check_pte() is the final validation step in page_vma_mapped_walk(). It reads pvmw->pte with ptep_get() to decide whether the entry maps the PFN range being walked. For hugetlb VMAs, that pointer refers to a hugetlb entry. On arches which provide their own huge_ptep_get() to dereference a huge pte pointer, accessing via ptep_get() would cause pte_pfn(), pte_present() etc to misbehave. It is not clear whether this has a trivially visible effect to userspace. Use huge_ptep_get() to dereference a huge pte pointer. Fixes: ace71a19cec5 ("mm: introduce page_vma_mapped_walk()") Cc: stable@vger.kernel.org Acked-by: David Hildenbrand (Arm) Reviewed-by: Muchun Song Signed-off-by: Dev Jain --- mm/page_vma_mapped.c | 8 +++++++- 1 file changed, 7 insertions(+), 1 deletion(-) diff --git a/mm/page_vma_mapped.c b/mm/page_vma_mapped.c index 2ccbabfb2cc17..18e1d341f463c 100644 --- a/mm/page_vma_mapped.c +++ b/mm/page_vma_mapped.c @@ -107,7 +107,13 @@ static bool map_pte(struct page_vma_mapped_walk *pvmw, pmd_t *pmdvalp, static bool check_pte(struct page_vma_mapped_walk *pvmw, unsigned long pte_nr) { unsigned long pfn; - pte_t ptent = ptep_get(pvmw->pte); + pte_t ptent; + + if (is_vm_hugetlb_page(pvmw->vma)) + ptent = huge_ptep_get(pvmw->vma->vm_mm, pvmw->address, + pvmw->pte); + else + ptent = ptep_get(pvmw->pte); if (pvmw->flags & PVMW_MIGRATION) { const softleaf_t entry = softleaf_from_pte(ptent); -- 2.43.0