On 7/3/26 13:41, Dev Jain wrote:

try_to_migrate_one() is used by folio migration to replace a present
mapping with a migration entry. For hugetlb folios, page_vma_mapped_walk()
returns the pte pointer to the hugetlb folio in pvmw.pte, but the code
reads the huge pte entry with ptep_get().

On arches which provide their own huge_ptep_get() to dereference a huge
pte pointer, accessing via ptep_get() would cause pte_pfn(), pte_present()
etc to misbehave.

It is not clear whether this has a trivially visible effect to userspace.

Use huge_ptep_get() to dereference a huge pte pointer.

Commit a98a2f0c8ce1 copied the bug from try_to_unmap_one into
try_to_migrate_one.

Fixes: a98a2f0c8ce1 ("mm/rmap: split migration into its own function")
Cc: stable@vger.kernel.org
Acked-by: Muchun Song <muchun.song@linux.dev>
Signed-off-by: Dev Jain <dev.jain@arm.com>
---

Acked-by: David Hildenbrand (Arm) <david@kernel.org>

-- 
Cheers,

David