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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 21:29:28 +0100 |
| commit | 1ec1d7466f9f21b243e0f96c47a3bcace44b993d (patch) | |
| tree | 20c79b81449c653216fc45d8cc011c8f2857b84d /mm/huge_memory.c | |
| parent | f4b592cb05dce29cd4c6778400ece68a45a1a223 (diff) | |
| download | linux-stable-1ec1d7466f9f21b243e0f96c47a3bcace44b993d.tar.gz linux-stable-1ec1d7466f9f21b243e0f96c47a3bcace44b993d.tar.bz2 linux-stable-1ec1d7466f9f21b243e0f96c47a3bcace44b993d.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 3.16: deleted assertions used VM_BUG_ON()]
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>
Diffstat (limited to 'mm/huge_memory.c')
| -rw-r--r-- | mm/huge_memory.c | 6 |
1 files changed, 2 insertions, 4 deletions
diff --git a/mm/huge_memory.c b/mm/huge_memory.c index 479b57cc5195..dc528a51ccbf 100644 --- a/mm/huge_memory.c +++ b/mm/huge_memory.c @@ -2068,10 +2068,9 @@ 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; - VM_BUG_ON(vm_flags & VM_NO_THP); hstart = (vma->vm_start + ~HPAGE_PMD_MASK) & HPAGE_PMD_MASK; hend = vma->vm_end & HPAGE_PMD_MASK; if (hstart < hend) @@ -2376,8 +2375,7 @@ static bool hugepage_vma_check(struct vm_area_struct *vma) return false; if (is_vma_temporary_stack(vma)) return false; - VM_BUG_ON(vma->vm_flags & VM_NO_THP); - return true; + return !(vma->vm_flags & VM_NO_THP); } static void collapse_huge_page(struct mm_struct *mm, |