This is a note to let you know that I've just added the patch titled
mm/migration: fix potential pte_unmap on an not mapped pte
to the 5.18-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary
The filename of the patch is:
mm-migration-fix-potential-pte_unmap-on-an-not-mappe.patch
and it can be found in the queue-5.18 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
commit 032e8dad266ef0b59b371edc82e23af44e61b3bf
Author: Miaohe Lin <linmiaohe@xxxxxxxxxx>
Date: Mon May 30 19:30:16 2022 +0800
mm/migration: fix potential pte_unmap on an not mapped pte
[ Upstream commit ad1ac596e8a8c4b06715dfbd89853eb73c9886b2 ]
__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@xxxxxxxxxx
Fixes: 30dad30922cc ("mm: migration: add migrate_entry_wait_huge()")
Signed-off-by: Miaohe Lin <linmiaohe@xxxxxxxxxx>
Suggested-by: David Hildenbrand <david@xxxxxxxxxx>
Reviewed-by: David Hildenbrand <david@xxxxxxxxxx>
Cc: Alistair Popple <apopple@xxxxxxxxxx>
Cc: Christoph Hellwig <hch@xxxxxx>
Cc: Christoph Lameter <cl@xxxxxxxxx>
Cc: David Howells <dhowells@xxxxxxxxxx>
Cc: Huang Ying <ying.huang@xxxxxxxxx>
Cc: kernel test robot <lkp@xxxxxxxxx>
Cc: Mike Kravetz <mike.kravetz@xxxxxxxxxx>
Cc: Muchun Song <songmuchun@xxxxxxxxxxxxx>
Cc: Oscar Salvador <osalvador@xxxxxxx>
Cc: Peter Xu <peterx@xxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>
diff --git a/include/linux/swapops.h b/include/linux/swapops.h
index d356ab4047f7..f99f0bd85724 100644
--- a/include/linux/swapops.h
+++ b/include/linux/swapops.h
@@ -216,8 +216,10 @@ 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)
{
@@ -238,8 +240,10 @@ 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;
diff --git a/mm/hugetlb.c b/mm/hugetlb.c
index 0090d7f98dee..19063dbed332 100644
--- a/mm/hugetlb.c
+++ b/mm/hugetlb.c
@@ -5602,7 +5602,7 @@ 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 |
@@ -6725,7 +6725,7 @@ follow_huge_pmd(struct mm_struct *mm, unsigned long address,
} 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;
}
/*
diff --git a/mm/migrate.c b/mm/migrate.c
index 796502d0eeb9..5aba3fb612d4 100644
--- a/mm/migrate.c
+++ b/mm/migrate.c
@@ -309,13 +309,28 @@ 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)
{
