This is a note to let you know that I've just added the patch titled
mm/hugetlb: use nth_page() in place of direct struct page manipulation
to the 6.6-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary
The filename of the patch is:
mm-hugetlb-use-nth_page-in-place-of-direct-struct-page-manipulation.patch
and it can be found in the queue-6.6 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
>From 426056efe835cf4864ccf4c328fe3af9146fc539 Mon Sep 17 00:00:00 2001
From: Zi Yan <ziy@xxxxxxxxxx>
Date: Wed, 13 Sep 2023 16:12:45 -0400
Subject: mm/hugetlb: use nth_page() in place of direct struct page manipulation
From: Zi Yan <ziy@xxxxxxxxxx>
commit 426056efe835cf4864ccf4c328fe3af9146fc539 upstream.
When dealing with hugetlb pages, manipulating struct page pointers
directly can get to wrong struct page, since struct page is not guaranteed
to be contiguous on SPARSEMEM without VMEMMAP. Use nth_page() to handle
it properly.
A wrong or non-existing page might be tried to be grabbed, either
leading to a non freeable page or kernel memory access errors. No bug
is reported. It comes from code inspection.
Link: https://lkml.kernel.org/r/20230913201248.452081-3-zi.yan@xxxxxxxx
Fixes: 57a196a58421 ("hugetlb: simplify hugetlb handling in follow_page_mask")
Signed-off-by: Zi Yan <ziy@xxxxxxxxxx>
Reviewed-by: Muchun Song <songmuchun@xxxxxxxxxxxxx>
Cc: David Hildenbrand <david@xxxxxxxxxx>
Cc: Matthew Wilcox (Oracle) <willy@xxxxxxxxxxxxx>
Cc: Mike Kravetz <mike.kravetz@xxxxxxxxxx>
Cc: Mike Rapoport (IBM) <rppt@xxxxxxxxxx>
Cc: Thomas Bogendoerfer <tsbogend@xxxxxxxxxxxxxxxx>
Cc: <stable@xxxxxxxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
mm/hugetlb.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
--- a/mm/hugetlb.c
+++ b/mm/hugetlb.c
@@ -6520,7 +6520,7 @@ struct page *hugetlb_follow_page_mask(st
}
}
- page += ((address & ~huge_page_mask(h)) >> PAGE_SHIFT);
+ page = nth_page(page, ((address & ~huge_page_mask(h)) >> PAGE_SHIFT));
/*
* Note that page may be a sub-page, and with vmemmap
Patches currently in stable-queue which might be from ziy@xxxxxxxxxx are
queue-6.6/mm-memory_hotplug-use-pfn-math-in-place-of-direct-struct-page-manipulation.patch
queue-6.6/fs-use-nth_page-in-place-of-direct-struct-page-manipulation.patch
queue-6.6/mm-cma-use-nth_page-in-place-of-direct-struct-page-manipulation.patch
queue-6.6/mips-use-nth_page-in-place-of-direct-struct-page-manipulation.patch
queue-6.6/mm-hugetlb-use-nth_page-in-place-of-direct-struct-page-manipulation.patch
