Commit 8ee53820edfd ("thp: mmu_notifier_test_young") introduced
mmu_notifier_test_young(), but we should pass the address need to test.
In xxx_scan_pmd(), the actual iteration address is "_address" not
"address". We seem to misuse the variable on the very beginning.

Change it to the right one.

Fixes: 8ee53820edfd ("thp: mmu_notifier_test_young")
Signed-off-by: Wei Yang <richard.weiyang@gmail.com>
Cc: David Hildenbrand <david@redhat.com>
Cc: Lorenzo Stoakes <lorenzo.stoakes@oracle.com>
Cc: Zi Yan <ziy@nvidia.com>
Cc: Baolin Wang <baolin.wang@linux.alibaba.com>
Cc: Liam R. Howlett <Liam.Howlett@oracle.com>
Cc: Nico Pache <npache@redhat.com>
Cc: Ryan Roberts <ryan.roberts@arm.com>
Cc: Dev Jain <dev.jain@arm.com>
Cc: Barry Song <baohua@kernel.org>
CC: <stable@vger.kernel.org>

---
The original commit 8ee53820edfd is at 2011.
Then the code is moved to khugepaged.c in commit b46e756f5e470 ("thp:
extract khugepaged from mm/huge_memory.c") in 2022.
---
 mm/khugepaged.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/mm/khugepaged.c b/mm/khugepaged.c
index 24e18a7f8a93..b000942250d1 100644
--- a/mm/khugepaged.c
+++ b/mm/khugepaged.c
@@ -1418,7 +1418,7 @@ static int hpage_collapse_scan_pmd(struct mm_struct *mm,
 		if (cc->is_khugepaged &&
 		    (pte_young(pteval) || folio_test_young(folio) ||
 		     folio_test_referenced(folio) || mmu_notifier_test_young(vma->vm_mm,
-								     address)))
+								     _address)))
 			referenced++;
 	}
 	if (!writable) {
-- 
2.34.1