Re: [PATCH] arm64: mm: use ptep_clear() instead of pte_clear() in clear_flush()

Qi Zheng
2023-08-11T02:38:57Z

I wrote wrong Kefeng's email address before, correct it now.

On 2023/8/10 17:32, Qi Zheng wrote:
> From: Qi Zheng <zhengqi.arch@bytedance.com>
>
> In clear_flush(), the original pte may be a present entry, so we should
> use ptep_clear() to let page_table_check track the pte clearing operation,
> otherwise it may cause false positive in subsequent set_pte_at().
>
> Fixes: 42b2547137f5 ("arm64/mm: enable ARCH_SUPPORTS_PAGE_TABLE_CHECK")
> Signed-off-by: Qi Zheng <zhengqi.arch@bytedance.com>
> ---
> arch/arm64/mm/hugetlbpage.c | 2 +-
> 1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/arch/arm64/mm/hugetlbpage.c b/arch/arm64/mm/hugetlbpage.c
> index 21716c940682..9c52718ea750 100644
> --- a/arch/arm64/mm/hugetlbpage.c
> +++ b/arch/arm64/mm/hugetlbpage.c
> @@ -236,7 +236,7 @@ static void clear_flush(struct mm_struct *mm,
> unsigned long i, saddr = addr;
>
> for (i = 0; i < ncontig; i++, addr += pgsize, ptep++)
> - pte_clear(mm, addr, ptep);
> + ptep_clear(mm, addr, ptep);
>
> flush_tlb_range(&vma, saddr, addr);
> }