From 5bfea2d9b17f1034a68147a8b03b9789af5700f9 Mon Sep 17 00:00:00 2001 From: Fan Yang Date: Thu, 4 Jun 2020 18:22:07 +0800 Subject: mm: Fix mremap not considering huge pmd devmap The original code in mm/mremap.c checks huge pmd by: if (is_swap_pmd(*old_pmd) || pmd_trans_huge(*old_pmd)) { However, a DAX mapped nvdimm is mapped as huge page (by default) but it is not transparent huge page (_PAGE_PSE | PAGE_DEVMAP). This commit changes the condition to include the case. This addresses CVE-2020-10757. Fixes: 5c7fb56e5e3f ("mm, dax: dax-pmd vs thp-pmd vs hugetlbfs-pmd") Cc: Reported-by: Fan Yang Signed-off-by: Fan Yang Tested-by: Fan Yang Tested-by: Dan Williams Reviewed-by: Dan Williams Acked-by: Kirill A. Shutemov Signed-off-by: Linus Torvalds --- mm/mremap.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) (limited to 'mm/mremap.c') diff --git a/mm/mremap.c b/mm/mremap.c index 6aa6ea605068..57b1f999f789 100644 --- a/mm/mremap.c +++ b/mm/mremap.c @@ -266,7 +266,7 @@ unsigned long move_page_tables(struct vm_area_struct *vma, new_pmd = alloc_new_pmd(vma->vm_mm, vma, new_addr); if (!new_pmd) break; - if (is_swap_pmd(*old_pmd) || pmd_trans_huge(*old_pmd)) { + if (is_swap_pmd(*old_pmd) || pmd_trans_huge(*old_pmd) || pmd_devmap(*old_pmd)) { if (extent == HPAGE_PMD_SIZE) { bool moved; /* See comment in move_ptes() */ -- cgit v1.2.3