mm-debug_page_alloc-fix-null-buf-in-debug_guardpage_minorder_setup.patch removed from -mm tree

The quilt patch titled
Subject: mm: debug_page_alloc: fix NULL buf in debug_guardpage_minorder_setup
has been removed from the -mm tree. Its filename was
mm-debug_page_alloc-fix-null-buf-in-debug_guardpage_minorder_setup.patch

This patch was dropped because it was merged into the mm-stable branch of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm

------------------------------------------------------
From: Ye Liu <[email protected]>
Subject: mm: debug_page_alloc: fix NULL buf in debug_guardpage_minorder_setup
Date: Thu, 6 Aug 2026 08:45:55 +0800

If the kernel command line includes "debug_guardpage_minorder" without an equals sign (i.e., no value is provided), the early parameter parser passes a NULL buf pointer to the setup function.

kstrtouint() does not perform a NULL check on its input and calls directly into kstrtoull() which dereferences s[0] unconditionally, leading to a NULL pointer dereference and early boot crash.

Additionally, the error path's pr_err("%s", buf) would also crash with a NULL format argument.

---

 mm/debug_page_alloc.c |    4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

@@ -22,8 +22,8 @@ static int __init debug_guardpage_minord
 {
 	unsigned int res;
 
-	if (kstrtouint(buf, 10, &res) < 0 ||  res > MAX_PAGE_ORDER / 2) {
-		pr_err("Bad debug_guardpage_minorder value: %s\n", buf);
+	if (!buf || kstrtouint(buf, 10, &res) < 0 || res > MAX_PAGE_ORDER / 2) {
+		pr_err("Bad debug_guardpage_minorder value: %s\n", buf ?: "(missing)");
 		return 0;
 	}
 	_debug_guardpage_minorder = res;

_

Patches currently in -mm which might be from [email protected] are