thp: use is_zero_pfn() only after pte_present() check

[cascardo/linux.git] / mm / huge_memory.c

diff --git a/mm/huge_memory.c b/mm/huge_memory.c
index 4b06b8d..bbac913 100644 (file)
--- a/mm/huge_memory.c
+++ b/mm/huge_memory.c
@@ -2206,7 +2206,8 @@ static int __collapse_huge_page_isolate(struct vm_area_struct *vma,
        for (_pte = pte; _pte < pte+HPAGE_PMD_NR;
             _pte++, address += PAGE_SIZE) {
                pte_t pteval = *_pte;
-               if (pte_none(pteval) || is_zero_pfn(pte_pfn(pteval))) {
+               if (pte_none(pteval) || (pte_present(pteval) &&
+                               is_zero_pfn(pte_pfn(pteval)))) {
                        if (!userfaultfd_armed(vma) &&
                            ++none_or_zero <= khugepaged_max_ptes_none)
                                continue;