{
  "schema_version": "1.6.1",
  "id": "RPI-CVE-2025-71221",
  "modified": "2026-10-09T11:39:44Z",
  "upstream": [
    "CVE-2025-71221"
  ],
  "published": "2026-02-14T16:28:50Z",
  "summary": "dmaengine: mmp_pdma: Fix race condition in mmp_pdma_residue()",
  "details": "In the Linux kernel, the following vulnerability has been resolved:\n\ndmaengine: mmp_pdma: Fix race condition in mmp_pdma_residue()\n\nAdd proper locking in mmp_pdma_residue() to prevent use-after-free when\naccessing descriptor list and descriptor contents.\n\nThe race occurs when multiple threads call tx_status() while the tasklet\non another CPU is freeing completed descriptors:\n\nCPU 0                              CPU 1\n-----                              -----\nmmp_pdma_tx_status()\nmmp_pdma_residue()\n  -> NO LOCK held\n     list_for_each_entry(sw, ..)\n                                   DMA interrupt\n                                   dma_do_tasklet()\n                                     -> spin_lock(&desc_lock)\n                                        list_move(sw->node, ...)\n                                        spin_unlock(&desc_lock)\n  |                                     dma_pool_free(sw) <- FREED!\n  -> access sw->desc <- UAF!\n\nThis issue can be reproduced when running dmatest on the same channel with\nmultiple threads (threads_per_chan > 1).\n\nFix by protecting the chain_running list iteration and descriptor access\nwith the chan->desc_lock spinlock.",
  "severity": [
    {
      "type": "CVSS_V3",
      "score": "CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H"
    }
  ],
  "affected": [
    {
      "package": {
        "ecosystem": "Raspberry Pi OS:12",
        "name": "linux"
      },
      "versions": [
        "1:6.1.47-1+rpt4"
      ],
      "ecosystem_specific": {
        "binaries": [
          {
            "binary_name": "linux-image-6.1.0-rpi3-rpi-2712",
            "binary_version": "1:6.1.47-1+rpt4"
          },
          {
            "binary_name": "linux-image-6.1.0-rpi3-rpi-v6",
            "binary_version": "1:6.1.47-1+rpt4"
          },
          {
            "binary_name": "linux-image-6.1.0-rpi3-rpi-v7",
            "binary_version": "1:6.1.47-1+rpt4"
          },
          {
            "binary_name": "linux-image-6.1.0-rpi3-rpi-v7l",
            "binary_version": "1:6.1.47-1+rpt4"
          },
          {
            "binary_name": "linux-image-6.1.0-rpi3-rpi-v8",
            "binary_version": "1:6.1.47-1+rpt4"
          }
        ]
      },
      "database_specific": {
        "per_version": {
          "1:6.1.47-1+rpt4": {
            "linux_commit": "655fc658a15ae7a6f37103754adb39ba52a9a14e",
            "upstream_version": "6.1.47",
            "assessment": "commit ancestry (strak rule)",
            "upstream_fixed": "6.1.167",
            "compiled_filter": false
          }
        }
      }
    }
  ],
  "references": [
    {
      "type": "ADVISORY",
      "url": "https://www.cve.org/CVERecord?id=CVE-2025-71221"
    },
    {
      "type": "FIX",
      "url": "https://git.kernel.org/stable/c/3f0e0e2d9e752570041e95fd04635e2580097819"
    },
    {
      "type": "FIX",
      "url": "https://git.kernel.org/stable/c/dfb5e05227745de43b7fd589721817a4337c970d"
    },
    {
      "type": "FIX",
      "url": "https://git.kernel.org/stable/c/eba0c75670c022cb1f948600db972524bcfe8166"
    },
    {
      "type": "FIX",
      "url": "https://git.kernel.org/stable/c/fc023b8fab057f0c910856ff36d3e12a30b7af4a"
    },
    {
      "type": "FIX",
      "url": "https://git.kernel.org/stable/c/9f665b3c3d9a168410251f27a5d019b7bf93185c"
    },
    {
      "type": "FIX",
      "url": "https://git.kernel.org/stable/c/a143545855bc2c6e1330f6f57ae375ac44af00a7"
    }
  ],
  "database_specific": {
    "source": "https://git.kernel.org/pub/scm/linux/security/vulns.git",
    "upstream_modified": "2026-08-05T12:19:11Z",
    "severity": {
      "source": "kernel CNA",
      "cvss_v3_score": 7.8,
      "cvss_v3_severity": "High",
      "scenario": "AV:L - The vulnerable DMA status path is reached through local DMAengine clients or device operations, not directly through network packets or physical insertion.\nAC:L - An attacker can repeatedly issue concurrent non-cyclic transfers and status queries, controlling the workload that produces both descriptor completion and stale traversal without relying on an uncontrollable condition.\nPR:L - Although the demonstrated dmatest configuration is normally root-controlled, userspace-accessible DMA clients are reasonable on affected embedded deployments and the provider performs no capability check. Following the highest-severity rule, a basic local user is sufficient.\nUI:N - Exploitation requires no action by another user after the attacker initiates the concurrent DMA operations.\nS:U - The UAF compromises the same host kernel security authority; it does not inherently cross a guest-host, sandbox, or IOMMU boundary.\nC:H - The descriptor and list links are accessed after dma_pool_free() and may contain recycled attacker-influenced contents; under the required UAF guidance this has high confidentiality impact.\nI:H - The kernel UAF permits freed descriptor storage to be reclaimed while stale references remain, making heap manipulation and code-execution primitives defensible under the supplied scoring guidance.\nA:H - Freed or poisoned list pointers can be dereferenced during iteration, causing a kernel oops or panic, and the race can be triggered repeatedly."
    }
  }
}