mm: use aligned address in clear_gigantic_page()

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@huawei.com
Fixes: 78fefd04c123 ("mm: memory: convert clear_huge_page() to folio_zero_user()")
Signed-off-by: Kefeng Wang <wangkefeng.wang@huawei.com>
Reviewed-by: "Huang, Ying" <ying.huang@intel.com>
Reviewed-by: David Hildenbrand <david@redhat.com>
Cc: Matthew Wilcox (Oracle) <willy@infradead.org>
Cc: Muchun Song <muchun.song@linux.dev>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

diff --git a/fs/hugetlbfs/inode.c b/fs/hugetlbfs/inode.c
index c6191a6118b83f40da4cb1e58c8c9c449c238839..33af1e0f72ef9ad8e27fabfb0e69a794ad9484b1 100644 (file)
--- a/fs/hugetlbfs/inode.c
+++ b/fs/hugetlbfs/inode.c
@@ -819,7 +819,7 @@ static long hugetlbfs_fallocate(struct file *file, int mode, loff_t offset,
                        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)) {

diff --git a/mm/memory.c b/mm/memory.c
index 2d32023d4eb87d737f7259ff77b48298bc5d385b..cb2e19ff24fcba69d5977de91955cfa2e468fd59 100644 (file)
--- a/mm/memory.c
+++ b/mm/memory.c
@@ -6803,9 +6803,10 @@ 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();