mm: move page table sync declarations to linux/pgtable.h

{
  "id": "8c2788882893fa23fca9a3144b4919805dc095c77ab756a57333b7e9066715c7",
  "url": "https://osv.dev/vulnerability/CVE-2025-39844",
  "method": "structured",
  "payload": {
    "kind": "advisory",
    "title": "mm: move page table sync declarations to linux/pgtable.h",
    "summary": "In the Linux kernel, the following vulnerability has been resolved: mm: move page table sync declarations to linux/pgtable.h During our internal testing, we started observing intermittent boot failures when the machine uses 4-level paging and has 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 turns out that the kernel panics while initializing vmemmap (struct page array) when the vmemmap region spans two PGD entries, because the new PGD entry is only installed in init_mm.pgd, but not in the page tables of other tasks. And looking at __populate_section_memmap(): if (vmemmap_can_optimize(altmap, pgmap)) // does not sync top level page tables r = vmemmap_populate_compound_pages(pfn, start, end, nid, pgmap); else // sync top level page tables in x86 r = vmemmap_populate(start, end, nid, altmap); In the normal path, vmemmap_populate() in arch/x86/mm/init_64.c synchronizes the top level page table (See commit 9b861528a801 (\"x86-64, mem: Update all PGDs for direct mapping and vmemmap mapping changes\")) so that all tasks in the sys",
    "evidence": "osv:CVE-2025-39844",
    "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-2025-39844",
      "aliases": [
        "CVE-2025-39844"
      ],
      "affected": [
        {
          "ranges": [
            {
              "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
              "type": "GIT",
              "events": [
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                {
                  "fixed": "6797a8b3f71b2cb558b8771a03450dc3e004e453"
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                {
                  "fixed": "4f7537772011fad832f83d6848f8eab282545bef"
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                {
                  "fixed": "469f9d22751472b81eaaf8a27fcdb5a70741c342"
                },
                {
                  "fixed": "7cc183f2e67d19b03ee5c13a6664b8c6cc37ff9d"
                }
              ]
            }
          ],
          "database_specific": {
            "source": "https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2025-39844.json"
          }
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        {
          "ranges": [
            {
              "type": "ECOSYSTEM",
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                {
                  "fixed": "6.1.151"
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            {
              "type": "ECOSYSTEM",
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                {
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            {
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          ],
          "package": {
            "name": "Kernel",
            "ecosystem": "Linux"
          },
          "database_specific": {
            "source": "https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2025-39844.json"
          }
        }
      ],
      "modified": "2026-10-28T02:30:25.322373487Z",
      "provider": "osv",
      "references": [
        "https://cert-portal.siemens.com/productcert/html/ssa-032379.html",
        "https://git.kernel.org/stable/c/469f9d22751472b81eaaf8a27fcdb5a70741c342",
        "https://git.kernel.org/stable/c/4f7537772011fad832f83d6848f8eab282545bef",
        "https://git.kernel.org/stable/c/6797a8b3f71b2cb558b8771a03450dc3e004e453",
        "https://git.kernel.org/stable/c/732e62212f49d549c91071b4da7942ee3058f7a2",
        "https://git.kernel.org/stable/c/7cc183f2e67d19b03ee5c13a6664b8c6cc37ff9d",
        "https://git.kernel.org/stable/c/eceb44e1f94bd641b2a4e8c09b64c797c4eabc15",
        "https://lists.debian.org/debian-lts-announce/2025/10/msg00008.html",
        "https://github.com/CVEProject/cvelistV5/tree/main/cves/2025/39xxx/CVE-2025-39844.json",
        "https://nvd.nist.gov/vuln/detail/CVE-2025-39844",
        "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-2025-39844.json"
      }
    },
    "related_cves": [
      {
        "value": "CVE-2025-39844",
        "evidence": "/id"
      }
    ],
    "security_relevant": true,
    "severity_evidence": null
  },
  "source_id": "core-osv",
  "document_id": 492100,
  "published_at": "2025-09-19T15:26:18.471+00:00"
}