Re: [PATCH] selftests/mm: fix size truncation in pagemap_ioctl test

[Gregory Price]

On Mon, Sep 07, 2026 at 09:56:13PM +0800, Zenghui Yu wrote:
> From: "Zenghui Yu (Huawei)" <zenghui.yu@xxxxxxxxx>
> 
> On arm64 with 64K base pages, the huge page size is 512 MiB, and
> hpage_unit_tests() builds a 5 GiB range (10 * 512 MiB) for its tests.  This
> exceeds the range of the int size parameters of gethugepage(),
> wp_addr_range() and pagemap_ioctl().  The implicit truncation to 1 GiB
> makes gethugepage() allocate a too small buffer, while the callers keep
> operating on the original 5 GiB range, resulting in spurious failures or
> SIGSEGV.
> 
> Change those size parameters to size_t.
> 
> Fixes: 46fd75d4a3c9 ("selftests: mm: add pagemap ioctl tests")
> Assisted-by: GLM-5.3 OpenCode
> Signed-off-by: Zenghui Yu (Huawei) <zenghui.yu@xxxxxxxxx>

Reviewed-by: Gregory Price (Meta) <gourry@xxxxxxxxxx>

> ---
>  tools/testing/selftests/mm/pagemap_ioctl.c | 6 +++---
>  1 file changed, 3 insertions(+), 3 deletions(-)
> 
> diff --git a/tools/testing/selftests/mm/pagemap_ioctl.c b/tools/testing/selftests/mm/pagemap_ioctl.c
> index eadc7159ca5b..48cbea3a33c9 100644
> --- a/tools/testing/selftests/mm/pagemap_ioctl.c
> +++ b/tools/testing/selftests/mm/pagemap_ioctl.c
> @@ -44,7 +44,7 @@ const char *progname;
>  
>  #define LEN(region)	((region.end - region.start)/page_size)
>  
> -static long pagemap_ioctl(void *start, int len, void *vec, int vec_len, int flag,
> +static long pagemap_ioctl(void *start, size_t len, void *vec, int vec_len, int flag,
>  			  int max_pages, long required_mask, long anyof_mask, long excluded_mask,
>  			  long return_mask)
>  {
> @@ -152,7 +152,7 @@ int wp_free(void *addr, long size)
>  	return 0;
>  }
>  
> -int wp_addr_range(void *addr, int size)
> +int wp_addr_range(void *addr, size_t size)
>  {
>  	if (pagemap_ioctl(addr, size, NULL, 0,
>  			  PM_SCAN_WP_MATCHING | PM_SCAN_CHECK_WPASYNC,
> @@ -787,7 +787,7 @@ int base_tests(char *prefix, char *mem, unsigned long long mem_size, int skip)
>  	return 0;
>  }
>  
> -void *gethugepage(int map_size)
> +void *gethugepage(size_t map_size)
>  {
>  	int ret;
>  	char *map;
> -- 
> 2.53.0
>