CVE-2026-93218 (GCVE-0-2026-93218)
Vulnerability from cvelistv5
Published
2026-09-24 15:10
Modified
2026-10-19 09:07
Severity ?
Summary
In the Linux kernel, the following vulnerability has been resolved: mm/huge_memory: skip device-private PMDs in madvise_free_huge_pmd madvise_free_pte_range() checks pmd_trans_huge(*pmd) unlocked, then madvise_free_huge_pmd() takes pmd_trans_huge_lock(). pmd_is_huge() returns true for a device-private PMD, so orig_pmd can be device-private and enter the !pmd_present() branch. Skip device-private PMDs in that non-present branch and continue to out before calling pmd_folio(). Downgrade the check to VM_WARN_ON_ONCE() so an unexpected PMD softleaf logs a warning rather than panicking. Drop the thp_migration_supported() guard: it expands to IS_ENABLED(CONFIG_ARCH_SUPPORTS_PMD_SOFTLEAF), and both pmd_is_migration_entry() and pmd_is_device_private_entry() already return false when that config is not selected, so the guard suppresses only the case where the warning would already be silent. Potential trigger: an HMM-based GPU driver races with madvise(MADV_FREE): migrate_vma_pages() flips the PMD to a device-private entry between the caller's pmd_trans_huge() check and the callee's pmd_trans_huge_lock().
References
Impacted products
Vendor Product Version
Linux Linux Version: 368076f52ebeecd33e10a9f80905d7508b6b6149
Version: 368076f52ebeecd33e10a9f80905d7508b6b6149
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{
  "containers": {
    "cna": {
      "affected": [
        {
          "defaultStatus": "unaffected",
          "product": "Linux",
          "programFiles": [
            "mm/huge_memory.c"
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "versions": [
            {
              "lessThan": "5e3026bf736498115884d6c7bd0308ba29e0474c",
              "status": "affected",
              "version": "368076f52ebeecd33e10a9f80905d7508b6b6149",
              "versionType": "git"
            },
            {
              "lessThan": "ce579dcf730ce5ed8043a5eeea18a3e6706a97e5",
              "status": "affected",
              "version": "368076f52ebeecd33e10a9f80905d7508b6b6149",
              "versionType": "git"
            }
          ]
        },
        {
          "defaultStatus": "affected",
          "product": "Linux",
          "programFiles": [
            "mm/huge_memory.c"
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "versions": [
            {
              "status": "affected",
              "version": "6.19"
            },
            {
              "lessThan": "6.19",
              "status": "unaffected",
              "version": "0",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "7.2.*",
              "status": "unaffected",
              "version": "7.2.4",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "*",
              "status": "unaffected",
              "version": "7.3",
              "versionType": "original_commit_for_fix"
            }
          ]
        }
      ],
      "cpeApplicability": [
        {
          "nodes": [
            {
              "cpeMatch": [
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "7.2.4",
                  "versionStartIncluding": "6.19",
                  "vulnerable": true
                },
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "7.3",
                  "versionStartIncluding": "6.19",
                  "vulnerable": true
                }
              ],
              "negate": false,
              "operator": "OR"
            }
          ]
        }
      ],
      "descriptions": [
        {
          "lang": "en",
          "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nmm/huge_memory: skip device-private PMDs in madvise_free_huge_pmd\n\nmadvise_free_pte_range() checks pmd_trans_huge(*pmd) unlocked, then\nmadvise_free_huge_pmd() takes pmd_trans_huge_lock().  pmd_is_huge()\nreturns true for a device-private PMD, so orig_pmd can be device-private\nand enter the !pmd_present() branch.\n\nSkip device-private PMDs in that non-present branch and continue to out\nbefore calling pmd_folio().  Downgrade the check to VM_WARN_ON_ONCE() so\nan unexpected PMD softleaf logs a warning rather than panicking.  Drop the\nthp_migration_supported() guard: it expands to\nIS_ENABLED(CONFIG_ARCH_SUPPORTS_PMD_SOFTLEAF), and both\npmd_is_migration_entry() and pmd_is_device_private_entry() already return\nfalse when that config is not selected, so the guard suppresses only the\ncase where the warning would already be silent.\n\nPotential trigger: an HMM-based GPU driver races with madvise(MADV_FREE):\nmigrate_vma_pages() flips the PMD to a device-private entry between the\ncaller\u0027s pmd_trans_huge() check and the callee\u0027s pmd_trans_huge_lock()."
        }
      ],
      "providerMetadata": {
        "dateUpdated": "2026-10-19T09:07:29.994Z",
        "orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
        "shortName": "Linux"
      },
      "references": [
        {
          "url": "https://git.kernel.org/stable/c/5e3026bf736498115884d6c7bd0308ba29e0474c"
        },
        {
          "url": "https://git.kernel.org/stable/c/ce579dcf730ce5ed8043a5eeea18a3e6706a97e5"
        }
      ],
      "title": "mm/huge_memory: skip device-private PMDs in madvise_free_huge_pmd",
      "x_generator": {
        "engine": "bippy-1.2.0"
      }
    }
  },
  "cveMetadata": {
    "assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
    "assignerShortName": "Linux",
    "cveId": "CVE-2026-93218",
    "datePublished": "2026-09-24T15:10:41.370Z",
    "dateReserved": "2026-09-17T16:02:15.094Z",
    "dateUpdated": "2026-10-19T09:07:29.994Z",
    "state": "PUBLISHED"
  },
  "dataType": "CVE_RECORD",
  "dataVersion": "5.2"
}


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