From 4286f14748c13de42c1c4ab77a92fdfb37e6e5ef Mon Sep 17 00:00:00 2001 From: Miaohe Lin Date: Mon, 4 Jul 2022 21:21:47 +0800 Subject: [PATCH] mm/huge_memory: access vm_page_prot with READ_ONCE in remove_migration_pmd vma->vm_page_prot is read lockless from the rmap_walk, it may be updated concurrently. Using READ_ONCE to prevent the risk of reading intermediate values. Link: https://lkml.kernel.org/r/20220704132201.14611-3-linmiaohe@huawei.com Signed-off-by: Miaohe Lin Cc: Matthew Wilcox Cc: Muchun Song Cc: Yang Shi Cc: Zach O'Keefe Signed-off-by: Andrew Morton --- mm/huge_memory.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/mm/huge_memory.c b/mm/huge_memory.c index 627b98dfd51e..fb0011fe9128 100644 --- a/mm/huge_memory.c +++ b/mm/huge_memory.c @@ -3205,7 +3205,7 @@ void remove_migration_pmd(struct page_vma_mapped_walk *pvmw, struct page *new) entry = pmd_to_swp_entry(*pvmw->pmd); get_page(new); - pmde = pmd_mkold(mk_huge_pmd(new, vma->vm_page_prot)); + pmde = pmd_mkold(mk_huge_pmd(new, READ_ONCE(vma->vm_page_prot))); if (pmd_swp_soft_dirty(*pvmw->pmd)) pmde = pmd_mksoft_dirty(pmde); if (is_writable_migration_entry(entry)) -- 2.11.0