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mm/migration: fix potential pte_unmap on an not mapped pte

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__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: 30dad30922 ("mm: migration: add migrate_entry_wait_huge()")
Signed-off-by: Miaohe Lin <linmiaohe@huawei.com>
Suggested-by: David Hildenbrand <david@redhat.com>
Reviewed-by: David Hildenbrand <david@redhat.com>
Cc: Alistair Popple <apopple@nvidia.com>
Cc: Christoph Hellwig <hch@lst.de>
Cc: Christoph Lameter <cl@linux.com>
Cc: David Howells <dhowells@redhat.com>
Cc: Huang Ying <ying.huang@intel.com>
Cc: kernel test robot <lkp@intel.com>
Cc: Mike Kravetz <mike.kravetz@oracle.com>
Cc: Muchun Song <songmuchun@bytedance.com>
Cc: Oscar Salvador <osalvador@suse.de>
Cc: Peter Xu <peterx@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
This commit is contained in:
Miaohe Lin 2022-05-30 19:30:16 +08:00 committed by akpm
parent 7ce82f4c3f
commit ad1ac596e8
3 changed files with 29 additions and 10 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

12
include/linux/swapops.h
View File

@ -244,8 +244,10 @@ extern void __migration_entry_wait(struct mm_struct *mm, pte_t *ptep,
spinlock_t *ptl);
extern void migration_entry_wait(struct mm_struct *mm, pmd_t *pmd,
unsigned long address);
extern void migration_entry_wait_huge(struct vm_area_struct *vma,
struct mm_struct *mm, pte_t *pte);
#ifdef CONFIG_HUGETLB_PAGE
extern void __migration_entry_wait_huge(pte_t *ptep, spinlock_t *ptl);
extern void migration_entry_wait_huge(struct vm_area_struct *vma, pte_t *pte);
#endif
#else
static inline swp_entry_t make_readable_migration_entry(pgoff_t offset)
{
@ -271,8 +273,10 @@ static inline void __migration_entry_wait(struct mm_struct *mm, pte_t *ptep,
spinlock_t *ptl) { }
static inline void migration_entry_wait(struct mm_struct *mm, pmd_t *pmd,
unsigned long address) { }
static inline void migration_entry_wait_huge(struct vm_area_struct *vma,
struct mm_struct *mm, pte_t *pte) { }
#ifdef CONFIG_HUGETLB_PAGE
static inline void __migration_entry_wait_huge(pte_t *ptep, spinlock_t *ptl) { }
static inline void migration_entry_wait_huge(struct vm_area_struct *vma, pte_t *pte) { }
#endif
static inline int is_writable_migration_entry(swp_entry_t entry)
{
return 0;

4
mm/hugetlb.c
View File

@ -5702,7 +5702,7 @@ vm_fault_t hugetlb_fault(struct mm_struct *mm, struct vm_area_struct *vma,
*/
entry = huge_ptep_get(ptep);
if (unlikely(is_hugetlb_entry_migration(entry))) {
migration_entry_wait_huge(vma, mm, ptep);
migration_entry_wait_huge(vma, ptep);
return 0;
} else if (unlikely(is_hugetlb_entry_hwpoisoned(entry)))
return VM_FAULT_HWPOISON_LARGE |
@ -6927,7 +6927,7 @@ retry:
} else {
if (is_hugetlb_entry_migration(pte)) {
spin_unlock(ptl);
__migration_entry_wait(mm, (pte_t *)pmd, ptl);
__migration_entry_wait_huge((pte_t *)pmd, ptl);
goto retry;
}
/*

23
mm/migrate.c
View File

@ -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)
{