| Message ID | 20250123160349.200154-1-agordeev@linux.ibm.com (mailing list archive) |
|---|---|
| State | New |
| Headers | show |
| Series | s390/mm: Add missing ctor/dtor on page table upgrade | expand |
On Thu, 23 Jan 2025 17:03:49 +0100 Alexander Gordeev <agordeev@linux.ibm.com> wrote: > 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. > > 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> > 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> > --- > The patch is against: > > git://git.kernel.org/pub/scm/linux/kernel/git/next/linux-next.git next-20250123 > git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm mm-stable > --- > arch/s390/mm/pgalloc.c | 3 +++ > 1 file changed, 3 insertions(+) > > diff --git a/arch/s390/mm/pgalloc.c b/arch/s390/mm/pgalloc.c > index a4e761902093..d33f55b7ee98 100644 > --- 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; Thanks, looks good, and nice catch. Reviewed-by: Gerald Schaefer <gerald.schaefer@linux.ibm.com>
diff --git a/arch/s390/mm/pgalloc.c b/arch/s390/mm/pgalloc.c index a4e761902093..d33f55b7ee98 100644 --- 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;
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. 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> 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> --- The patch is against: git://git.kernel.org/pub/scm/linux/kernel/git/next/linux-next.git next-20250123 git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm mm-stable --- arch/s390/mm/pgalloc.c | 3 +++ 1 file changed, 3 insertions(+)