releases/4.19.31/mm-hwpoison-fix-thp-split-handing-in-soft_offline_in_use_page.patch

   1 From 46612b751c4941c5c0472ddf04027e877ae5990f Mon Sep 17 00:00:00 2001
   2 From: zhongjiang <zhongjiang@huawei.com>
   3 Date: Tue, 5 Mar 2019 15:41:16 -0800
   4 Subject: mm: hwpoison: fix thp split handing in soft_offline_in_use_page()
   5
   6 From: zhongjiang <zhongjiang@huawei.com>
   7
   8 commit 46612b751c4941c5c0472ddf04027e877ae5990f upstream.
   9
  10 When soft_offline_in_use_page() runs on a thp tail page after pmd is
  11 split, we trigger the following VM_BUG_ON_PAGE():
  12
  13   Memory failure: 0x3755ff: non anonymous thp
  14   __get_any_page: 0x3755ff: unknown zero refcount page type 2fffff80000000
  15   Soft offlining pfn 0x34d805 at process virtual address 0x20fff000
  16   page:ffffea000d360140 count:0 mapcount:0 mapping:0000000000000000 index:0x1
  17   flags: 0x2fffff80000000()
  18   raw: 002fffff80000000 ffffea000d360108 ffffea000d360188 0000000000000000
  19   raw: 0000000000000001 0000000000000000 00000000ffffffff 0000000000000000
  20   page dumped because: VM_BUG_ON_PAGE(page_ref_count(page) == 0)
  21   ------------[ cut here ]------------
  22   kernel BUG at ./include/linux/mm.h:519!
  23
  24 soft_offline_in_use_page() passed refcount and page lock from tail page
  25 to head page, which is not needed because we can pass any subpage to
  26 split_huge_page().
  27
  28 Naoya had fixed a similar issue in c3901e722b29 ("mm: hwpoison: fix thp
  29 split handling in memory_failure()").  But he missed fixing soft
  30 offline.
  31
  32 Link: http://lkml.kernel.org/r/1551452476-24000-1-git-send-email-zhongjiang@huawei.com
  33 Fixes: 61f5d698cc97 ("mm: re-enable THP")
  34 Signed-off-by: zhongjiang <zhongjiang@huawei.com>
  35 Acked-by: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com>
  36 Cc: Michal Hocko <mhocko@suse.com>
  37 Cc: Hugh Dickins <hughd@google.com>
  38 Cc: Kirill A. Shutemov <kirill@shutemov.name>
  39 Cc: Andrea Arcangeli <aarcange@redhat.com>
  40 Cc: <stable@vger.kernel.org>    [4.5+]
  41 Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
  42 Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
  43 Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
  44
  45 ---
  46  mm/memory-failure.c |   14 ++++++--------
  47  1 file changed, 6 insertions(+), 8 deletions(-)
  48
  49 --- a/mm/memory-failure.c
  50 +++ b/mm/memory-failure.c
  51 @@ -1823,19 +1823,17 @@ static int soft_offline_in_use_page(stru
  52         struct page *hpage = compound_head(page);
  53
  54         if (!PageHuge(page) && PageTransHuge(hpage)) {
  55 -               lock_page(hpage);
  56 -               if (!PageAnon(hpage) || unlikely(split_huge_page(hpage))) {
  57 -                       unlock_page(hpage);
  58 -                       if (!PageAnon(hpage))
  59 +               lock_page(page);
  60 +               if (!PageAnon(page) || unlikely(split_huge_page(page))) {
  61 +                       unlock_page(page);
  62 +                       if (!PageAnon(page))
  63                                 pr_info("soft offline: %#lx: non anonymous thp\n", page_to_pfn(page));
  64                         else
  65                                 pr_info("soft offline: %#lx: thp split failed\n", page_to_pfn(page));
  66 -                       put_hwpoison_page(hpage);
  67 +                       put_hwpoison_page(page);
  68                         return -EBUSY;
  69                 }
  70 -               unlock_page(hpage);
  71 -               get_hwpoison_page(page);
  72 -               put_hwpoison_page(hpage);
  73 +               unlock_page(page);
  74         }
  75
  76         /*