tracing: Fix WARN_ON in tracing_buffers_mmap_close for split VMAs

{
  "id": "9a42eb787136b511a65db26e79dad79b4a47b1702c2f2df69e514d1cc109850f",
  "url": "https://osv.dev/vulnerability/CVE-2025-68329",
  "method": "structured",
  "payload": {
    "kind": "advisory",
    "title": "tracing: Fix WARN_ON in tracing_buffers_mmap_close for split VMAs",
    "summary": "In the Linux kernel, the following vulnerability has been resolved: tracing: Fix WARN_ON in tracing_buffers_mmap_close for split VMAs When a VMA is split (e.g., by partial munmap or MAP_FIXED), the kernel calls vm_ops->close on each portion. For trace buffer mappings, this results in ring_buffer_unmap() being called multiple times while ring_buffer_map() was only called once. This causes ring_buffer_unmap() to return -ENODEV on subsequent calls because user_mapped is already 0, triggering a WARN_ON. Trace buffer mappings cannot support partial mappings because the ring buffer structure requires the complete buffer including the meta page. Fix this by adding a may_split callback that returns -EINVAL to prevent VMA splits entirely.",
    "evidence": "osv:CVE-2025-68329",
    "products": [
      {
        "name": {
          "value": "Kernel",
          "evidence": "/affected/1/package/name"
        },
        "prerequisites": [],
        "fixed_versions": [
          {
            "value": "6.12.61",
            "evidence": "/affected/1/ranges"
          },
          {
            "value": "6.17.11",
            "evidence": "/affected/1/ranges"
          }
        ],
        "affected_versions": []
      }
    ],
    "severity": "unknown",
    "structured": {
      "id": "CVE-2025-68329",
      "aliases": [
        "CVE-2025-68329"
      ],
      "affected": [
        {
          "ranges": [
            {
              "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
              "type": "GIT",
              "events": [
                {
                  "introduced": "cf9f0f7c4c5bb45e7bb270e48bab6f7837825a64"
                },
                {
                  "fixed": "922fdd0b755a84f9933b3ca195f60092b6bb88ee"
                },
                {
                  "fixed": "45053c12c45f0fb8ef6ab95118dd928d2fec0255"
                },
                {
                  "fixed": "b042fdf18e89a347177a49e795d8e5184778b5b6"
                }
              ]
            }
          ],
          "database_specific": {
            "source": "https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2025-68329.json"
          }
        },
        {
          "ranges": [
            {
              "type": "ECOSYSTEM",
              "events": [
                {
                  "introduced": "6.10.0"
                },
                {
                  "fixed": "6.12.61"
                }
              ]
            },
            {
              "type": "ECOSYSTEM",
              "events": [
                {
                  "introduced": "6.13.0"
                },
                {
                  "fixed": "6.17.11"
                }
              ]
            }
          ],
          "package": {
            "name": "Kernel",
            "ecosystem": "Linux"
          },
          "database_specific": {
            "source": "https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2025-68329.json"
          }
        }
      ],
      "modified": "2026-10-28T02:30:23.791571778Z",
      "provider": "osv",
      "references": [
        "https://git.kernel.org/stable/c/45053c12c45f0fb8ef6ab95118dd928d2fec0255",
        "https://git.kernel.org/stable/c/922fdd0b755a84f9933b3ca195f60092b6bb88ee",
        "https://git.kernel.org/stable/c/b042fdf18e89a347177a49e795d8e5184778b5b6",
        "https://github.com/CVEProject/cvelistV5/tree/main/cves/2025/68xxx/CVE-2025-68329.json",
        "https://nvd.nist.gov/vuln/detail/CVE-2025-68329",
        "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/2025/68xxx/CVE-2025-68329.json"
      }
    },
    "related_cves": [
      {
        "value": "CVE-2025-68329",
        "evidence": "/id"
      }
    ],
    "security_relevant": true,
    "severity_evidence": null
  },
  "source_id": "core-osv",
  "document_id": 490292,
  "published_at": "2025-12-22T16:12:23.133+00:00"
}