Index: share/man/man9/contigmalloc.9
===================================================================
--- share/man/man9/contigmalloc.9
+++ share/man/man9/contigmalloc.9
@@ -25,7 +25,7 @@
 .\"
 .\" $FreeBSD$
 .\"
-.Dd July 19, 2007
+.Dd January 29, 2015
 .Dt CONTIGMALLOC 9
 .Os
 .Sh NAME
@@ -100,6 +100,12 @@
 .Dv M_NOWAIT
 is specified, it may select a page for reclamation that must first be
 written to backing storage, causing it to sleep.
+.Pp
+Note that unlike
+.Xr free 9 ,
+.Dv NULL
+may not be passed as the address to
+.Fn contigfree .
 .Sh RETURN VALUES
 The
 .Fn contigmalloc