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| author | Naoya Horiguchi <naoya.horiguchi@nec.com> | 2021-12-25 08:12:45 +0300 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2021-12-29 14:28:58 +0300 |
| commit | 7a77e22fde6349d276f862a521d190ad932e711d (patch) | |
| tree | 43acb1cded5108b695f962ec7739d6f89a3101ad /mm | |
| parent | 6b2cdcc8f5552615c7bdfc0ba3fa45a5d0d15680 (diff) | |
| download | linux-7a77e22fde6349d276f862a521d190ad932e711d.tar.xz | |
mm, hwpoison: fix condition in free hugetlb page path
commit e37e7b0b3bd52ec4f8ab71b027bcec08f57f1b3b upstream.
When a memory error hits a tail page of a free hugepage,
__page_handle_poison() is expected to be called to isolate the error in
4kB unit, but it's not called due to the outdated if-condition in
memory_failure_hugetlb(). This loses the chance to isolate the error in
the finer unit, so it's not optimal. Drop the condition.
This "(p != head && TestSetPageHWPoison(head)" condition is based on the
old semantics of PageHWPoison on hugepage (where PG_hwpoison flag was
set on the subpage), so it's not necessray any more. By getting to set
PG_hwpoison on head page for hugepages, concurrent error events on
different subpages in a single hugepage can be prevented by
TestSetPageHWPoison(head) at the beginning of memory_failure_hugetlb().
So dropping the condition should not reopen the race window originally
mentioned in commit b985194c8c0a ("hwpoison, hugetlb:
lock_page/unlock_page does not match for handling a free hugepage")
[naoya.horiguchi@linux.dev: fix "HardwareCorrupted" counter]
Link: https://lkml.kernel.org/r/20211220084851.GA1460264@u2004
Link: https://lkml.kernel.org/r/20211210110208.879740-1-naoya.horiguchi@linux.dev
Signed-off-by: Naoya Horiguchi <naoya.horiguchi@nec.com>
Reported-by: Fei Luo <luofei@unicloud.com>
Reviewed-by: Mike Kravetz <mike.kravetz@oracle.com>
Cc: <stable@vger.kernel.org> [5.14+]
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Diffstat (limited to 'mm')
| -rw-r--r-- | mm/memory-failure.c | 13 |
1 files changed, 4 insertions, 9 deletions
diff --git a/mm/memory-failure.c b/mm/memory-failure.c index bdbbb32211a5..b47f19af8e59 100644 --- a/mm/memory-failure.c +++ b/mm/memory-failure.c @@ -1437,17 +1437,12 @@ static int memory_failure_hugetlb(unsigned long pfn, int flags) if (!(flags & MF_COUNT_INCREASED)) { res = get_hwpoison_page(p, flags); if (!res) { - /* - * Check "filter hit" and "race with other subpage." - */ lock_page(head); - if (PageHWPoison(head)) { - if ((hwpoison_filter(p) && TestClearPageHWPoison(p)) - || (p != head && TestSetPageHWPoison(head))) { + if (hwpoison_filter(p)) { + if (TestClearPageHWPoison(head)) num_poisoned_pages_dec(); - unlock_page(head); - return 0; - } + unlock_page(head); + return 0; } unlock_page(head); res = MF_FAILED; |