diff --git a/[refs] b/[refs]
index 8183bc6004da..88fcd8421eab 100644
--- a/[refs]
+++ b/[refs]
@@ -1,2 +1,2 @@
 ---
-refs/heads/master: a734bcc812146cfba530e1adaf609fce1357982e
+refs/heads/master: ef009b25f4f8a77d2b32067d424d5ac757dcdc5b
diff --git a/trunk/mm/hugetlb.c b/trunk/mm/hugetlb.c
index 2c551b28ba69..49e693b7fd0c 100644
--- a/trunk/mm/hugetlb.c
+++ b/trunk/mm/hugetlb.c
@@ -2349,6 +2349,9 @@ static int unmap_ref_private(struct mm_struct *mm, struct vm_area_struct *vma,
 
 /*
  * Hugetlb_cow() should be called with page lock of the original hugepage held.
+ * Called with hugetlb_instantiation_mutex held and pte_page locked so we
+ * cannot race with other handlers or page migration.
+ * Keep the pte_same checks anyway to make transition from the mutex easier.
  */
 static int hugetlb_cow(struct mm_struct *mm, struct vm_area_struct *vma,
 			unsigned long address, pte_t *ptep, pte_t pte,