From ad1ac596e8a8c4b06715dfbd89853eb73c9886b2 Mon Sep 17 00:00:00 2001 From: Miaohe Lin Date: Mon, 30 May 2022 19:30:16 +0800 Subject: mm/migration: fix potential pte_unmap on an not mapped pte __migration_entry_wait and migration_entry_wait_on_locked assume pte is always mapped from caller. But this is not the case when it's called from migration_entry_wait_huge and follow_huge_pmd. Add a hugetlbfs variant that calls hugetlb_migration_entry_wait(ptep == NULL) to fix this issue. Link: https://lkml.kernel.org/r/20220530113016.16663-5-linmiaohe@huawei.com Fixes: 30dad30922cc ("mm: migration: add migrate_entry_wait_huge()") Signed-off-by: Miaohe Lin Suggested-by: David Hildenbrand Reviewed-by: David Hildenbrand Cc: Alistair Popple Cc: Christoph Hellwig Cc: Christoph Lameter Cc: David Howells Cc: Huang Ying Cc: kernel test robot Cc: Mike Kravetz Cc: Muchun Song Cc: Oscar Salvador Cc: Peter Xu Signed-off-by: Andrew Morton --- mm/migrate.c | 23 +++++++++++++++++++---- 1 file changed, 19 insertions(+), 4 deletions(-) (limited to 'mm/migrate.c') diff --git a/mm/migrate.c b/mm/migrate.c index 1d036dec1328..7934eebf1689 100644 --- a/mm/migrate.c +++ b/mm/migrate.c @@ -315,13 +315,28 @@ void migration_entry_wait(struct mm_struct *mm, pmd_t *pmd, __migration_entry_wait(mm, ptep, ptl); } -void migration_entry_wait_huge(struct vm_area_struct *vma, - struct mm_struct *mm, pte_t *pte) +#ifdef CONFIG_HUGETLB_PAGE +void __migration_entry_wait_huge(pte_t *ptep, spinlock_t *ptl) { - spinlock_t *ptl = huge_pte_lockptr(hstate_vma(vma), mm, pte); - __migration_entry_wait(mm, pte, ptl); + pte_t pte; + + spin_lock(ptl); + pte = huge_ptep_get(ptep); + + if (unlikely(!is_hugetlb_entry_migration(pte))) + spin_unlock(ptl); + else + migration_entry_wait_on_locked(pte_to_swp_entry(pte), NULL, ptl); } +void migration_entry_wait_huge(struct vm_area_struct *vma, pte_t *pte) +{ + spinlock_t *ptl = huge_pte_lockptr(hstate_vma(vma), vma->vm_mm, pte); + + __migration_entry_wait_huge(pte, ptl); +} +#endif + #ifdef CONFIG_ARCH_ENABLE_THP_MIGRATION void pmd_migration_entry_wait(struct mm_struct *mm, pmd_t *pmd) { -- cgit v1.2.3