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mm: hwpoison: call shake_page() after try_to_unmap() for mlocked page 

Memory error handler calls try_to_unmap() for error pages in various
states.  If the error page is a mlocked page, error handling could fail
with "still referenced by 1 users" message.  This is because the page is
linked to and stays in lru cache after the following call chain.

  try_to_unmap_one
    page_remove_rmap
      clear_page_mlock
        putback_lru_page
          lru_cache_add

memory_failure() calls shake_page() to hanlde the similar issue, but
current code doesn't cover because shake_page() is called only before
try_to_unmap().  So this patches adds shake_page().

Fixes: 23a003bfd2 ("mm/madvise: pass return code of memory_failure() to userspace")
Link: http://lkml.kernel.org/r/20170417055948.GM31394@yexl-desktop
Link: http://lkml.kernel.org/r/1493197841-23986-3-git-send-email-n-horiguchi@ah.jp.nec.com
Signed-off-by: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com>
Reported-by: kernel test robot <lkp@intel.com>
Cc: Xiaolong Ye <xiaolong.ye@intel.com>
Cc: Chen Gong <gong.chen@linux.intel.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
This commit is contained in:
Naoya Horiguchi 2017-05-03 14:56:22 -07:00 committed by Linus Torvalds
parent 8bcb74de76
commit 286c469a98
1 changed files with 8 additions and 0 deletions
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8
mm/memory-failure.c
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@ -916,6 +916,7 @@ static bool hwpoison_user_mappings(struct page *p, unsigned long pfn,
bool unmap_success;
int kill = 1, forcekill;
struct page *hpage = *hpagep;
bool mlocked = PageMlocked(hpage);
/*
* Here we are interested only in user-mapped pages, so skip any
@ -979,6 +980,13 @@ static bool hwpoison_user_mappings(struct page *p, unsigned long pfn,
pr_err("Memory failure: %#lx: failed to unmap page (mapcount=%d)\n",
pfn, page_mapcount(hpage));
/*
* try_to_unmap() might put mlocked page in lru cache, so call
* shake_page() again to ensure that it's flushed.
*/
if (mlocked)
shake_page(hpage, 0);
/*
* Now that the dirty bit has been propagated to the
* struct page and all unmaps done we can decide if