CVE-2026-93218

Full vulnerability record from the local CVENow database.

Description

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().

Severity

Not scored

CVSS score

Not available

Vulnerability status

Received

Source identifier

416baaa9-dc9f-4396-8d5f-8c081fb06d67

Published

2026-09-24 16:17:16.907000

Last modified

2026-10-19 10:17:12.730000

View original CVE JSON

{
  "id": "CVE-2026-93218",
  "sourceIdentifier": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
  "published": "2026-09-24T16:17:16.907",
  "lastModified": "2026-10-19T10:17:12.730",
  "vulnStatus": "Received",
  "cveTags": [],
  "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's pmd_trans_huge() check and the callee's pmd_trans_huge_lock()."
    }
  ],
  "affected": [
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "affectedData": [
        {
          "vendor": "Linux",
          "product": "Linux",
          "defaultStatus": "unaffected",
          "programFiles": [
            "mm/huge_memory.c"
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "versions": [
            {
              "version": "368076f52ebeecd33e10a9f80905d7508b6b6149",
              "lessThan": "5e3026bf736498115884d6c7bd0308ba29e0474c",
              "versionType": "git",
              "status": "affected"
            },
            {
              "version": "368076f52ebeecd33e10a9f80905d7508b6b6149",
              "lessThan": "ce579dcf730ce5ed8043a5eeea18a3e6706a97e5",
              "versionType": "git",
              "status": "affected"
            }
          ]
        },
        {
          "vendor": "Linux",
          "product": "Linux",
          "defaultStatus": "affected",
          "programFiles": [
            "mm/huge_memory.c"
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "versions": [
            {
              "version": "6.19",
              "status": "affected"
            },
            {
              "version": "0",
              "lessThan": "6.19",
              "versionType": "semver",
              "status": "unaffected"
            },
            {
              "version": "7.2.4",
              "lessThanOrEqual": "7.2.*",
              "versionType": "semver",
              "status": "unaffected"
            },
            {
              "version": "7.3",
              "lessThanOrEqual": "*",
              "versionType": "original_commit_for_fix",
              "status": "unaffected"
            }
          ]
        }
      ]
    }
  ],
  "metrics": {},
  "references": [
    {
      "url": "https://git.kernel.org/stable/c/5e3026bf736498115884d6c7bd0308ba29e0474c",
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
    },
    {
      "url": "https://git.kernel.org/stable/c/ce579dcf730ce5ed8043a5eeea18a3e6706a97e5",
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
    }
  ]
}