ACPICA: Debugger: Lock namespace for duration of a namespace dump

Prevents issues if the namespace is changing underneath the
debugger.  Especially temporary nodes, since the debugger displays
these also.

Signed-off-by: Bob Moore <robert.moore@intel.com>
Signed-off-by: Lin Ming <ming.m.lin@intel.com>
Reviewed-by: Rafael Wysocki <rjw@sisk.pl>
Signed-off-by: Len Brown <len.brown@intel.com>

drivers/acpi/acpica/nsdump.c

@@ -624,9 +624,22 @@ acpi_ns_dump_objects(acpi_object_type type,
 		     acpi_owner_id owner_id, acpi_handle start_handle)
 {
 	struct acpi_walk_info info;
+	acpi_status status;
 
 	ACPI_FUNCTION_ENTRY();
 
+	/*
+	 * Just lock the entire namespace for the duration of the dump.
+	 * We don't want any changes to the namespace during this time,
+	 * especially the temporary nodes since we are going to display
+	 * them also.
+	 */
+	status = acpi_ut_acquire_mutex(ACPI_MTX_NAMESPACE);
+	if (ACPI_FAILURE(status)) {
+		acpi_os_printf("Could not acquire namespace mutex\n");
+		return;
+	}
+
 	info.debug_level = ACPI_LV_TABLES;
 	info.owner_id = owner_id;
 	info.display_type = display_type;
@@ -636,6 +649,8 @@ acpi_ns_dump_objects(acpi_object_type type,
 				     ACPI_NS_WALK_TEMP_NODES,
 				     acpi_ns_dump_one_object, NULL,
 				     (void *)&info, NULL);
+
+	(void)acpi_ut_release_mutex(ACPI_MTX_NAMESPACE);
 }
 #endif				/* ACPI_FUTURE_USAGE */