ACPICA: Report error if method creates 2 objects with the same name

Fixed a regression where an error was no
longer emitted if a control method attempts to create 2
objects of the same name. This previously and now returns
AE_ALREADY_EXISTS. When this exception occurs, it invokes
the mechanism that will dynamically serialize the control
method to possible prevent future errors. (BZ 440)
Signed-off-by: Alexey Starikovskiy <alexey.y.starikovskiy@intel.com>
Signed-off-by: Len Brown <len.brown@intel.com>

drivers/acpi/dispatcher/dswload.c

@@ -547,6 +547,7 @@ acpi_ds_load2_begin_op(struct acpi_walk_state *walk_state,
 	acpi_status status;
 	acpi_object_type object_type;
 	char *buffer_ptr;
+	u32 flags;
 
 	ACPI_FUNCTION_TRACE(ds_load2_begin_op);
 
@@ -752,12 +753,20 @@ acpi_ds_load2_begin_op(struct acpi_walk_state *walk_state,
 			break;
 		}
 
-		/* Add new entry into namespace */
+		flags = ACPI_NS_NO_UPSEARCH;
+		if (walk_state->pass_number == 3) {
+
+			/* Execution mode, node cannot already exist */
+
+			flags |= ACPI_NS_ERROR_IF_FOUND;
+		}
+
+		/* Add new entry or lookup existing entry */
 
 		status =
 		    acpi_ns_lookup(walk_state->scope_info, buffer_ptr,
-				   object_type, ACPI_IMODE_LOAD_PASS2,
-				   ACPI_NS_NO_UPSEARCH, walk_state, &(node));
+				   object_type, ACPI_IMODE_LOAD_PASS2, flags,
+				   walk_state, &node);
 		break;
 	}
 

drivers/acpi/parser/psparse.c

@@ -540,6 +540,11 @@ acpi_status acpi_ps_parse_aml(struct acpi_walk_state *walk_state)
 
 			if ((status == AE_ALREADY_EXISTS) &&
 			    (!walk_state->method_desc->method.mutex)) {
+				ACPI_INFO((AE_INFO,
+					   "Marking method %4.4s as Serialized",
+					   walk_state->method_node->name.
+					   ascii));
+
 				/*
 				 * Method tried to create an object twice. The probable cause is
 				 * that the method cannot handle reentrancy.