• Naoya Horiguchi's avatar
    mm/memory-failure: call shake_page() when error hits thp tail page · 09789e5d
    Naoya Horiguchi authored
    Currently memory_failure() calls shake_page() to sweep pages out from
    pcplists only when the victim page is 4kB LRU page or thp head page.
    But we should do this for a thp tail page too.
    
    Consider that a memory error hits a thp tail page whose head page is on
    a pcplist when memory_failure() runs.  Then, the current kernel skips
    shake_pages() part, so hwpoison_user_mappings() returns without calling
    split_huge_page() nor try_to_unmap() because PageLRU of the thp head is
    still cleared due to the skip of shake_page().
    
    As a result, me_huge_page() runs for the thp, which is broken behavior.
    
    One effect is a leak of the thp.  And another is to fail to isolate the
    memory error, so later access to the error address causes another MCE,
    which kills the processes which used the thp.
    
    This patch fixes this problem by calling shake_page() for thp tail case.
    
    Fixes: 385de357 ("thp: allow a hwpoisoned head page to be put back to LRU")
    Signed-off-by: default avatarNaoya Horiguchi <n-horiguchi@ah.jp.nec.com>
    Reviewed-by: default avatarAndi Kleen <ak@linux.intel.com>
    Acked-by: default avatarDean Nelson <dnelson@redhat.com>
    Cc: Andrea Arcangeli <aarcange@redhat.com>
    Cc: Hidetoshi Seto <seto.hidetoshi@jp.fujitsu.com>
    Cc: Jin Dongming <jin.dongming@np.css.fujitsu.com>
    Cc: <stable@vger.kernel.org>	[3.4+]
    Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
    Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
    09789e5d
memory-failure.c 49.2 KB