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. I think better would be to do the fix up in the original series as a fix-patch, then maybe point at this one as a conflict resolution for my series? In any case, LGTM so: Reviewed-by: Lorenzo Stoakes <[email protected]> > --- > mm/huge_memory.c | 7 +++++-- > 1 file changed, 5 insertions(+), 2 deletions(-) > > diff --git a/mm/huge_memory.c b/mm/huge_memory.c > index 0184cd915f44..e4dadcb9e90b 100644 > --- a/mm/huge_memory.c > +++ b/mm/huge_memory.c > @@ -4850,7 +4850,12 @@ void remove_migration_pmd(struct page_vma_mapped_walk > *pvmw, struct page *new) > folio_get(folio); > pmde = folio_mk_pmd(folio, READ_ONCE(vma->vm_page_prot)); > > + if (softleaf_is_migration_write(entry)) > + pmde = pmd_mkwrite(pmde, vma); > + > if (folio_is_device_private(folio)) { > + swp_entry_t entry; > + > if (pmd_write(pmde)) > entry = make_writable_device_private_entry( > page_to_pfn(new)); > @@ -4862,8 +4867,6 @@ void remove_migration_pmd(struct page_vma_mapped_walk > *pvmw, struct page *new) > > if (pmd_swp_soft_dirty(*pvmw->pmd)) > pmde = pmd_mksoft_dirty(pmde); > - if (softleaf_is_migration_write(entry)) > - pmde = pmd_mkwrite(pmde, vma); > if (pmd_swp_uffd_wp(*pvmw->pmd)) > pmde = pmd_mkuffd_wp(pmde); > if (!softleaf_is_migration_young(entry)) > -- > 2.51.1 >
