d9a168410251f27a5d019b7bf93185c'
    label: 416baaa9-dc9f-4396-8d5f-8c081fb06d67
  - url: 'https://git.kernel.org/stable/c/a143545855bc2c6e1330f6f57ae375ac44af00a7'
    label: 416baaa9-dc9f-4396-8d5f-8c081fb06d67
  - url: 'https://git.kernel.org/stable/c/dfb5e05227745de43b7fd589721817a4337c970d'
    label: 416baaa9-dc9f-4396-8d5f-8c081fb06d67
  - url: 'https://git.kernel.org/stable/c/eba0c75670c022cb1f948600db972524bcfe8166'
    label: 416baaa9-dc9f-4396-8d5f-8c081fb06d67
  - url: 'https://git.kernel.org/stable/c/fc023b8fab057f0c910856ff36d3e12a30b7af4a'
    label: 416baaa9-dc9f-4396-8d5f-8c081fb06d67
  - url: 'https://cert-portal.siemens.com/productcert/html/ssa-019113.html'
    label: 0b142b55-0307-4c5a-b3c9-f314f3fb7c5e
  - url: 'https://cert-portal.siemens.com/productcert/html/ssa-082556.html'
    label: 0b142b55-0307-4c5a-b3c9-f314f3fb7c5e
  - url: 'https://cert-portal.siemens.com/productcert/html/ssa-457936.html'
    label: 0b142b55-0307-4c5a-b3c9-f314f3fb7c5e
tags:
  - nvd
  - cve.org
epss: 0.00116
epssPercentile: 0.01564
ingestedAt: '2026-09-08T15:33:26.994Z'
---

## Overview

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

dmaengine: mmp_pdma: Fix race condition in mmp_pdma_residue()

Add proper locking in mmp_pdma_residue() to prevent use-after-free when
accessing descriptor list and descriptor contents.

The race occurs when multiple threads call tx_status() while the tasklet
on another CPU is freeing completed descriptors:

CPU 0                              CPU 1
-----                              -----
mmp_pdma_tx_status()
mmp_pdma_residue()
  -> NO LOCK held
     list_for_each_entry(sw, ..)
                                   DMA interrupt
                                   dma_do_tasklet()
                                     -> spin_lock(&desc_lock)
                                        list_move(sw->node, ...)
                                        spin_unlock(&desc_lock)
  |                                     dma_pool_free(sw) <- FREED!
  -> access sw->desc <- UAF!

This issue can be reproduced when running dmatest on the same channel with
multiple threads (threads_per_chan > 1).

Fix by protecting the chain_running list iteration and descriptor access
with the chan->desc_lock spinlock.

## Affected

- `linux_kernel >= 3.16, < 6.18.10`
- `linux_kernel = 6.19`

## Remediation

Upgrade past the affected range:

- `linux_kernel 6.18.10`