diff --git a/[refs] b/[refs]
index 33ada937a83e..99cd6e8ab758 100644
--- a/[refs]
+++ b/[refs]
@@ -1,2 +1,2 @@
 ---
-refs/heads/master: 1f425994f96d85540d47eee98daabc1e211b454e
+refs/heads/master: dd56a8e36f91f63c0a31e8a118d87b7cf01526b8
diff --git a/trunk/drivers/acpi/acpi_memhotplug.c b/trunk/drivers/acpi/acpi_memhotplug.c
index 3721f8dd0de3..5652569b3762 100644
--- a/trunk/drivers/acpi/acpi_memhotplug.c
+++ b/trunk/drivers/acpi/acpi_memhotplug.c
@@ -234,6 +234,17 @@ static int acpi_memory_enable_device(struct acpi_memory_device *mem_device)
 	 * (i.e. memory-hot-remove function)
 	 */
 	list_for_each_entry(info, &mem_device->res_list, list) {
+		u64 start_pfn, end_pfn;
+
+		start_pfn = info->start_addr >> PAGE_SHIFT;
+		end_pfn = (info->start_addr + info->length - 1) >> PAGE_SHIFT;
+
+		if (pfn_valid(start_pfn) || pfn_valid(end_pfn)) {
+			/* already enabled. try next area */
+			num_enabled++;
+			continue;
+		}
+
 		result = add_memory(info->start_addr, info->length);
 		if (result)
 			continue;