x86/mm/64: define ARCH_PAGE_TABLE_SYNC_MASK and arch_sync_kernel_mappings()

{
  "id": "2f4684c98bd0f31380497a02897670a9c128a7b3c5ae1fb1007734de4035ca9e",
  "url": "https://osv.dev/vulnerability/CVE-2025-39845",
  "method": "structured",
  "payload": {
    "kind": "advisory",
    "title": "x86/mm/64: define ARCH_PAGE_TABLE_SYNC_MASK and arch_sync_kernel_mappings()",
    "summary": "In the Linux kernel, the following vulnerability has been resolved: x86/mm/64: define ARCH_PAGE_TABLE_SYNC_MASK and arch_sync_kernel_mappings() Define ARCH_PAGE_TABLE_SYNC_MASK and arch_sync_kernel_mappings() to ensure page tables are properly synchronized when calling p*d_populate_kernel(). For 5-level paging, synchronization is performed via pgd_populate_kernel(). In 4-level paging, pgd_populate() is a no-op, so synchronization is instead performed at the P4D level via p4d_populate_kernel(). This fixes intermittent boot failures on systems using 4-level paging and a large amount of persistent memory: BUG: unable to handle page fault for address: ffffe70000000034 #PF: supervisor write access in kernel mode #PF: error_code(0x0002) - not-present page PGD 0 P4D 0 Oops: 0002 [#1] SMP NOPTI RIP: 0010:__init_single_page+0x9/0x6d Call Trace: __init_zone_device_page+0x17/0x5d memmap_init_zone_device+0x154/0x1bb pagemap_range+0x2e0/0x40f memremap_pages+0x10b/0x2f0 devm_memremap_pages+0x1e/0x60 dev_dax_probe+0xce/0x2ec [device_dax] dax_bus_probe+0x6d/0xc9 [... snip ...] It also fixes a crash in vmemmap_set_pmd() caused by accessing vmemmap before sync_global_pgds() [1]: BUG: unable to handle page fault for address: ffffeb3ff1200000 #PF: supervisor write access in kernel mode #PF: error_code(0x0002) - not-present page PGD 0 P4D 0 Oops: Oops: 0002 [#1] PREEMPT SMP NOPTI Tainted: [W]=WARN RIP: 0010:vmemmap_set_pmd+0xff/0x230 vmemmap_populate_hugepages+0x176/0x180 vmemmap_populate+0x34/0x",
    "evidence": "osv:CVE-2025-39845",
    "products": [
      {
        "name": {
          "value": "Kernel",
          "evidence": "/affected/1/package/name"
        },
        "prerequisites": [],
        "fixed_versions": [
          {
            "value": "5.15.192",
            "evidence": "/affected/1/ranges"
          },
          {
            "value": "6.1.151",
            "evidence": "/affected/1/ranges"
          },
          {
            "value": "6.6.105",
            "evidence": "/affected/1/ranges"
          },
          {
            "value": "6.12.46",
            "evidence": "/affected/1/ranges"
          },
          {
            "value": "6.16.6",
            "evidence": "/affected/1/ranges"
          }
        ],
        "affected_versions": []
      }
    ],
    "severity": "unknown",
    "structured": {
      "id": "CVE-2025-39845",
      "aliases": [
        "CVE-2025-39845"
      ],
      "affected": [
        {
          "ranges": [
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              "type": "GIT",
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                  "fixed": "744ff519c72de31344a627eaf9b24e9595aae554"
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                {
                  "fixed": "5f761d40ee95d2624f839c90ebeef2d5c55007f5"
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                  "fixed": "26ff568f390a531d1bd792e49f1a401849921960"
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                  "fixed": "b7f4051dd3388edd30e9a6077c05c486aa31e0d4"
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                  "fixed": "6bf9473727569e8283c1e2445c7ac42cf4fc9fa9"
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                {
                  "fixed": "6659d027998083fbb6d42a165b0c90dc2e8ba989"
                }
              ]
            }
          ],
          "database_specific": {
            "source": "https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2025-39845.json"
          }
        },
        {
          "ranges": [
            {
              "type": "ECOSYSTEM",
              "events": [
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                  "introduced": "5.13.0"
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                  "fixed": "5.15.192"
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                  "introduced": "6.2.0"
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                {
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                  "introduced": "6.7.0"
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                {
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              "type": "ECOSYSTEM",
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          "package": {
            "name": "Kernel",
            "ecosystem": "Linux"
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          "database_specific": {
            "source": "https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2025-39845.json"
          }
        }
      ],
      "modified": "2026-10-28T02:30:25.502890127Z",
      "provider": "osv",
      "references": [
        "https://cert-portal.siemens.com/productcert/html/ssa-019113.html",
        "https://cert-portal.siemens.com/productcert/html/ssa-032379.html",
        "https://cert-portal.siemens.com/productcert/html/ssa-457936.html",
        "https://git.kernel.org/stable/c/26ff568f390a531d1bd792e49f1a401849921960",
        "https://git.kernel.org/stable/c/5f761d40ee95d2624f839c90ebeef2d5c55007f5",
        "https://git.kernel.org/stable/c/6659d027998083fbb6d42a165b0c90dc2e8ba989",
        "https://git.kernel.org/stable/c/6bf9473727569e8283c1e2445c7ac42cf4fc9fa9",
        "https://git.kernel.org/stable/c/744ff519c72de31344a627eaf9b24e9595aae554",
        "https://git.kernel.org/stable/c/b7f4051dd3388edd30e9a6077c05c486aa31e0d4",
        "https://lists.debian.org/debian-lts-announce/2025/10/msg00008.html",
        "https://github.com/CVEProject/cvelistV5/tree/main/cves/2025/39xxx/CVE-2025-39845.json",
        "https://nvd.nist.gov/vuln/detail/CVE-2025-39845",
        "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/2025/39xxx/CVE-2025-39845.json"
      }
    },
    "related_cves": [
      {
        "value": "CVE-2025-39845",
        "evidence": "/id"
      }
    ],
    "security_relevant": true,
    "severity_evidence": null
  },
  "source_id": "core-osv",
  "document_id": 492169,
  "published_at": "2025-09-19T15:26:19.225+00:00"
}