accel/amdxdna: return early from a zero-length flush

{
  "id": "fc064feb06db8b6639fa525137cc612e5cc2ad1f167a7b764ceee280154182d5",
  "url": "https://osv.dev/vulnerability/CVE-2026-89978",
  "method": "structured",
  "payload": {
    "kind": "advisory",
    "title": "accel/amdxdna: return early from a zero-length flush",
    "summary": "In the Linux kernel, the following vulnerability has been resolved: accel/amdxdna: return early from a zero-length flush SYNC_BO does not constrain its size, so a request for zero bytes reaches drm_clflush_virt_range(), which ends with an unconditional clflushopt(end - 1). For an empty range that is the byte before the mapping, and abo->mem.kva comes from vmap(), so the access lands in the guard page below the vmalloc area and faults: BUG: unable to handle page fault for address: ffffd16fbbc70fff #PF: supervisor read access in kernel mode Oops: Oops: 0000 [#1] SMP NOPTI CPU: 7 UID: 1000 Comm: sync_bo_probe RIP: 0010:drm_clflush_virt_range+0x3c/0x70 Call Trace: amdxdna_drm_sync_bo_ioctl+0x124/0x430 [amdxdna] drm_ioctl+0x301/0x4c0 __x64_sys_ioctl+0x115/0x2f0 do_syscall_64+0xa6/0x3d0 Any process that can open the render node can do this. Reproduced 3 of 3 times on a Strix Point NPU (1022:17f0), by calling SYNC_BO with size 0 on an AMDXDNA_BO_SHARE object. The import arm takes the same request but flushes the whole scatterlist, so it survives it. Nothing needs flushing for an empty range, so answer before choosing a path.",
    "evidence": "osv:CVE-2026-89978",
    "products": [
      {
        "name": {
          "value": "Kernel",
          "evidence": "/affected/1/package/name"
        },
        "prerequisites": [],
        "fixed_versions": [
          {
            "value": "6.18.52",
            "evidence": "/affected/1/ranges"
          },
          {
            "value": "7.2.5",
            "evidence": "/affected/1/ranges"
          }
        ],
        "affected_versions": []
      }
    ],
    "severity": "unknown",
    "structured": {
      "id": "CVE-2026-89978",
      "aliases": [
        "CVE-2026-89978"
      ],
      "affected": [
        {
          "ranges": [
            {
              "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
              "type": "GIT",
              "events": [
                {
                  "introduced": "e252e3f3488a49267e08ea7d972ac5ba3f2f1763"
                },
                {
                  "fixed": "45962da5821d0a691f638ccb13842889156d8969"
                },
                {
                  "fixed": "f00def884a831dc49eb659dac2dd09dbfd21e67f"
                },
                {
                  "fixed": "dc14753664240cedf669623b27ae9922b0618b25"
                }
              ]
            }
          ],
          "database_specific": {
            "source": "https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2026-89978.json"
          }
        },
        {
          "ranges": [
            {
              "type": "ECOSYSTEM",
              "events": [
                {
                  "introduced": "6.17.0"
                },
                {
                  "fixed": "6.18.52"
                }
              ]
            },
            {
              "type": "ECOSYSTEM",
              "events": [
                {
                  "introduced": "6.19.0"
                },
                {
                  "fixed": "7.2.5"
                }
              ]
            }
          ],
          "package": {
            "name": "Kernel",
            "ecosystem": "Linux"
          },
          "database_specific": {
            "source": "https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2026-89978.json"
          }
        }
      ],
      "modified": "2026-10-28T02:30:50.169676392Z",
      "provider": "osv",
      "references": [
        "https://git.kernel.org/stable/c/45962da5821d0a691f638ccb13842889156d8969",
        "https://git.kernel.org/stable/c/dc14753664240cedf669623b27ae9922b0618b25",
        "https://git.kernel.org/stable/c/f00def884a831dc49eb659dac2dd09dbfd21e67f",
        "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/89xxx/CVE-2026-89978.json",
        "https://nvd.nist.gov/vuln/detail/CVE-2026-89978",
        "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/2026/89xxx/CVE-2026-89978.json"
      }
    },
    "related_cves": [
      {
        "value": "CVE-2026-89978",
        "evidence": "/id"
      }
    ],
    "security_relevant": true,
    "severity_evidence": null
  },
  "source_id": "core-osv",
  "document_id": 518617,
  "published_at": "2026-09-16T10:32:55.928+00:00"
}