diff options
| author | Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com> | 2013-05-24 15:55:21 -0700 |
|---|---|---|
| committer | Ben Hutchings <ben@decadent.org.uk> | 2013-05-30 14:35:06 +0100 |
| commit | f45f28f4921a03d20d04f273dad68d30736304c6 (patch) | |
| tree | 00e03991febd0df110ed55d53719fa2c9b1b1dd9 /mm | |
| parent | 7fa32acca588177bbc49dc2b4c6fa469c4aa5bd5 (diff) | |
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: Ben Hutchings <ben@decadent.org.uk>
Diffstat (limited to 'mm')
| -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 470cbb45410..d80ac4bb097 100644 --- a/mm/huge_memory.c +++ b/mm/huge_memory.c @@ -1937,7 +1937,12 @@ 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; |