[merged mm-stable] mm-expose-abnormal-new_pte-during-move_ptes.patch removed from -mm tree

[merged mm-stable] mm-expose-abnormal-new_pte-during-move_ptes.patch removed from -mm tree

[Andrew Morton]

The quilt patch titled
     Subject: mm: expose abnormal new_pte during move_ptes
has been removed from the -mm tree.  Its filename was
     mm-expose-abnormal-new_pte-during-move_ptes.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: Pu Lehui <pulehui@huawei.com>
Subject: mm: expose abnormal new_pte during move_ptes
Date: Thu, 29 May 2025 15:56:48 +0000

When executing move_ptes, the new_pte must be NULL, otherwise it will be
overwritten by the old_pte, and cause the abnormal new_pte to be leaked. 
In order to make this problem to be more explicit, let's add WARN_ON_ONCE
when new_pte is not NULL.

[akpm@linux-foundation.org: s/WARN_ON_ONCE/VM_WARN_ON_ONCE/]
Link: https://lkml.kernel.org/r/20250529155650.4017699-3-pulehui@huaweicloud.com
Suggested-by: Oleg Nesterov <oleg@redhat.com>
Signed-off-by: Pu Lehui <pulehui@huawei.com>
Reviewed-by: Lorenzo Stoakes <lorenzo.stoakes@oracle.com>
Cc: Jann Horn <jannh@google.com>
Cc: Liam Howlett <liam.howlett@oracle.com>
Cc: "Masami Hiramatsu (Google)" <mhiramat@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Vlastimil Babka <vbabka@suse.cz>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
---

 mm/mremap.c |    2 ++
 1 file changed, 2 insertions(+)

--- a/mm/mremap.c~mm-expose-abnormal-new_pte-during-move_ptes
+++ a/mm/mremap.c
@@ -237,6 +237,8 @@ static int move_ptes(struct pagetable_mo
 
 	for (; old_addr < old_end; old_pte++, old_addr += PAGE_SIZE,
 				   new_pte++, new_addr += PAGE_SIZE) {
+		VM_WARN_ON_ONCE(!pte_none(*new_pte));
+
 		if (pte_none(ptep_get(old_pte)))
 			continue;
 
_

Patches currently in -mm which might be from pulehui@huawei.com are