diff options
Diffstat (limited to 'include/linux/mm.h')
| -rw-r--r-- | include/linux/mm.h | 14 |
1 files changed, 12 insertions, 2 deletions
diff --git a/include/linux/mm.h b/include/linux/mm.h index f28f46eade6..03ab3e58f51 100644 --- a/include/linux/mm.h +++ b/include/linux/mm.h @@ -399,8 +399,18 @@ static inline void compound_unlock_irqrestore(struct page *page, static inline struct page *compound_head(struct page *page) { - if (unlikely(PageTail(page))) - return page->first_page; + if (unlikely(PageTail(page))) { + struct page *head = page->first_page; + + /* + * page->first_page may be a dangling pointer to an old + * compound page, so recheck that it is still a tail + * page before returning. + */ + smp_rmb(); + if (likely(PageTail(page))) + return head; + } return page; } |