4.9-stable review patch. If anyone has any objections, please let me know.
------------------
From: Yang Shi <yang....@linux.alibaba.com>
commit a7f40cfe3b7ada57af9b62fd28430eeb4a7cfcb7 upstream.
When MPOL_MF_STRICT was specified and an existing page was already on a
node that does not follow the policy, mbind() should return -EIO. But
commit 6f4576e3687b ("mempolicy: apply page table walker on
queue_pages_range()") broke the rule.
And commit c8633798497c ("mm: mempolicy: mbind and migrate_pages support
thp migration") didn't return the correct value for THP mbind() too.
If MPOL_MF_STRICT is set, ignore vma_migratable() to make sure it
reaches queue_pages_to_pte_range() or queue_pages_pmd() to check if an
existing page was already on a node that does not follow the policy.
And, non-migratable vma may be used, return -EIO too if MPOL_MF_MOVE or
MPOL_MF_MOVE_ALL was specified.
Tested with
https://github.com/metan-ucw/ltp/blob/master/testcases/kernel/syscalls/mbind/mbind02.c
[a...@linux-foundation.org: tweak code comment]
Link:
http://lkml.kernel.org/r/1553020556-38583-1-git-send-email-yang....@linux.alibaba.com
Fixes: 6f4576e3687b ("mempolicy: apply page table walker on
queue_pages_range()")
Signed-off-by: Yang Shi <yang....@linux.alibaba.com>
Signed-off-by: Oscar Salvador <osalva...@suse.de>
Reported-by: Cyril Hrubis <chru...@suse.cz>
Suggested-by: Kirill A. Shutemov <kir...@shutemov.name>
Acked-by: Rafael Aquini <aqu...@redhat.com>
Reviewed-by: Oscar Salvador <osalva...@suse.de>
Acked-by: David Rientjes <rient...@google.com>
Cc: Vlastimil Babka <vba...@suse.cz>
Cc: <sta...@vger.kernel.org>
Signed-off-by: Andrew Morton <a...@linux-foundation.org>
Signed-off-by: Linus Torvalds <torva...@linux-foundation.org>
Signed-off-by: Greg Kroah-Hartman <gre...@linuxfoundation.org>
---
mm/mempolicy.c | 18 ++++++++++++++----
1 file changed, 14 insertions(+), 4 deletions(-)
--- a/mm/mempolicy.c
+++ b/mm/mempolicy.c
@@ -547,11 +547,16 @@ retry:
goto retry;
}
- migrate_page_add(page, qp->pagelist, flags);
+ if (flags & (MPOL_MF_MOVE | MPOL_MF_MOVE_ALL)) {
+ if (!vma_migratable(vma))
+ break;
+ migrate_page_add(page, qp->pagelist, flags);
+ } else
+ break;
}
pte_unmap_unlock(pte - 1, ptl);
cond_resched();
- return 0;
+ return addr != end ? -EIO : 0;
}
static int queue_pages_hugetlb(pte_t *pte, unsigned long hmask,
@@ -623,7 +628,12 @@ static int queue_pages_test_walk(unsigne
unsigned long endvma = vma->vm_end;
unsigned long flags = qp->flags;
- if (!vma_migratable(vma))
+ /*
+ * Need check MPOL_MF_STRICT to return -EIO if possible
+ * regardless of vma_migratable
+ */
+ if (!vma_migratable(vma) &&
+ !(flags & MPOL_MF_STRICT))
return 1;
if (endvma > end)
@@ -650,7 +660,7 @@ static int queue_pages_test_walk(unsigne
}
/* queue pages from current vma */
- if (flags & (MPOL_MF_MOVE | MPOL_MF_MOVE_ALL))
+ if (flags & MPOL_MF_VALID)
return 0;
return 1;
}
