iommufd: Take dma_resv lock before dma_buf_unpin() in release path

{
  "id": "608e6771f09277b056d74b1eedacbfd263870c17616a6d4572ee80748280edea",
  "url": "https://osv.dev/vulnerability/CVE-2026-80633",
  "method": "structured",
  "payload": {
    "kind": "advisory",
    "title": "iommufd: Take dma_resv lock before dma_buf_unpin() in release path",
    "summary": "In the Linux kernel, the following vulnerability has been resolved: iommufd: Take dma_resv lock before dma_buf_unpin() in release path dma_buf_unpin() requires the caller to hold the exporter's dma_resv lock: void dma_buf_unpin(struct dma_buf_attachment *attach) { ... dma_resv_assert_held(dmabuf->resv); ... } iopt_release_pages() calls dma_buf_unpin() without taking that lock, so every iommufd_ioas_destroy()/iommufd_ioas_unmap() that releases the last reference on a DMABUF-backed iopt_pages triggers a WARN. This was hit while running tools/testing/selftests/iommu/iommufd: WARNING: drivers/dma-buf/dma-buf.c:1137 at dma_buf_unpin+0x62/0x70 RIP: 0010:dma_buf_unpin+0x62/0x70 Call Trace: dma_buf_unpin+0x62/0x70 iopt_release_pages+0xe4/0x190 iopt_unmap_iova_range+0x1c7/0x290 iopt_unmap_all+0x1a/0x30 iommufd_ioas_destroy+0x1d/0x50 iommufd_fops_release+0x93/0x150 __fput+0xfc/0x2c0 __x64_sys_close+0x3d/0x80 do_syscall_64+0x65/0x180 Take the dma_resv lock around dma_buf_unpin() in iopt_release_pages(), matching the iopt_map_dmabuf() convention. dma_buf_detach() acquires the reservation lock internally, so it must remain outside the locked region.",
    "evidence": "osv:CVE-2026-80633",
    "products": [
      {
        "name": {
          "value": "Kernel",
          "evidence": "/affected/1/package/name"
        },
        "prerequisites": [],
        "fixed_versions": [
          {
            "value": "7.1.5",
            "evidence": "/affected/1/ranges"
          }
        ],
        "affected_versions": []
      }
    ],
    "severity": "high",
    "structured": {
      "id": "CVE-2026-80633",
      "aliases": [
        "CVE-2026-80633"
      ],
      "metrics": [
        {
          "type": "CVSS_V3",
          "score": "CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:H"
        }
      ],
      "affected": [
        {
          "ranges": [
            {
              "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
              "type": "GIT",
              "events": [
                {
                  "introduced": "8c5f9645c3893f0db679d9affe4fe4e665b990dd"
                },
                {
                  "fixed": "cc69d0332421fd2943b66dbe5e597bf4fd5af126"
                },
                {
                  "fixed": "e745cd2c749e557c14a15ac931761c3f58c24489"
                }
              ]
            }
          ],
          "database_specific": {
            "source": "https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2026-80633.json"
          }
        },
        {
          "ranges": [
            {
              "type": "ECOSYSTEM",
              "events": [
                {
                  "introduced": "7.1.0"
                },
                {
                  "fixed": "7.1.5"
                }
              ]
            }
          ],
          "package": {
            "name": "Kernel",
            "ecosystem": "Linux"
          },
          "database_specific": {
            "source": "https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2026-80633.json"
          }
        }
      ],
      "modified": "2026-10-28T02:30:51.093546329Z",
      "provider": "osv",
      "references": [
        "https://git.kernel.org/stable/c/cc69d0332421fd2943b66dbe5e597bf4fd5af126",
        "https://git.kernel.org/stable/c/e745cd2c749e557c14a15ac931761c3f58c24489",
        "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/80xxx/CVE-2026-80633.json",
        "https://nvd.nist.gov/vuln/detail/CVE-2026-80633",
        "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git"
      ],
      "provider_metadata": {
        "cna_assigner": "Linux",
        "osv_generated_from": "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/80xxx/CVE-2026-80633.json"
      }
    },
    "related_cves": [
      {
        "value": "CVE-2026-80633",
        "evidence": "/id"
      }
    ],
    "security_relevant": true,
    "severity_evidence": "/severity/0/score"
  },
  "source_id": "core-osv",
  "document_id": 519922,
  "published_at": "2026-08-28T06:48:48.372+00:00"
}