--- /dev/null
+From a7f40cfe3b7ada57af9b62fd28430eeb4a7cfcb7 Mon Sep 17 00:00:00 2001
+From: Yang Shi <yang.shi@linux.alibaba.com>
+Date: Thu, 28 Mar 2019 20:43:55 -0700
+Subject: mm: mempolicy: make mbind() return -EIO when MPOL_MF_STRICT is specified
+
+From: Yang Shi <yang.shi@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
+
+[akpm@linux-foundation.org: tweak code comment]
+Link: http://lkml.kernel.org/r/1553020556-38583-1-git-send-email-yang.shi@linux.alibaba.com
+Fixes: 6f4576e3687b ("mempolicy: apply page table walker on queue_pages_range()")
+Signed-off-by: Yang Shi <yang.shi@linux.alibaba.com>
+Signed-off-by: Oscar Salvador <osalvador@suse.de>
+Reported-by: Cyril Hrubis <chrubis@suse.cz>
+Suggested-by: Kirill A. Shutemov <kirill@shutemov.name>
+Acked-by: Rafael Aquini <aquini@redhat.com>
+Reviewed-by: Oscar Salvador <osalvador@suse.de>
+Acked-by: David Rientjes <rientjes@google.com>
+Cc: Vlastimil Babka <vbabka@suse.cz>
+Cc: <stable@vger.kernel.org>
+Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
+Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
+Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
+
+
+---
+ mm/mempolicy.c | 40 +++++++++++++++++++++++++++++++++-------
+ 1 file changed, 33 insertions(+), 7 deletions(-)
+
+--- a/mm/mempolicy.c
++++ b/mm/mempolicy.c
+@@ -427,6 +427,13 @@ static inline bool queue_pages_required(
+ return node_isset(nid, *qp->nmask) == !(flags & MPOL_MF_INVERT);
+ }
+
++/*
++ * queue_pages_pmd() has three possible return values:
++ * 1 - pages are placed on the right node or queued successfully.
++ * 0 - THP was split.
++ * -EIO - is migration entry or MPOL_MF_STRICT was specified and an existing
++ * page was already on a node that does not follow the policy.
++ */
+ static int queue_pages_pmd(pmd_t *pmd, spinlock_t *ptl, unsigned long addr,
+ unsigned long end, struct mm_walk *walk)
+ {
+@@ -436,7 +443,7 @@ static int queue_pages_pmd(pmd_t *pmd, s
+ unsigned long flags;
+
+ if (unlikely(is_pmd_migration_entry(*pmd))) {
+- ret = 1;
++ ret = -EIO;
+ goto unlock;
+ }
+ page = pmd_page(*pmd);
+@@ -462,8 +469,15 @@ static int queue_pages_pmd(pmd_t *pmd, s
+ ret = 1;
+ flags = qp->flags;
+ /* go to thp migration */
+- if (flags & (MPOL_MF_MOVE | MPOL_MF_MOVE_ALL))
++ if (flags & (MPOL_MF_MOVE | MPOL_MF_MOVE_ALL)) {
++ if (!vma_migratable(walk->vma)) {
++ ret = -EIO;
++ goto unlock;
++ }
++
+ migrate_page_add(page, qp->pagelist, flags);
++ } else
++ ret = -EIO;
+ unlock:
+ spin_unlock(ptl);
+ out:
+@@ -488,8 +502,10 @@ static int queue_pages_pte_range(pmd_t *
+ ptl = pmd_trans_huge_lock(pmd, vma);
+ if (ptl) {
+ ret = queue_pages_pmd(pmd, ptl, addr, end, walk);
+- if (ret)
++ if (ret > 0)
+ return 0;
++ else if (ret < 0)
++ return ret;
+ }
+
+ if (pmd_trans_unstable(pmd))
+@@ -526,11 +542,16 @@ 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,
+@@ -600,7 +621,12 @@ 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)
+@@ -627,7 +653,7 @@ 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;
+ }
projects / thirdparty / kernel / stable-queue.git / blobdiff