1 files changed, 15 insertions, 5 deletions

diff --git a/include/linux/mm.h b/include/linux/mm.h
index f28f46eade6a..c1b7414c7bef 100644
--- a/include/linux/mm.h
+++ b/include/linux/mm.h
@@ -175,7 +175,7 @@ extern unsigned int kobjsize(const void *objp);
  * Special vmas that are non-mergable, non-mlock()able.
  * Note: mm/huge_memory.c VM_NO_THP depends on this definition.
  */
-#define VM_SPECIAL (VM_IO | VM_DONTEXPAND | VM_PFNMAP)
+#define VM_SPECIAL (VM_IO | VM_DONTEXPAND | VM_PFNMAP | VM_MIXEDMAP)
 
 /*
  * mapping from the currently active vm_flags protection bits (the
@@ -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;
 }
 
@@ -757,7 +767,7 @@ static inline bool __cpupid_match_pid(pid_t task_pid, int cpupid)
 #ifdef LAST_CPUPID_NOT_IN_PAGE_FLAGS
 static inline int page_cpupid_xchg_last(struct page *page, int cpupid)
 {
-        return xchg(&page->_last_cpupid, cpupid);
+        return xchg(&page->_last_cpupid, cpupid & LAST_CPUPID_MASK);
 }
 
 static inline int page_cpupid_last(struct page *page)
@@ -766,7 +776,7 @@ static inline int page_cpupid_last(struct page *page)
 }
 static inline void page_cpupid_reset_last(struct page *page)
 {
-        page->_last_cpupid = -1;
+        page->_last_cpupid = -1 & LAST_CPUPID_MASK;
 }
 #else
 static inline int page_cpupid_last(struct page *page)