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-rw-r--r--mm/hugetlb.c1
-rw-r--r--mm/memory-failure.c33
2 files changed, 33 insertions, 1 deletions
diff --git a/mm/hugetlb.c b/mm/hugetlb.c
index 636be5d..7123270 100644
--- a/mm/hugetlb.c
+++ b/mm/hugetlb.c
@@ -2974,6 +2974,7 @@ int dequeue_hwpoisoned_huge_page(struct page *hpage)
spin_lock(&hugetlb_lock);
if (is_hugepage_on_freelist(hpage)) {
list_del(&hpage->lru);
+ set_page_refcounted(hpage);
h->free_huge_pages--;
h->free_huge_pages_node[nid]--;
ret = 0;
diff --git a/mm/memory-failure.c b/mm/memory-failure.c
index 5c7158a..333f87d 100644
--- a/mm/memory-failure.c
+++ b/mm/memory-failure.c
@@ -983,7 +983,10 @@ int __memory_failure(unsigned long pfn, int trapno, int flags)
* We need/can do nothing about count=0 pages.
* 1) it's a free page, and therefore in safe hand:
* prep_new_page() will be the gate keeper.
- * 2) it's part of a non-compound high order page.
+ * 2) it's a free hugepage, which is also safe:
+ * an affected hugepage will be dequeued from hugepage freelist,
+ * so there's no concern about reusing it ever after.
+ * 3) it's part of a non-compound high order page.
* Implies some kernel user: cannot stop them from
* R/W the page; let's pray that the page has been
* used and will be freed some time later.
@@ -995,6 +998,24 @@ int __memory_failure(unsigned long pfn, int trapno, int flags)
if (is_free_buddy_page(p)) {
action_result(pfn, "free buddy", DELAYED);
return 0;
+ } else if (PageHuge(hpage)) {
+ /*
+ * Check "just unpoisoned", "filter hit", and
+ * "race with other subpage."
+ */
+ lock_page_nosync(hpage);
+ if (!PageHWPoison(hpage)
+ || (hwpoison_filter(p) && TestClearPageHWPoison(p))
+ || (p != hpage && TestSetPageHWPoison(hpage))) {
+ atomic_long_sub(nr_pages, &mce_bad_pages);
+ return 0;
+ }
+ set_page_hwpoison_huge_page(hpage);
+ res = dequeue_hwpoisoned_huge_page(hpage);
+ action_result(pfn, "free huge",
+ res ? IGNORED : DELAYED);
+ unlock_page(hpage);
+ return res;
} else {
action_result(pfn, "high order kernel", IGNORED);
return -EBUSY;
@@ -1156,6 +1177,16 @@ int unpoison_memory(unsigned long pfn)
nr_pages = 1 << compound_order(page);
if (!get_page_unless_zero(page)) {
+ /*
+ * Since HWPoisoned hugepage should have non-zero refcount,
+ * race between memory failure and unpoison seems to happen.
+ * In such case unpoison fails and memory failure runs
+ * to the end.
+ */
+ if (PageHuge(page)) {
+ pr_debug("MCE: Memory failure is now running on free hugepage %#lx\n", pfn);
+ return 0;
+ }
if (TestClearPageHWPoison(p))
atomic_long_sub(nr_pages, &mce_bad_pages);
pr_debug("MCE: Software-unpoisoned free page %#lx\n", pfn);
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