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| author | Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com> | 2013-05-24 15:55:21 -0700 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2013-06-07 12:46:37 -0700 |
| commit | 2f28357cd8f0be2c507d3a7d6f79c0cca0d7f9ce (patch) | |
| tree | 0154209c10d4f6d0f32b09cd62226227633e2e09 | |
| parent | 77809457d14ff89ac8e67f3cdf45a43b2b620f82 (diff) | |
| download | lwn-2f28357cd8f0be2c507d3a7d6f79c0cca0d7f9ce.tar.gz lwn-2f28357cd8f0be2c507d3a7d6f79c0cca0d7f9ce.zip | |
mm/THP: use pmd_populate() to update the pmd with pgtable_t pointer
commit 7c3425123ddfdc5f48e7913ff59d908789712b18 upstream.
We should not use set_pmd_at to update pmd_t with pgtable_t pointer.
set_pmd_at is used to set pmd with huge pte entries and architectures
like ppc64, clear few flags from the pte when saving a new entry.
Without this change we observe bad pte errors like below on ppc64 with
THP enabled.
BUG: Bad page map in process ld mm=0xc000001ee39f4780 pte:7fc3f37848000001 pmd:c000001ec0000000
Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
Cc: Hugh Dickins <hughd@google.com>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Reviewed-by: Andrea Arcangeli <aarcange@redhat.com>
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>
| -rw-r--r-- | mm/huge_memory.c | 7 |
1 files changed, 6 insertions, 1 deletions
diff --git a/mm/huge_memory.c b/mm/huge_memory.c index a9ab45ec7d5e..983d2e116da7 100644 --- a/mm/huge_memory.c +++ b/mm/huge_memory.c @@ -1893,7 +1893,12 @@ static void collapse_huge_page(struct mm_struct *mm, pte_unmap(pte); spin_lock(&mm->page_table_lock); BUG_ON(!pmd_none(*pmd)); - set_pmd_at(mm, address, pmd, _pmd); + /* + * We can only use set_pmd_at when establishing + * hugepmds and never for establishing regular pmds that + * points to regular pagetables. Use pmd_populate for that + */ + pmd_populate(mm, pmd, pmd_pgtable(_pmd)); spin_unlock(&mm->page_table_lock); anon_vma_unlock(vma->anon_vma); goto out; |