[PATCH] mm/page_owner: fix %pGp format specifier argument type

[PATCH] mm/page_owner: fix %pGp format specifier argument type

[Zhen Ni]

The %pGp format specifier expects an argument of type 'unsigned long *',
but page->flags is now of type 'memdesc_flags_t' (a struct containing
an unsigned long member 'f') after the introduction of memdesc_flags_t.

Fix the type mismatch by passing &page->flags.f instead of &page->flags,
which matches the expected type.

Fixes: 53fbef56e07d ("mm: introduce memdesc_flags_t")
Signed-off-by: Zhen Ni <zhen.ni@easystack.cn>
---
 mm/page_owner.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/mm/page_owner.c b/mm/page_owner.c
index 8178e0be557f..2dddcb6510aa 100644
--- a/mm/page_owner.c
+++ b/mm/page_owner.c
@@ -573,7 +573,7 @@ print_page_owner(char __user *buf, size_t count, unsigned long pfn,
 			migratetype_names[page_mt],
 			pfn >> pageblock_order,
 			migratetype_names[pageblock_mt],
-			&page->flags);
+			&page->flags.f);
 
 	ret += stack_depot_snprint(handle, kbuf + ret, count - ret, 0);
 	if (ret >= count)
-- 
2.20.1

Re: [PATCH] mm/page_owner: fix %pGp format specifier argument type

[Vlastimil Babka (SUSE)]

On 4/14/26 09:58, Zhen Ni wrote:
> The %pGp format specifier expects an argument of type 'unsigned long *',
> but page->flags is now of type 'memdesc_flags_t' (a struct containing
> an unsigned long member 'f') after the introduction of memdesc_flags_t.
> 
> Fix the type mismatch by passing &page->flags.f instead of &page->flags,
> which matches the expected type.

I think this has no visible effects as memdesc_flags_t just wraps unsigned
long, so it's not an urgent fix. Things could break if we modified
memdesc_flags_t further, or compiler/some tool got smart enough to flag the
mismath.

> Fixes: 53fbef56e07d ("mm: introduce memdesc_flags_t")
> Signed-off-by: Zhen Ni <zhen.ni@easystack.cn>

Acked-by: Vlastimil Babka (SUSE) <vbabka@kernel.org>

> ---
>  mm/page_owner.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/mm/page_owner.c b/mm/page_owner.c
> index 8178e0be557f..2dddcb6510aa 100644
> --- a/mm/page_owner.c
> +++ b/mm/page_owner.c
> @@ -573,7 +573,7 @@ print_page_owner(char __user *buf, size_t count, unsigned long pfn,
>  			migratetype_names[page_mt],
>  			pfn >> pageblock_order,
>  			migratetype_names[pageblock_mt],
> -			&page->flags);
> +			&page->flags.f);
>  
>  	ret += stack_depot_snprint(handle, kbuf + ret, count - ret, 0);
>  	if (ret >= count)