Commit 274fe92d authored by Oscar Salvador's avatar Oscar Salvador Committed by Andrew Morton
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mm, hugetlb: increment the number of pages to be reset on HVO 

commit 4eeec8c8 ("mm: move hugetlb specific things in folio to
page[3]") shifted hugetlb specific stuff, and now mapping overlaps
_hugetlb_cgroup field.

Upon restoring the vmemmap for HVO, only the first two tail pages are
reset, and this causes the check in free_tail_page_prepare() to fail as it
finds an unexpected mapping value in some tails.

Increment the number of pages to be reset to 4 (head + 3 tail pages)

Link: https://lkml.kernel.org/r/20250415111859.376302-1-osalvador@suse.de


Fixes: 4eeec8c8 ("mm: move hugetlb specific things in folio to page[3]")
Signed-off-by: default avatarOscar Salvador <osalvador@suse.de>
Suggested-by: default avatarDavid Hildenbrand <david@redhat.com>
Reviewed-by: default avatarDavid Hildenbrand <david@redhat.com>
Reviewed-by: default avatarMuchun Song <muchun.song@linux.dev>
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
parent 9e888998

mm/hugetlb_vmemmap.c

+3 −3
Original line number Diff line number Diff line
@@ -238,11 +238,11 @@ static void vmemmap_remap_pte(pte_t *pte, unsigned long addr, 
 * struct page, the special metadata (e.g. page->flags or page->mapping)

 * cannot copy to the tail struct page structs. The invalid value will be

 * checked in the free_tail_page_prepare(). In order to avoid the message

 * of "corrupted mapping in tail page". We need to reset at least 3 (one

 * head struct page struct and two tail struct page structs) struct page

 * of "corrupted mapping in tail page". We need to reset at least 4 (one

 * head struct page struct and three tail struct page structs) struct page

 * structs.

 */

#define NR_RESET_STRUCT_PAGE		3

#define NR_RESET_STRUCT_PAGE		4



static inline void reset_struct_pages(struct page *start)

{