[PATCH v2 2/4] powerpc/mm/radix: Free PUD table when freeing pagetable

Michael Ellerman mpe at ellerman.id.au
Wed Jul 8 12:12:45 AEST 2020


"Aneesh Kumar K.V" <aneesh.kumar at linux.ibm.com> writes:
> From: Bharata B Rao <bharata at linux.ibm.com>
>
> remove_pagetable() isn't freeing PUD table. This causes memory
> leak during memory unplug. Fix this.

Fixes: ??

cheers

> Signed-off-by: Bharata B Rao <bharata at linux.ibm.com>
> Signed-off-by: Aneesh Kumar K.V <aneesh.kumar at linux.ibm.com>
> ---
>  arch/powerpc/mm/book3s64/radix_pgtable.c | 16 ++++++++++++++++
>  1 file changed, 16 insertions(+)
>
> diff --git a/arch/powerpc/mm/book3s64/radix_pgtable.c b/arch/powerpc/mm/book3s64/radix_pgtable.c
> index 80be96d3018f..af57604f295f 100644
> --- a/arch/powerpc/mm/book3s64/radix_pgtable.c
> +++ b/arch/powerpc/mm/book3s64/radix_pgtable.c
> @@ -708,6 +708,21 @@ static void free_pmd_table(pmd_t *pmd_start, pud_t *pud)
>  	pud_clear(pud);
>  }
>  
> +static void free_pud_table(pud_t *pud_start, p4d_t *p4d)
> +{
> +	pud_t *pud;
> +	int i;
> +
> +	for (i = 0; i < PTRS_PER_PUD; i++) {
> +		pud = pud_start + i;
> +		if (!pud_none(*pud))
> +			return;
> +	}
> +
> +	pud_free(&init_mm, pud_start);
> +	p4d_clear(p4d);
> +}
> +
>  struct change_mapping_params {
>  	pte_t *pte;
>  	unsigned long start;
> @@ -882,6 +897,7 @@ static void __meminit remove_pagetable(unsigned long start, unsigned long end)
>  
>  		pud_base = (pud_t *)p4d_page_vaddr(*p4d);
>  		remove_pud_table(pud_base, addr, next);
> +		free_pud_table(pud_base, p4d);
>  	}
>  
>  	spin_unlock(&init_mm.page_table_lock);
> -- 
> 2.26.2


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