From 72d2ddf5f2218861f41b7d1a9da4c130d6d81911 Mon Sep 17 00:00:00 2001 From: Cyrill Gorcunov Date: Wed, 16 Oct 2013 13:46:51 -0700 Subject: [PATCH] mm: migration: do not lose soft dirty bit if page is in migration state commit c3d16e16522fe3fe8759735850a0676da18f4b1d upstream. If page migration is turned on in config and the page is migrating, we may lose the soft dirty bit. If fork and mprotect are called on migrating pages (once migration is complete) pages do not obtain the soft dirty bit in the correspond pte entries. Fix it adding an appropriate test on swap entries. Signed-off-by: Cyrill Gorcunov Cc: Pavel Emelyanov Cc: Andy Lutomirski Cc: Matt Mackall Cc: Xiao Guangrong Cc: Marcelo Tosatti Cc: KOSAKI Motohiro Cc: Stephen Rothwell Cc: Peter Zijlstra Cc: "Aneesh Kumar K.V" Cc: Naoya Horiguchi Cc: Mel Gorman Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds Signed-off-by: Greg Kroah-Hartman --- mm/memory.c | 2 ++ mm/migrate.c | 2 ++ mm/mprotect.c | 7 +++++-- 3 files changed, 9 insertions(+), 2 deletions(-) diff --git a/mm/memory.c b/mm/memory.c index af84bc0ec17c2..440986e572180 100644 --- a/mm/memory.c +++ b/mm/memory.c @@ -861,6 +861,8 @@ copy_one_pte(struct mm_struct *dst_mm, struct mm_struct *src_mm, */ make_migration_entry_read(&entry); pte = swp_entry_to_pte(entry); + if (pte_swp_soft_dirty(*src_pte)) + pte = pte_swp_mksoft_dirty(pte); set_pte_at(src_mm, addr, src_pte, pte); } } diff --git a/mm/migrate.c b/mm/migrate.c index 25ca7caf9092a..81af4e678101e 100644 --- a/mm/migrate.c +++ b/mm/migrate.c @@ -157,6 +157,8 @@ static int remove_migration_pte(struct page *new, struct vm_area_struct *vma, get_page(new); pte = pte_mkold(mk_pte(new, vma->vm_page_prot)); + if (pte_swp_soft_dirty(*ptep)) + pte = pte_mksoft_dirty(pte); if (is_write_migration_entry(entry)) pte = pte_mkwrite(pte); #ifdef CONFIG_HUGETLB_PAGE diff --git a/mm/mprotect.c b/mm/mprotect.c index 94722a4d6b438..a3af058f68e4d 100644 --- a/mm/mprotect.c +++ b/mm/mprotect.c @@ -94,13 +94,16 @@ static unsigned long change_pte_range(struct vm_area_struct *vma, pmd_t *pmd, swp_entry_t entry = pte_to_swp_entry(oldpte); if (is_write_migration_entry(entry)) { + pte_t newpte; /* * A protection check is difficult so * just be safe and disable write */ make_migration_entry_read(&entry); - set_pte_at(mm, addr, pte, - swp_entry_to_pte(entry)); + newpte = swp_entry_to_pte(entry); + if (pte_swp_soft_dirty(oldpte)) + newpte = pte_swp_mksoft_dirty(newpte); + set_pte_at(mm, addr, pte, newpte); } pages++; } -- 2.47.3