On 11/13/25 23:07, David Hildenbrand (Red Hat) wrote: > On 13.11.25 12:56, Lorenzo Stoakes wrote: >> On Thu, Nov 13, 2025 at 04:13:52PM +1100, Balbir Singh wrote: >>> The softleaf changes exposed a BUG in remove_rmap_pmd() where the >>> migration entry was being overridden when the folio is device private. >>> >>> Use scope local entry for creating the device private pmde. Make the >>> pmde writable if the migration entry is writable by moving the check >>> softleaf_is_migration_write() prior to creating the device private entry. >>> >>> Cc: Andrew Morton <[email protected]> >>> Cc: David Hildenbrand <[email protected]> >>> Cc: Zi Yan <[email protected]> >>> Cc: Joshua Hahn <[email protected]> >>> Cc: Rakie Kim <[email protected]> >>> Cc: Byungchul Park <[email protected]> >>> Cc: Gregory Price <[email protected]> >>> Cc: Ying Huang <[email protected]> >>> Cc: Alistair Popple <[email protected]> >>> Cc: Oscar Salvador <[email protected]> >>> Cc: Lorenzo Stoakes <[email protected]> >>> Cc: Baolin Wang <[email protected]> >>> Cc: "Liam R. Howlett" <[email protected]> >>> Cc: Nico Pache <[email protected]> >>> Cc: Ryan Roberts <[email protected]> >>> Cc: Dev Jain <[email protected]> >>> Cc: Barry Song <[email protected]> >>> Cc: Lyude Paul <[email protected]> >>> Cc: Danilo Krummrich <[email protected]> >>> Cc: David Airlie <[email protected]> >>> Cc: Simona Vetter <[email protected]> >>> Cc: Ralph Campbell <[email protected]> >>> Cc: Mika Penttilä <[email protected]> >>> Cc: Matthew Brost <[email protected]> >>> Cc: Francois Dugast <[email protected]> >>> >>> Signed-off-by: Balbir Singh <[email protected]> >> >> THe logic LGTM but we don't want to have a bisect hazard here by having the >> bug >> introduced earlier then resolved here. > > Exactly. >
The hazard is a VM_WARN_ON() that checks for is_migration_entry() in the call to softleaf_is_migration_young(). I am happy to go down that path, let me send out the fixups, it felt weird to break the rebase, but I am sure Andrew has a better way of dealing with this stuff. Balbir
