x86/fpu: Keep xfd_state in sync with MSR_IA32_XFD

{
  "id": "eef2139fddbc0a3a52f536df1995e4062f0d0c3f4ea7dfa1b4a75a3abea8d6a2",
  "url": "https://osv.dev/vulnerability/CVE-2024-35801",
  "method": "structured",
  "payload": {
    "kind": "advisory",
    "title": "x86/fpu: Keep xfd_state in sync with MSR_IA32_XFD",
    "summary": "In the Linux kernel, the following vulnerability has been resolved: x86/fpu: Keep xfd_state in sync with MSR_IA32_XFD Commit 672365477ae8 (\"x86/fpu: Update XFD state where required\") and commit 8bf26758ca96 (\"x86/fpu: Add XFD state to fpstate\") introduced a per CPU variable xfd_state to keep the MSR_IA32_XFD value cached, in order to avoid unnecessary writes to the MSR. On CPU hotplug MSR_IA32_XFD is reset to the init_fpstate.xfd, which wipes out any stale state. But the per CPU cached xfd value is not reset, which brings them out of sync. As a consequence a subsequent xfd_update_state() might fail to update the MSR which in turn can result in XRSTOR raising a #NM in kernel space, which crashes the kernel. To fix this, introduce xfd_set_state() to write xfd_state together with MSR_IA32_XFD, and use it in all places that set MSR_IA32_XFD.",
    "evidence": "osv:CVE-2024-35801",
    "products": [
      {
        "name": {
          "value": "Kernel",
          "evidence": "/affected/1/package/name"
        },
        "prerequisites": [],
        "fixed_versions": [
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            "value": "6.1.84",
            "evidence": "/affected/1/ranges"
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          {
            "value": "6.6.24",
            "evidence": "/affected/1/ranges"
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          {
            "value": "6.7.12",
            "evidence": "/affected/1/ranges"
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          {
            "value": "6.8.3",
            "evidence": "/affected/1/ranges"
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        "affected_versions": []
      }
    ],
    "severity": "high",
    "structured": {
      "id": "CVE-2024-35801",
      "aliases": [
        "CVE-2024-35801"
      ],
      "metrics": [
        {
          "type": "CVSS_V3",
          "score": "CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H"
        }
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              "type": "GIT",
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                {
                  "fixed": "21c7c00dae55cb0e3810d5f9506b58f68475d41d"
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                  "fixed": "1acbca933313aa866e39996904c9aca4d435c4cd"
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                  "fixed": "b61e3b7055ac6edee4be071c52f48c26472d2624"
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                {
                  "fixed": "10e4b5166df9ff7a2d5316138ca668b42d004422"
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              "type": "ECOSYSTEM",
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                  "introduced": "5.16.0"
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          "package": {
            "name": "Kernel",
            "ecosystem": "Linux"
          },
          "database_specific": {
            "source": "https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2024-35801.json"
          }
        }
      ],
      "modified": "2026-10-28T02:30:34.988438906Z",
      "provider": "osv",
      "references": [
        "https://git.kernel.org/stable/c/10e4b5166df9ff7a2d5316138ca668b42d004422",
        "https://git.kernel.org/stable/c/1acbca933313aa866e39996904c9aca4d435c4cd",
        "https://git.kernel.org/stable/c/21c7c00dae55cb0e3810d5f9506b58f68475d41d",
        "https://git.kernel.org/stable/c/92b0f04e937665bde5768f3fcc622dcce44413d8",
        "https://git.kernel.org/stable/c/b61e3b7055ac6edee4be071c52f48c26472d2624",
        "https://github.com/CVEProject/cvelistV5/tree/main/cves/2024/35xxx/CVE-2024-35801.json",
        "https://nvd.nist.gov/vuln/detail/CVE-2024-35801",
        "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/2024/35xxx/CVE-2024-35801.json"
      }
    },
    "related_cves": [
      {
        "value": "CVE-2024-35801",
        "evidence": "/id"
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    ],
    "security_relevant": true,
    "severity_evidence": "/severity/0/score"
  },
  "source_id": "core-osv",
  "document_id": 502183,
  "published_at": "2024-05-17T13:23:10.83+00:00"
}