Subject: + mm-add-pte_present-check-on-existing-hugetlb_entry-callbacks.patch
added to -mm tree
To:
[email protected],[email protected],[email protected],[email protected]
From: [email protected]
Date: Wed, 19 Mar 2014 13:25:22 -0700
The patch titled
Subject: mm: add !pte_present() check on existing hugetlb_entry callbacks
has been added to the -mm tree. Its filename is
mm-add-pte_present-check-on-existing-hugetlb_entry-callbacks.patch
This patch should soon appear at
http://ozlabs.org/~akpm/mmots/broken-out/mm-add-pte_present-check-on-existing-hugetlb_entry-callbacks.patch
and later at
http://ozlabs.org/~akpm/mmotm/broken-out/mm-add-pte_present-check-on-existing-hugetlb_entry-callbacks.patch
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------------------------------------------------------
From: Naoya Horiguchi <[email protected]>
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 <[email protected]>
Signed-off-by: Naoya Horiguchi <[email protected]>
Cc: Rik van Riel <[email protected]>
Cc: <[email protected]> [3.12+]
Signed-off-by: Andrew Morton <[email protected]>
---
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
@@ -1299,6 +1299,9 @@ 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 [email protected] are
mm-hugetlb-unify-region-structure-handling.patch
mm-hugetlb-improve-cleanup-resv_map-parameters.patch
mm-hugetlb-fix-race-in-region-tracking.patch
mm-hugetlb-remove-resv_map_put.patch
mm-hugetlb-use-vma_resv_map-map-types.patch
mm-hugetlb-improve-page-fault-scalability.patch
mm-hugetlb-improve-page-fault-scalability-fix.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-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
numa_maps-redefine-callback-functions-for-page-table-walker.patch
memcg-redefine-callback-functions-for-page-table-walker.patch
madvise-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-add-pte_present-check-on-existing-hugetlb_entry-callbacks.patch
mm-call-vma_adjust_trans_huge-only-for-thp-enabled-vma.patch
mm-rename-__do_fault-do_fault.patch
mm-do_fault-extract-to-call-vm_ops-do_fault-to-separate-function.patch
mm-introduce-do_read_fault.patch
mm-introduce-do_cow_fault.patch
mm-introduce-do_shared_fault-and-drop-do_fault.patch
mm-introduce-do_shared_fault-and-drop-do_fault-fix.patch
mm-introduce-do_shared_fault-and-drop-do_fault-fix-fix.patch
mm-consolidate-code-to-call-vm_ops-page_mkwrite.patch
mm-consolidate-code-to-call-vm_ops-page_mkwrite-fix.patch
mm-consolidate-code-to-setup-pte.patch
do_shared_fault-check-that-mmap_sem-is-held.patch
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