diff --git a/Documentation/ABI/testing/sysfs-bus-event_source-devices-format b/Documentation/ABI/testing/sysfs-bus-event_source-devices-format
index 079afc71363d..77f47ff5ee02 100644
--- a/Documentation/ABI/testing/sysfs-bus-event_source-devices-format
+++ b/Documentation/ABI/testing/sysfs-bus-event_source-devices-format
@@ -9,6 +9,12 @@ Description:
 		we want to export, so that userspace can deal with sane
 		name/value pairs.
 
+		Userspace must be prepared for the possibility that attributes
+		define overlapping bit ranges. For example:
+			attr1 = 'config:0-23'
+			attr2 = 'config:0-7'
+			attr3 = 'config:12-35'
+
 		Example: 'config1:1,6-10,44'
 		Defines contents of attribute that occupies bits 1,6-10,44 of
 		perf_event_attr::config1.