s390/mm: add missing ctor/dtor on page table upgrade

Commit 78966b550289 ("s390: pgtable: add statistics for PUD and P4D level
page table") misses the call to pagetable_p4d_ctor() against a newly
allocated P4D table in crst_table_upgrade();

Commit 68c601de75d8 ("mm: introduce ctor/dtor at PGD level") misses the
call to pagetable_pgd_ctor() against a newly allocated PGD and the call to
pagetable_dtor() against a newly allocated P4D that is about to be freed
on crst_table_upgrade() PGD upgrade fail path.

The missed constructors and destructor break (at least) the page table
accounting when a process memory space is upgraded.

Link: https://lkml.kernel.org/r/20250123160349.200154-1-agordeev@linux.ibm.com
Fixes: 78966b550289 ("s390: pgtable: add statistics for PUD and P4D level page table")
Fixes: 68c601de75d8 ("mm: introduce ctor/dtor at PGD level")
Signed-off-by: Alexander Gordeev <agordeev@linux.ibm.com>
Reported-by: Heiko Carstens <hca@linux.ibm.com>
Closes: https://lore.kernel.org/all/20250122074954.8685-A-hca@linux.ibm.com/
Suggested-by: Heiko Carstens <hca@linux.ibm.com>
Reviewed-by: Gerald Schaefer <gerald.schaefer@linux.ibm.com>
Acked-by: Qi Zheng <zhengqi.arch@bytedance.com>
Reviewed-by: Kevin Brodsky <kevin.brodsky@arm.com>
Cc: Heiko Carstens <hca@linux.ibm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

diff --git a/arch/s390/mm/pgalloc.c b/arch/s390/mm/pgalloc.c
index a4e761902093181f87736e6200bb6d178ba09240..d33f55b7ee981f144e49d826028dc461244b4b5f 100644 (file)
--- a/arch/s390/mm/pgalloc.c
+++ b/arch/s390/mm/pgalloc.c
@@ -88,12 +88,14 @@ int crst_table_upgrade(struct mm_struct *mm, unsigned long end)
                if (unlikely(!p4d))
                        goto err_p4d;
                crst_table_init(p4d, _REGION2_ENTRY_EMPTY);
+               pagetable_p4d_ctor(virt_to_ptdesc(p4d));
        }
        if (end > _REGION1_SIZE) {
                pgd = crst_table_alloc(mm);
                if (unlikely(!pgd))
                        goto err_pgd;
                crst_table_init(pgd, _REGION1_ENTRY_EMPTY);
+               pagetable_pgd_ctor(virt_to_ptdesc(pgd));
        }
 
        spin_lock_bh(&mm->page_table_lock);
@@ -130,6 +132,7 @@ int crst_table_upgrade(struct mm_struct *mm, unsigned long end)
        return 0;
 
 err_pgd:
+       pagetable_dtor(virt_to_ptdesc(p4d));
        crst_table_free(mm, p4d);
 err_p4d:
        return -ENOMEM;