[PATCH v4 13/13] mm/debug_vm_pgtable: Avoid none pte in pte_clear_test

[Anshuman Khandual]

On 09/02/2020 05:16 PM, Aneesh Kumar K.V wrote:
> pte_clear_tests operate on an existing pte entry. Make sure that
> is not a none pte entry.
> 
> Signed-off-by: Aneesh Kumar K.V <aneesh.kumar at linux.ibm.com>
> ---
>  mm/debug_vm_pgtable.c | 7 ++++---
>  1 file changed, 4 insertions(+), 3 deletions(-)
> 
> diff --git a/mm/debug_vm_pgtable.c b/mm/debug_vm_pgtable.c
> index 9afa1354326b..c36530c69e33 100644
> --- a/mm/debug_vm_pgtable.c
> +++ b/mm/debug_vm_pgtable.c
> @@ -542,9 +542,10 @@ static void __init pgd_populate_tests(struct mm_struct *mm, pgd_t *pgdp,
>  #endif /* PAGETABLE_P4D_FOLDED */
>  
>  static void __init pte_clear_tests(struct mm_struct *mm, pte_t *ptep,
> -				   unsigned long vaddr)
> +				   unsigned long pfn, unsigned long vaddr,
> +				   pgprot_t prot)
>  {
> -	pte_t pte = ptep_get(ptep);
> +	pte_t pte = pfn_pte(pfn, prot);
>  
>  	pr_debug("Validating PTE clear\n");
>  	pte = __pte(pte_val(pte) | RANDOM_ORVALUE);
> @@ -1049,7 +1050,7 @@ static int __init debug_vm_pgtable(void)
>  
>  	ptl = pte_lockptr(mm, pmdp);
>  	spin_lock(ptl);
> -	pte_clear_tests(mm, ptep, vaddr);
> +	pte_clear_tests(mm, ptep, pte_aligned, vaddr, prot);
>  	pte_advanced_tests(mm, vma, ptep, pte_aligned, vaddr, prot);
>  	pte_unmap_unlock(ptep, ptl);
>  
> 

Reviewed-by: Anshuman Khandual <anshuman.khandual at arm.com>