From: Peter Xu Date: Thu, 16 Feb 2023 15:30:59 +0000 (-0500) Subject: mm/migrate: fix wrongly apply write bit after mkdirty on sparc64 X-Git-Tag: v6.1.15~138 X-Git-Url: http://review.tizen.org/git/?a=commitdiff_plain;h=54806cb7516c2ad0cb9887a8ef1a0c4df914837f;p=platform%2Fkernel%2Flinux-starfive.git mm/migrate: fix wrongly apply write bit after mkdirty on sparc64 commit 96a9c287e25d690fd9623b5133703b8e310fbed1 upstream. Nick Bowler reported another sparc64 breakage after the young/dirty persistent work for page migration (per "Link:" below). That's after a similar report [2]. It turns out page migration was overlooked, and it wasn't failing before because page migration was not enabled in the initial report test environment. David proposed another way [2] to fix this from sparc64 side, but that patch didn't land somehow. Neither did I check whether there's any other arch that has similar issues. Let's fix it for now as simple as moving the write bit handling to be after dirty, like what we did before. Note: this is based on mm-unstable, because the breakage was since 6.1 and we're at a very late stage of 6.2 (-rc8), so I assume for this specific case we should target this at 6.3. [1] https://lore.kernel.org/all/20221021160603.GA23307@u164.east.ru/ [2] https://lore.kernel.org/all/20221212130213.136267-1-david@redhat.com/ Link: https://lkml.kernel.org/r/20230216153059.256739-1-peterx@redhat.com Fixes: 2e3468778dbe ("mm: remember young/dirty bit for page migrations") Link: https://lore.kernel.org/all/CADyTPExpEqaJiMGoV+Z6xVgL50ZoMJg49B10LcZ=8eg19u34BA@mail.gmail.com/ Signed-off-by: Peter Xu Reported-by: Nick Bowler Acked-by: David Hildenbrand Tested-by: Nick Bowler Cc: Cc: Signed-off-by: Andrew Morton Signed-off-by: Greg Kroah-Hartman --- diff --git a/mm/huge_memory.c b/mm/huge_memory.c index 811d19b..e7cf013a 100644 --- a/mm/huge_memory.c +++ b/mm/huge_memory.c @@ -3253,8 +3253,6 @@ void remove_migration_pmd(struct page_vma_mapped_walk *pvmw, struct page *new) pmde = mk_huge_pmd(new, READ_ONCE(vma->vm_page_prot)); if (pmd_swp_soft_dirty(*pvmw->pmd)) pmde = pmd_mksoft_dirty(pmde); - if (is_writable_migration_entry(entry)) - pmde = maybe_pmd_mkwrite(pmde, vma); if (pmd_swp_uffd_wp(*pvmw->pmd)) pmde = pmd_wrprotect(pmd_mkuffd_wp(pmde)); if (!is_migration_entry_young(entry)) @@ -3262,6 +3260,10 @@ void remove_migration_pmd(struct page_vma_mapped_walk *pvmw, struct page *new) /* NOTE: this may contain setting soft-dirty on some archs */ if (PageDirty(new) && is_migration_entry_dirty(entry)) pmde = pmd_mkdirty(pmde); + if (is_writable_migration_entry(entry)) + pmde = maybe_pmd_mkwrite(pmde, vma); + else + pmde = pmd_wrprotect(pmde); if (PageAnon(new)) { rmap_t rmap_flags = RMAP_COMPOUND; diff --git a/mm/migrate.c b/mm/migrate.c index dff3335..8d5c0dc 100644 --- a/mm/migrate.c +++ b/mm/migrate.c @@ -215,6 +215,8 @@ static bool remove_migration_pte(struct folio *folio, pte = maybe_mkwrite(pte, vma); else if (pte_swp_uffd_wp(*pvmw.pte)) pte = pte_mkuffd_wp(pte); + else + pte = pte_wrprotect(pte); if (folio_test_anon(folio) && !is_readable_migration_entry(entry)) rmap_flags |= RMAP_EXCLUSIVE;