diff --git a/[refs] b/[refs]
index 23bc5e7c2538..8b4d54e6e7fd 100644
--- a/[refs]
+++ b/[refs]
@@ -1,2 +1,2 @@
 ---
-refs/heads/master: f5754bfd107b08edddaf871d676ec6fe0792d07a
+refs/heads/master: 722d0172377a5697919b9f7e5beb95165b1dec4e
diff --git a/trunk/kernel/futex.c b/trunk/kernel/futex.c
index fb65e822fc41..d73ef1f3e55d 100644
--- a/trunk/kernel/futex.c
+++ b/trunk/kernel/futex.c
@@ -304,8 +304,14 @@ void put_futex_key(int fshared, union futex_key *key)
  */
 static int fault_in_user_writeable(u32 __user *uaddr)
 {
-	int ret = get_user_pages(current, current->mm, (unsigned long)uaddr,
-				 1, 1, 0, NULL, NULL);
+	struct mm_struct *mm = current->mm;
+	int ret;
+
+	down_read(&mm->mmap_sem);
+	ret = get_user_pages(current, mm, (unsigned long)uaddr,
+			     1, 1, 0, NULL, NULL);
+	up_read(&mm->mmap_sem);
+
 	return ret < 0 ? ret : 0;
 }