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authorNaoya Horiguchi <naoya.horiguchi@nec.com>2021-12-24 21:12:45 -0800
committerLinus Torvalds <torvalds@linux-foundation.org>2021-12-25 12:20:55 -0800
commite37e7b0b3bd52ec4f8ab71b027bcec08f57f1b3b (patch)
tree01b196046df27a6f93f99b6e9df0d7d1d1e77f5f /mm/memory-failure.c
parent7e5b901e4609441fc6bb94701c4743b39b6c277e (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__page_handle_poison() is expected to be called to isolate the error in 4kB unit, but it's not called due to the outdated if-condition in memory_failure_hugetlb().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.c13
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;