[PATCH] mm: debug_page_alloc: fix type mismatch for debug_guardpage_minorder

[PATCH] mm: debug_page_alloc: fix type mismatch for debug_guardpage_minorder

[Ye Liu]

From: Ye Liu <liuye@kylinos.cn>

The _debug_guardpage_minorder variable is declared as unsigned int,
but the debug_guardpage_minorder_setup() function uses unsigned long
and kstrtoul() to parse the value.

Use kstrtouint() with unsigned int local variable to match the actual
type of _debug_guardpage_minorder.  Also fix the format specifier
from %lu to %u accordingly.

Signed-off-by: Ye Liu <liuye@kylinos.cn>
---
 mm/debug_page_alloc.c | 6 +++---
 1 file changed, 3 insertions(+), 3 deletions(-)

diff --git a/mm/debug_page_alloc.c b/mm/debug_page_alloc.c
index 6a26eca546c3..41e3d1f1ad96 100644
--- a/mm/debug_page_alloc.c
+++ b/mm/debug_page_alloc.c
@@ -20,14 +20,14 @@ early_param("debug_pagealloc", early_debug_pagealloc);
 
 static int __init debug_guardpage_minorder_setup(char *buf)
 {
-	unsigned long res;
+	unsigned int res;
 
-	if (kstrtoul(buf, 10, &res) < 0 ||  res > MAX_PAGE_ORDER / 2) {
+	if (kstrtouint(buf, 10, &res) < 0 ||  res > MAX_PAGE_ORDER / 2) {
 		pr_err("Bad debug_guardpage_minorder value: %s\n", buf);
 		return 0;
 	}
 	_debug_guardpage_minorder = res;
-	pr_info("Setting debug_guardpage_minorder to %lu\n", res);
+	pr_info("Setting debug_guardpage_minorder to %u\n", res);
 	return 0;
 }
 early_param("debug_guardpage_minorder", debug_guardpage_minorder_setup);
-- 
2.25.1

Re: [PATCH] mm: debug_page_alloc: fix type mismatch for debug_guardpage_minorder

[Andrew Morton]

On Wed,  5 Aug 2026 17:31:07 +0800 Ye Liu <ye.liu@linux.dev> wrote:

> 
> The _debug_guardpage_minorder variable is declared as unsigned int,
> but the debug_guardpage_minorder_setup() function uses unsigned long
> and kstrtoul() to parse the value.
> 
> Use kstrtouint() with unsigned int local variable to match the actual
> type of _debug_guardpage_minorder.  Also fix the format specifier
> from %lu to %u accordingly.

Fair enough, thanks.

AI review seems to have found a little pre-existing bug in there, 
	https://sashiko.dev/#/patchset/20260805093108.2352900-1-ye.liu@linux.dev