[PATCH 6.12 156/160] mm: use aligned address in clear_gigantic_page()

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6.12-stable review patch.  If anyone has any objections, please let me know.

------------------

From: Kefeng Wang <wangkefeng.wang@xxxxxxxxxx>

commit 8aca2bc96c833ba695ede7a45ad7784c836a262e upstream.

In current kernel, hugetlb_no_page() calls folio_zero_user() with the
fault address.  Where the fault address may be not aligned with the huge
page size.  Then, folio_zero_user() may call clear_gigantic_page() with
the address, while clear_gigantic_page() requires the address to be huge
page size aligned.  So, this may cause memory corruption or information
leak, addtional, use more obvious naming 'addr_hint' instead of 'addr' for
clear_gigantic_page().

Link: https://lkml.kernel.org/r/20241028145656.932941-1-wangkefeng.wang@xxxxxxxxxx
Fixes: 78fefd04c123 ("mm: memory: convert clear_huge_page() to folio_zero_user()")
Signed-off-by: Kefeng Wang <wangkefeng.wang@xxxxxxxxxx>
Reviewed-by: "Huang, Ying" <ying.huang@xxxxxxxxx>
Reviewed-by: David Hildenbrand <david@xxxxxxxxxx>
Cc: Matthew Wilcox (Oracle) <willy@xxxxxxxxxxxxx>
Cc: Muchun Song <muchun.song@xxxxxxxxx>
Cc: <stable@xxxxxxxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
 fs/hugetlbfs/inode.c |    2 +-
 mm/memory.c          |    3 ++-
 2 files changed, 3 insertions(+), 2 deletions(-)

--- a/fs/hugetlbfs/inode.c
+++ b/fs/hugetlbfs/inode.c
@@ -893,7 +893,7 @@ static long hugetlbfs_fallocate(struct f
 			error = PTR_ERR(folio);
 			goto out;
 		}
-		folio_zero_user(folio, ALIGN_DOWN(addr, hpage_size));
+		folio_zero_user(folio, addr);
 		__folio_mark_uptodate(folio);
 		error = hugetlb_add_to_page_cache(folio, mapping, index);
 		if (unlikely(error)) {
--- a/mm/memory.c
+++ b/mm/memory.c
@@ -6780,9 +6780,10 @@ static inline int process_huge_page(
 	return 0;
 }
 
-static void clear_gigantic_page(struct folio *folio, unsigned long addr,
+static void clear_gigantic_page(struct folio *folio, unsigned long addr_hint,
 				unsigned int nr_pages)
 {
+	unsigned long addr = ALIGN_DOWN(addr_hint, folio_size(folio));
 	int i;
 
 	might_sleep();






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