diff options
| author | Naoya Horiguchi <n-horiguchi@ah.jp.nec.com> | 2015-02-11 15:25:28 -0800 |
|---|---|---|
| committer | Jiri Slaby <jslaby@suse.cz> | 2015-03-12 11:09:57 +0100 |
| commit | ea47f0342b5cdfd3dfbce2a8b85a9d82a0614ef2 (patch) | |
| tree | f57b2ca4e8c0918852d5f5307494a06fbcc4c6c8 /mm | |
| parent | c272044a55e2df31b31952149f71294615d7e1c3 (diff) | |
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>
Signed-off-by: Jiri Slaby <jslaby@suse.cz>
Diffstat (limited to 'mm')
| -rw-r--r-- | mm/hugetlb.c | 19 |
1 files changed, 18 insertions, 1 deletions
diff --git a/mm/hugetlb.c b/mm/hugetlb.c index 0b46aedef779..723e63aefb64 100644 --- a/mm/hugetlb.c +++ b/mm/hugetlb.c @@ -3175,7 +3175,24 @@ unsigned long hugetlb_change_protection(struct vm_area_struct *vma, pages++; 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); + pages++; + } + continue; + } + if (!huge_pte_none(pte)) { pte = huge_ptep_get_and_clear(mm, address, ptep); pte = pte_mkhuge(huge_pte_modify(pte, newprot)); pte = arch_make_huge_pte(pte, vma, NULL, 0); |