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-rw-r--r--mm/memory-failure.c50
1 files changed, 45 insertions, 5 deletions
diff --git a/mm/memory-failure.c b/mm/memory-failure.c
index 17a8e3bc3b01..a810ab1519f0 100644
--- a/mm/memory-failure.c
+++ b/mm/memory-failure.c
@@ -915,6 +915,39 @@ static int page_action(struct page_state *ps, struct page *p,
return (result == RECOVERED || result == DELAYED) ? 0 : -EBUSY;
}
+/**
+ * get_hwpoison_page() - Get refcount for memory error handling:
+ * @page: raw error page (hit by memory error)
+ *
+ * Return: return 0 if failed to grab the refcount, otherwise true (some
+ * non-zero value.)
+ */
+int get_hwpoison_page(struct page *page)
+{
+ struct page *head = compound_head(page);
+
+ if (PageHuge(head))
+ return get_page_unless_zero(head);
+
+ /*
+ * Thp tail page has special refcounting rule (refcount of tail pages
+ * is stored in ->_mapcount,) so we can't call get_page_unless_zero()
+ * directly for tail pages.
+ */
+ if (PageTransHuge(head)) {
+ if (get_page_unless_zero(head)) {
+ if (PageTail(page))
+ get_page(page);
+ return 1;
+ } else {
+ return 0;
+ }
+ }
+
+ return get_page_unless_zero(page);
+}
+EXPORT_SYMBOL_GPL(get_hwpoison_page);
+
/*
* Do all that is necessary to remove user space mappings. Unmap
* the pages and send SIGBUS to the processes if the data was dirty.
@@ -1097,8 +1130,7 @@ int memory_failure(unsigned long pfn, int trapno, int flags)
* In fact it's dangerous to directly bump up page count from 0,
* that may make page_freeze_refs()/page_unfreeze_refs() mismatch.
*/
- if (!(flags & MF_COUNT_INCREASED) &&
- !get_page_unless_zero(hpage)) {
+ if (!(flags & MF_COUNT_INCREASED) && !get_hwpoison_page(p)) {
if (is_free_buddy_page(p)) {
action_result(pfn, MSG_BUDDY, DELAYED);
return 0;
@@ -1130,12 +1162,20 @@ int memory_failure(unsigned long pfn, int trapno, int flags)
if (!PageHuge(p) && PageTransHuge(hpage)) {
if (!PageAnon(hpage)) {
pr_err("MCE: %#lx: non anonymous thp\n", pfn);
+ if (TestClearPageHWPoison(p))
+ atomic_long_sub(nr_pages, &num_poisoned_pages);
put_page(p);
+ if (p != hpage)
+ put_page(hpage);
return -EBUSY;
}
if (unlikely(split_huge_page(hpage))) {
pr_err("MCE: %#lx: thp split failed\n", pfn);
+ if (TestClearPageHWPoison(p))
+ atomic_long_sub(nr_pages, &num_poisoned_pages);
put_page(p);
+ if (p != hpage)
+ put_page(hpage);
return -EBUSY;
}
VM_BUG_ON_PAGE(!page_count(p), p);
@@ -1413,12 +1453,12 @@ int unpoison_memory(unsigned long pfn)
*/
if (!PageHuge(page) && PageTransHuge(page)) {
pr_info("MCE: Memory failure is now running on %#lx\n", pfn);
- return 0;
+ return 0;
}
nr_pages = 1 << compound_order(page);
- if (!get_page_unless_zero(page)) {
+ if (!get_hwpoison_page(p)) {
/*
* Since HWPoisoned hugepage should have non-zero refcount,
* race between memory failure and unpoison seems to happen.
@@ -1486,7 +1526,7 @@ static int __get_any_page(struct page *p, unsigned long pfn, int flags)
* When the target page is a free hugepage, just remove it
* from free hugepage list.
*/
- if (!get_page_unless_zero(compound_head(p))) {
+ if (!get_hwpoison_page(p)) {
if (PageHuge(p)) {
pr_info("%s: %#lx free huge page\n", __func__, pfn);
ret = 0;