[alternative-merged] mm-add-pte_present-check-on-existing-hugetlb_entry-callbacks.patch removed from -mm tree

[alternative-merged] mm-add-pte_present-check-on-existing-hugetlb_entry-callbacks.patch removed from -mm tree

[akpm]

Subject: [alternative-merged] mm-add-pte_present-check-on-existing-hugetlb_entry-callbacks.patch removed from -mm tree
To: n-horiguchi@ah.jp.nec.com,riel@redhat.com,sasha.levin@oracle.com,stable@vger.kernel.org,mm-commits@vger.kernel.org
From: akpm@linux-foundation.org
Date: Mon, 09 Jun 2014 11:59:02 -0700


The patch titled
     Subject: mm: add !pte_present() check on existing hugetlb_entry callbacks
has been removed from the -mm tree.  Its filename was
     mm-add-pte_present-check-on-existing-hugetlb_entry-callbacks.patch

This patch was dropped because an alternative patch was merged

------------------------------------------------------
From: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com>
Subject: mm: add !pte_present() check on existing hugetlb_entry callbacks

Page table walker doesn't check non-present hugetlb entry in common path,
so hugetlb_entry() callbacks must check it.  The reason for this behavior
is that some callers want to handle it in its own way.

However, some callers don't check it now, which causes unpredictable
result, for example when we have a race between migrating hugepage and
reading /proc/pid/numa_maps.  This patch fixes it by adding !pte_present
checks on buggy callbacks.

This bug exists for years and got visible by introducing hugepage migration.

ChangeLog v2:
- fix if condition (check !pte_present() instead of pte_present())

Reported-by: Sasha Levin <sasha.levin@oracle.com>
Signed-off-by: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com>
Cc: Rik van Riel <riel@redhat.com>
Cc: <stable@vger.kernel.org>	[3.12+]
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
---

 fs/proc/task_mmu.c |    3 +++
 mm/mempolicy.c     |    6 +++++-
 2 files changed, 8 insertions(+), 1 deletion(-)

diff -puN fs/proc/task_mmu.c~mm-add-pte_present-check-on-existing-hugetlb_entry-callbacks fs/proc/task_mmu.c
--- a/fs/proc/task_mmu.c~mm-add-pte_present-check-on-existing-hugetlb_entry-callbacks
+++ a/fs/proc/task_mmu.c
@@ -1300,6 +1300,9 @@ static int gather_hugetlb_stats(pte_t *p
 	if (pte_none(*pte))
 		return 0;
 
+	if (!pte_present(*pte))
+		return 0;
+
 	page = pte_page(*pte);
 	if (!page)
 		return 0;
diff -puN mm/mempolicy.c~mm-add-pte_present-check-on-existing-hugetlb_entry-callbacks mm/mempolicy.c
--- a/mm/mempolicy.c~mm-add-pte_present-check-on-existing-hugetlb_entry-callbacks
+++ a/mm/mempolicy.c
@@ -524,8 +524,12 @@ static int queue_pages_hugetlb(pte_t *pt
 	unsigned long flags = qp->flags;
 	int nid;
 	struct page *page;
+	pte_t entry;
 
-	page = pte_page(huge_ptep_get(pte));
+	entry = huge_ptep_get(pte);
+	if (!pte_present(entry))
+		return 0;
+	page = pte_page(entry);
 	nid = page_to_nid(page);
 	if (node_isset(nid, *qp->nmask) == !!(flags & MPOL_MF_INVERT))
 		return 0;
_

Patches currently in -mm which might be from n-horiguchi@ah.jp.nec.com are

origin.patch
mm-hugetlbfs-fix-rmapping-for-anonymous-hugepages-with-page_pgoff.patch
mm-hugetlbfs-fix-rmapping-for-anonymous-hugepages-with-page_pgoff-v2.patch
mm-hugetlbfs-fix-rmapping-for-anonymous-hugepages-with-page_pgoff-v3.patch
mm-hugetlbfs-fix-rmapping-for-anonymous-hugepages-with-page_pgoff-v3-fix.patch
pagewalk-update-page-table-walker-core.patch
pagewalk-update-page-table-walker-core-fix-end-address-calculation-in-walk_page_range.patch
pagewalk-update-page-table-walker-core-fix-end-address-calculation-in-walk_page_range-fix.patch
pagewalk-update-page-table-walker-core-fix.patch
pagewalk-add-walk_page_vma.patch
smaps-redefine-callback-functions-for-page-table-walker.patch
clear_refs-redefine-callback-functions-for-page-table-walker.patch
pagemap-redefine-callback-functions-for-page-table-walker.patch
pagemap-redefine-callback-functions-for-page-table-walker-fix.patch
numa_maps-redefine-callback-functions-for-page-table-walker.patch
memcg-redefine-callback-functions-for-page-table-walker.patch
arch-powerpc-mm-subpage-protc-use-walk_page_vma-instead-of-walk_page_range.patch
pagewalk-remove-argument-hmask-from-hugetlb_entry.patch
pagewalk-remove-argument-hmask-from-hugetlb_entry-fix.patch
pagewalk-remove-argument-hmask-from-hugetlb_entry-fix-fix.patch
mempolicy-apply-page-table-walker-on-queue_pages_range.patch
mm-pagewalkc-move-pte-null-check.patch
mm-prom-pid-clear_refs-avoid-split_huge_page.patch
mm-introduce-do_shared_fault-and-drop-do_fault-fix-fix.patch
do_shared_fault-check-that-mmap_sem-is-held.patch
linux-next.patch