Index: head/share/man/man9/vm_map_protect.9
===================================================================
--- head/share/man/man9/vm_map_protect.9
+++ head/share/man/man9/vm_map_protect.9
@@ -96,6 +96,11 @@
 for an entry within the range,
 .Dv KERN_PROTECTION_FAILURE
 is returned.
+If a copy-on-write mapping is transitioned from read-only to
+read-write, and too little swap space is available for backing the
+copied pages,
+.Dv KERN_RESOURCE_SHORTAGE
+is returned.
 .Sh SEE ALSO
 .Xr vm_map 9
 .Sh AUTHORS