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| author | Konstantin Khlebnikov <koct9i@gmail.com> | 2016-04-28 16:18:32 -0700 |
|---|---|---|
| committer | Ben Hutchings <ben@decadent.org.uk> | 2016-06-15 21:28:13 +0100 |
| commit | d0ad87609746a7646fbe7c93c21cb472f2dbbf87 (patch) | |
| tree | 0699f595a8b74e32f52091240dc1640a45cfd19d | |
| parent | 60477461b5c6bc501bd72e58e6d783a1a253d63f (diff) | |
| download | linux-stable-d0ad87609746a7646fbe7c93c21cb472f2dbbf87.tar.gz linux-stable-d0ad87609746a7646fbe7c93c21cb472f2dbbf87.tar.bz2 linux-stable-d0ad87609746a7646fbe7c93c21cb472f2dbbf87.zip | |
mm/huge_memory: replace VM_NO_THP VM_BUG_ON with actual VMA check
commit 3486b85a29c1741db99d0c522211c82d2b7a56d0 upstream.
Khugepaged detects own VMAs by checking vm_file and vm_ops but this way
it cannot distinguish private /dev/zero mappings from other special
mappings like /dev/hpet which has no vm_ops and popultes PTEs in mmap.
This fixes false-positive VM_BUG_ON and prevents installing THP where
they are not expected.
Link: http://lkml.kernel.org/r/CACT4Y+ZmuZMV5CjSFOeXviwQdABAgT7T+StKfTqan9YDtgEi5g@mail.gmail.com
Fixes: 78f11a255749 ("mm: thp: fix /dev/zero MAP_PRIVATE and vm_flags cleanups")
Signed-off-by: Konstantin Khlebnikov <koct9i@gmail.com>
Reported-by: Dmitry Vyukov <dvyukov@google.com>
Acked-by: Vlastimil Babka <vbabka@suse.cz>
Acked-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Cc: Dmitry Vyukov <dvyukov@google.com>
Cc: Andrea Arcangeli <aarcange@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
[bwh: Backported to 3.2:
- The assertions use VM_BUG_ON() and also check is_linear_pfn_mapping();
keep that check
- Adjust context]
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>
| -rw-r--r-- | mm/huge_memory.c | 8 |
1 files changed, 4 insertions, 4 deletions
diff --git a/mm/huge_memory.c b/mm/huge_memory.c index d570aaeb2579..2fde51669cd9 100644 --- a/mm/huge_memory.c +++ b/mm/huge_memory.c @@ -1635,14 +1635,14 @@ int khugepaged_enter_vma_merge(struct vm_area_struct *vma, * page fault if needed. */ return 0; - if (vma->vm_ops) + if (vma->vm_ops || (vm_flags & VM_NO_THP)) /* khugepaged not yet working on file or special mappings */ return 0; /* * If is_pfn_mapping() is true is_learn_pfn_mapping() must be * true too, verify it here. */ - VM_BUG_ON(is_linear_pfn_mapping(vma) || vm_flags & VM_NO_THP); + VM_BUG_ON(is_linear_pfn_mapping(vma)); hstart = (vma->vm_start + ~HPAGE_PMD_MASK) & HPAGE_PMD_MASK; hend = vma->vm_end & HPAGE_PMD_MASK; if (hstart < hend) @@ -1831,8 +1831,8 @@ static bool hugepage_vma_check(struct vm_area_struct *vma) * If is_pfn_mapping() is true is_learn_pfn_mapping() must be * true too, verify it here. */ - VM_BUG_ON(is_linear_pfn_mapping(vma) || vma->vm_flags & VM_NO_THP); - return true; + VM_BUG_ON(is_linear_pfn_mapping(vma)); + return !(vma->vm_flags & VM_NO_THP); } static void collapse_huge_page(struct mm_struct *mm, |