Sebastian Ott and Gerald Schaefer reported random crashes on s390.
It was bisected to my THP refcounting patchset.
The problem is that pmdp_invalidated() called with wrong virtual
address. It got offset up by HPAGE_PMD_SIZE by loop over ptes.
The solution is to introduce new variable to be used in loop and don't
touch 'haddr'.
Signed-off-by: Kirill A. Shutemov <kirill.shutemov@xxxxxxxxxxxxxxx>
Reported-by: Gerald Schaefer <gerald.schaefer@xxxxxxxxxx>
Reported-by Sebastian Ott <sebott@xxxxxxxxxxxxxxxxxx>
---
mm/huge_memory.c | 9 +++++----
1 file changed, 5 insertions(+), 4 deletions(-)
diff --git a/mm/huge_memory.c b/mm/huge_memory.c
index 1c317b85ea7d..e10a4fee88d2 100644
--- a/mm/huge_memory.c
+++ b/mm/huge_memory.c
@@ -2836,6 +2836,7 @@ static void __split_huge_pmd_locked(struct vm_area_struct *vma, pmd_t *pmd,
pgtable_t pgtable;
pmd_t _pmd;
bool young, write, dirty;
+ unsigned long addr;
int i;
VM_BUG_ON(haddr & ~HPAGE_PMD_MASK);
@@ -2865,7 +2866,7 @@ static void __split_huge_pmd_locked(struct vm_area_struct *vma, pmd_t *pmd,
pgtable = pgtable_trans_huge_withdraw(mm, pmd);
pmd_populate(mm, &_pmd, pgtable);
- for (i = 0; i < HPAGE_PMD_NR; i++, haddr += PAGE_SIZE) {
+ for (i = 0, addr = haddr; i < HPAGE_PMD_NR; i++, addr += PAGE_SIZE) {
pte_t entry, *pte;
/*
* Note that NUMA hinting access restrictions are not
@@ -2886,9 +2887,9 @@ static void __split_huge_pmd_locked(struct vm_area_struct *vma, pmd_t *pmd,
}
if (dirty)
SetPageDirty(page + i);
- pte = pte_offset_map(&_pmd, haddr);
+ pte = pte_offset_map(&_pmd, addr);
BUG_ON(!pte_none(*pte));
- set_pte_at(mm, haddr, pte, entry);
+ set_pte_at(mm, addr, pte, entry);
atomic_inc(&page[i]._mapcount);
pte_unmap(pte);
}
@@ -2938,7 +2939,7 @@ static void __split_huge_pmd_locked(struct vm_area_struct *vma, pmd_t *pmd,
pmd_populate(mm, pmd, pgtable);
if (freeze) {
- for (i = 0; i < HPAGE_PMD_NR; i++, haddr += PAGE_SIZE) {
+ for (i = 0; i < HPAGE_PMD_NR; i++) {
page_remove_rmap(page + i, false);
put_page(page + i);
}
--
2.7.0
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