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author | Naoya Horiguchi <n-horiguchi@ah.jp.nec.com> | 2015-02-11 15:25:28 -0800 |
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committer | Ben Hutchings <ben@decadent.org.uk> | 2015-05-09 23:16:16 +0100 |
commit | 9e725572445374fe05d80478f4c4ff9631f9a59c (patch) | |
tree | 4633f759dfb3edf606bfeb64d49999cd1c1530f2 | |
parent | 20f19d910265c9232d7f8ce80496c56948d0fe01 (diff) | |
download | kernel_samsung_smdk4412-9e725572445374fe05d80478f4c4ff9631f9a59c.zip kernel_samsung_smdk4412-9e725572445374fe05d80478f4c4ff9631f9a59c.tar.gz kernel_samsung_smdk4412-9e725572445374fe05d80478f4c4ff9631f9a59c.tar.bz2 |
mm/hugetlb: add migration/hwpoisoned entry check in hugetlb_change_protection
commit a8bda28d87c38c6aa93de28ba5d30cc18e865a11 upstream.
There is a race condition between hugepage migration and
change_protection(), where hugetlb_change_protection() doesn't care about
migration entries and wrongly overwrites them. That causes unexpected
results like kernel crash. HWPoison entries also can cause the same
problem.
This patch adds is_hugetlb_entry_(migration|hwpoisoned) check in this
function to do proper actions.
Fixes: 290408d4a2 ("hugetlb: hugepage migration core")
Signed-off-by: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com>
Cc: Hugh Dickins <hughd@google.com>
Cc: James Hogan <james.hogan@imgtec.com>
Cc: David Rientjes <rientjes@google.com>
Cc: Mel Gorman <mel@csn.ul.ie>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Michal Hocko <mhocko@suse.cz>
Cc: Rik van Riel <riel@redhat.com>
Cc: Andrea Arcangeli <aarcange@redhat.com>
Cc: Luiz Capitulino <lcapitulino@redhat.com>
Cc: Nishanth Aravamudan <nacc@linux.vnet.ibm.com>
Cc: Lee Schermerhorn <lee.schermerhorn@hp.com>
Cc: Steve Capper <steve.capper@linaro.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
[bwh: Backported to 3.2:
- Adjust context
- We don't have split page table locks, so don't unlock inside the loop
- We don't count pages here]
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>
-rw-r--r-- | mm/hugetlb.c | 17 |
1 files changed, 16 insertions, 1 deletions
diff --git a/mm/hugetlb.c b/mm/hugetlb.c index f6a621b..dcc6780 100644 --- a/mm/hugetlb.c +++ b/mm/hugetlb.c @@ -3037,7 +3037,22 @@ void hugetlb_change_protection(struct vm_area_struct *vma, continue; if (huge_pmd_unshare(mm, &address, ptep)) continue; - if (!huge_pte_none(huge_ptep_get(ptep))) { + pte = huge_ptep_get(ptep); + if (unlikely(is_hugetlb_entry_hwpoisoned(pte))) + continue; + if (unlikely(is_hugetlb_entry_migration(pte))) { + swp_entry_t entry = pte_to_swp_entry(pte); + + if (is_write_migration_entry(entry)) { + pte_t newpte; + + make_migration_entry_read(&entry); + newpte = swp_entry_to_pte(entry); + set_huge_pte_at(mm, address, ptep, newpte); + } + continue; + } + if (!huge_pte_none(pte)) { pte = huge_ptep_get_and_clear(mm, address, ptep); pte = pte_mkhuge(pte_modify(pte, newprot)); set_huge_pte_at(mm, address, ptep, pte); |