diff --git a/gdb/ChangeLog b/gdb/ChangeLog
index 4d75eeaee2..1d511ac516 100644
--- a/gdb/ChangeLog
+++ b/gdb/ChangeLog
@@ -1,3 +1,10 @@
+2015-12-17  Yao Qi  <yao.qi@linaro.org>
+
+	* aarch64-tdep.c (struct stack_item_t): Update comments.
+	(pass_on_stack): Set item.data to NULL.
+	(aarch64_push_dummy_call): Call write_memory if si->data
+	isn't NULL.
+
 2015-12-16  Pedro Alves  <palves@redhat.com>
 
 	* configure.ac (compiler warning flags): When testing a
diff --git a/gdb/aarch64-tdep.c b/gdb/aarch64-tdep.c
index 2d1df03e19..f4763bb4f9 100644
--- a/gdb/aarch64-tdep.c
+++ b/gdb/aarch64-tdep.c
@@ -855,7 +855,8 @@ aarch64_dwarf2_frame_init_reg (struct gdbarch *gdbarch, int regnum,
 
 typedef struct
 {
-  /* Value to pass on stack.  */
+  /* Value to pass on stack.  It can be NULL if this item is for stack
+     padding.  */
   const gdb_byte *data;
 
   /* Size in bytes of value to pass on stack.  */
@@ -1124,7 +1125,7 @@ pass_on_stack (struct aarch64_call_info *info, struct type *type,
       int pad = align - (info->nsaa & (align - 1));
 
       item.len = pad;
-      item.data = buf;
+      item.data = NULL;
 
       VEC_safe_push (stack_item_t, info->si, &item);
       info->nsaa += pad;
@@ -1382,7 +1383,8 @@ aarch64_push_dummy_call (struct gdbarch *gdbarch, struct value *function,
       stack_item_t *si = VEC_last (stack_item_t, info.si);
 
       sp -= si->len;
-      write_memory (sp, si->data, si->len);
+      if (si->data != NULL)
+	write_memory (sp, si->data, si->len);
       VEC_pop (stack_item_t, info.si);
     }