mm: don't schedule deferred kernel page table freeing while booting

{
  "id": "e650f60a312e3cef571686488ebdf4bb965ab628d53ff6fa9b0281825ae8fc05",
  "url": "https://www.cve.org/CVERecord?id=CVE-2026-99093",
  "method": "structured",
  "payload": {
    "kind": "advisory",
    "title": "mm: don't schedule deferred kernel page table freeing while booting",
    "summary": "In the Linux kernel, the following vulnerability has been resolved: mm: don't schedule deferred kernel page table freeing while booting Booting with a boot-time function tracer and a filter, for example ftrace=function ftrace_filter=pud_free_pmd_page panics on 7.3-rc4 as soon as the tracer starts: [ 23.531178] Starting tracer 'function' [ 23.675800] Oops: general protection fault, probably for non-canonical address 0xdffffc0000000038: 0000 [#1] SMP KASAN NOPTI [ 23.819917] KASAN: null-ptr-deref in range [0x00000000000001c0-0x00000000000001c7] [ 23.964025] CPU: 0 UID: 0 PID: 0 Comm: swapper Not tainted 7.3.0-rc4-fe2ec83746e5-with-fixes-v2+ #195 PREEMPT(undef) [ 24.252248] RIP: 0010:__queue_work+0xab/0xf00 [ 25.981629] Call Trace: [ 26.125727] [ 26.413912] ? pagetable_free_kernel+0x20/0x120 [ 26.990283] queue_work_on+0x97/0xf0 [ 27.134382] __cpa_collapse_large_pages+0x501/0x6f0 [ 27.566662] cpa_flush+0x394/0x620 [ 27.998953] change_page_attr_set_clr+0x321/0x4a0 [ 29.151729] set_memory_rox+0xa2/0xf0 [ 29.584018] create_trampoline+0x431/0x6f0 ... [ 44.343347] Kernel panic - not syncing: Attempted to kill the idle task! The boot-time tracer is started from early_trace_init(), which runs before workqueue_init_early(). Making its trampoline read-only splits a large page, and CPA collapses it again right away. The split table has been a kernel page table since commit 9e4a3ec3411b (\"x86/mm/pat: Allocate split page tables as kernel page tables\"), so the collapse frees it through pageta",
    "evidence": "cve:CVE-2026-99093",
    "products": [
      {
        "name": {
          "value": "Linux",
          "evidence": "/containers/cna/affected/0/product"
        },
        "prerequisites": [],
        "fixed_versions": [],
        "affected_versions": []
      },
      {
        "name": {
          "value": "Linux",
          "evidence": "/containers/cna/affected/1/product"
        },
        "prerequisites": [],
        "fixed_versions": [],
        "affected_versions": []
      }
    ],
    "severity": "unknown",
    "structured": {
      "id": "CVE-2026-99093",
      "aliases": [
        "CVE-2026-99093"
      ],
      "metrics": [],
      "affected": [
        {
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "product": "Linux",
          "versions": [
            {
              "status": "affected",
              "version": "84e0cd79d57f06b872154eb5d8f610584133f260",
              "lessThan": "7a25ca170c12a9328f6fcf4410713beb516b01c0",
              "versionType": "git"
            },
            {
              "status": "affected",
              "version": "922873cf4fc34124215070a8ad391bf831538bb9",
              "lessThan": "df6c704a08bc0925d5db047b0a6221f962bda4d9",
              "versionType": "git"
            },
            {
              "status": "affected",
              "version": "9e4a3ec3411bb6bb59e3c1f29b75609f1e87aac4",
              "lessThan": "2fb552b0bee70c24c092720028ab4620f5eb2646",
              "versionType": "git"
            }
          ],
          "programFiles": [
            "mm/pgtable-generic.c"
          ],
          "defaultStatus": "unaffected"
        },
        {
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "product": "Linux",
          "versions": [
            {
              "status": "affected",
              "version": "6.18.53",
              "lessThan": "6.18.57",
              "versionType": "semver"
            },
            {
              "status": "affected",
              "version": "7.2.7",
              "lessThan": "7.2.11",
              "versionType": "semver"
            }
          ],
          "programFiles": [
            "mm/pgtable-generic.c"
          ],
          "defaultStatus": "unaffected"
        }
      ],
      "modified": "2026-10-26T14:52:01.450Z",
      "provider": "cve",
      "references": [
        "https://git.kernel.org/stable/c/7a25ca170c12a9328f6fcf4410713beb516b01c0",
        "https://git.kernel.org/stable/c/df6c704a08bc0925d5db047b0a6221f962bda4d9",
        "https://git.kernel.org/stable/c/2fb552b0bee70c24c092720028ab4620f5eb2646"
      ],
      "provider_metadata": {
        "cna": {
          "orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
          "shortName": "Linux",
          "dateUpdated": "2026-10-26T14:52:01.450Z"
        }
      }
    },
    "related_cves": [
      {
        "value": "CVE-2026-99093",
        "evidence": "/cveMetadata/cveId"
      }
    ],
    "security_relevant": true,
    "severity_evidence": null
  },
  "source_id": "core-cve",
  "document_id": 311610,
  "published_at": "2026-10-26T14:52:01.45+00:00"
}