diff options
| author | Naoya Horiguchi <naoya.horiguchi@nec.com> | 2021-12-24 21:12:45 -0800 |
|---|---|---|
| committer | Linus Torvalds <torvalds@linux-foundation.org> | 2021-12-25 12:20:55 -0800 |
| commit | e37e7b0b3bd52ec4f8ab71b027bcec08f57f1b3b (patch) | |
| tree | 01b196046df27a6f93f99b6e9df0d7d1d1e77f5f /mm/memory-failure.c | |
| parent | 7e5b901e4609441fc6bb94701c4743b39b6c277e (diff) | |
mm, hwpoison: fix condition in free hugetlb page path
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4kB unit, but it's not called due to the outdated if-condition in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>
Diffstat (limited to 'mm/memory-failure.c')
| -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 07c875fdeaf0..682828b94ab6 100644 --- a/mm/memory-failure.c +++ b/mm/memory-failure.c @@ -1470,17 +1470,12 @@ 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; |