From: Zi Yan <ziy@xxxxxxxxxx>
Since the order of a PUD THP is greater than MAX_ORDER, do not consider
its tail pages corrupted. Also print sub_compound_mapcount when dumping
a PMDPageInPUD.
Signed-off-by: Zi Yan <ziy@xxxxxxxxxx>
---
mm/debug.c | 6 +++++-
1 file changed, 5 insertions(+), 1 deletion(-)
diff --git a/mm/debug.c b/mm/debug.c
index ccca576b2899..f5b035dc620d 100644
--- a/mm/debug.c
+++ b/mm/debug.c
@@ -68,7 +68,9 @@ void __dump_page(struct page *page, const char *reason)
goto hex_only;
}
- if (page < head || (page >= head + MAX_ORDER_NR_PAGES)) {
+ if (page < head ||
+ (page >= head + max_t(unsigned long, compound_nr(head),
+ (unsigned long)MAX_ORDER_NR_PAGES))) {
/*
* Corrupt page, so we cannot call page_mapping. Instead, do a
* safe subset of the steps that page_mapping() does. Caution:
@@ -109,6 +111,8 @@ void __dump_page(struct page *page, const char *reason)
head, compound_order(head),
head_compound_mapcount(head));
}
+ if (compound_order(head) == HPAGE_PUD_ORDER && PMDPageInPUD(page))
+ pr_warn("sub_compound_mapcount:%d\n", sub_compound_mapcount(page));
}
if (PageKsm(page))
type = "ksm ";
--
2.28.0
