CVE-2026-93218
NONEDescription
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().
Affected routers (0)
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