CVE-2026-93217

/// Technical description

In the Linux kernel, the following vulnerability has been resolved:

mm/madvise: skip device-private PMDs in cold and pageout walks

madvise_cold_or_pageout_pte_range() takes pmd_trans_huge_lock(), whose

pmd_is_huge() check returns true for a device-private PMD. The subsequent

!pmd_present() branch has a VM_BUG_ON() asserting migration is the only

allowed non-present case; a device-private PMD trips it.

Skip device-private PMDs in that non-present branch and continue to

huge_unlock 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(MA

/// Remediation

Check the references section for vendor advisories, patches, and mitigation guidance. If immediate patching is not possible, review the CVSS vector to understand the attack surface and apply compensating controls such as network segmentation or access restrictions.

/// References