diff --git a/man2/prctl.2 b/man2/prctl.2
index 6de443938..7e78fc3c1 100644
--- a/man2/prctl.2
+++ b/man2/prctl.2
@@ -1586,7 +1586,8 @@ is an invalid address.
 .B EINVAL
 The value of
 .I option
-is not recognized.
+is not recognized,
+or not supported on this system.
 .TP
 .B EINVAL
 .I option