The patch titled
Subject: mm: use aligned address in clear_gigantic_page()
has been added to the -mm mm-unstable branch. Its filename is
mm-use-aligned-address-in-clear_gigantic_page.patch
This patch will shortly appear at
https://git.kernel.org/pub/scm/linux/kernel/git/akpm/25-new.git/tree/patches/mm-use-aligned-address-in-clear_gigantic_page.patch
This patch will later appear in the mm-unstable branch at
git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm
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------------------------------------------------------
From: Kefeng Wang <wangkefeng.wang@xxxxxxxxxx>
Subject: mm: use aligned address in clear_gigantic_page()
Date: Mon, 28 Oct 2024 22:56:55 +0800
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>
Cc: David Hildenbrand <david@xxxxxxxxxx>
Cc: Huang Ying <ying.huang@xxxxxxxxx>
Cc: Matthew Wilcox (Oracle) <willy@xxxxxxxxxxxxx>
Cc: Muchun Song <muchun.song@xxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
fs/hugetlbfs/inode.c | 2 +-
mm/memory.c | 3 ++-
2 files changed, 3 insertions(+), 2 deletions(-)
--- a/fs/hugetlbfs/inode.c~mm-use-aligned-address-in-clear_gigantic_page
+++ a/fs/hugetlbfs/inode.c
@@ -819,7 +819,7 @@ 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~mm-use-aligned-address-in-clear_gigantic_page
+++ a/mm/memory.c
@@ -6804,9 +6804,10 @@ 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();
_
Patches currently in -mm which might be from wangkefeng.wang@xxxxxxxxxx are
mm-remove-unused-hugepage-for-vma_alloc_folio.patch
tmpfs-dont-enable-large-folios-if-not-supported.patch
mm-huge_memory-move-file_thp_enabled-into-huge_memoryc.patch
mm-shmem-remove-__shmem_huge_global_enabled.patch
mm-use-aligned-address-in-clear_gigantic_page.patch
mm-use-aligned-address-in-copy_user_gigantic_page.patch
