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authorPeter Xu <peterx@redhat.com>2023-02-16 18:30:59 +0300
committerAndrew Morton <akpm@linux-foundation.org>2023-02-18 02:07:05 +0300
commit96a9c287e25d690fd9623b5133703b8e310fbed1 (patch)
tree24903660de8c1cc01e78bd5b2ca947e64fe3d339 /mm
parent5c7388bcd59df59fe527246526bbdf8b9dedf8cc (diff)
downloadlinux-96a9c287e25d690fd9623b5133703b8e310fbed1.tar.xz
mm/migrate: fix wrongly apply write bit after mkdirty on sparc64
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 <peterx@redhat.com> Reported-by: Nick Bowler <nbowler@draconx.ca> Acked-by: David Hildenbrand <david@redhat.com> Tested-by: Nick Bowler <nbowler@draconx.ca> Cc: <regressions@lists.linux.dev> Cc: <stable@vger.kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Diffstat (limited to 'mm')
-rw-r--r--mm/huge_memory.c6
-rw-r--r--mm/migrate.c2
2 files changed, 6 insertions, 2 deletions
diff --git a/mm/huge_memory.c b/mm/huge_memory.c
index abe6cfd92ffa..1b791b26d72d 100644
--- a/mm/huge_memory.c
+++ b/mm/huge_memory.c
@@ -3272,8 +3272,6 @@ 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))
@@ -3281,6 +3279,10 @@ 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 a4d3fc65085f..cc5455614e01 100644
--- a/mm/migrate.c
+++ b/mm/migrate.c
@@ -224,6 +224,8 @@ 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;