Index: share/man/man3/queue.3
===================================================================
--- share/man/man3/queue.3
+++ share/man/man3/queue.3
@@ -28,10 +28,12 @@
 .\"	@(#)queue.3	8.2 (Berkeley) 1/24/94
 .\" $FreeBSD$
 .\"
-.Dd June 24, 2015
+.Dd October 22, 2015
 .Dt QUEUE 3
 .Os
 .Sh NAME
+.Nm queue(3)
+\(em
 .Nm SLIST_CLASS_ENTRY ,
 .Nm SLIST_CLASS_HEAD ,
 .Nm SLIST_EMPTY ,
@@ -1244,6 +1246,47 @@
 }
 TAILQ_INIT(&head);
 .Ed
+.Sh DIAGNOSTICS
+In the kernel (with
+.Va INVARIANTS
+enabled), a number of other macros are available for debugging
+.Nm :
+.Bl -hang -offset indent
+.It Fn QMD_LIST_CHECK_HEAD "LIST_HEAD *head" "LIST_ENTRY NAME"
+.Pp
+If the list is non-empty, validates that the first element of the list points
+back at
+.Fa head .
+.It Fn QMD_LIST_CHECK_NEXT "TYPE *elm" "LIST_ENTRY NAME"
+.Pp
+If an element follows
+.Fa elm
+in the list, validates that the next element points back at
+.Fa elm .
+.It Fn QMD_LIST_CHECK_PREV "TYPE *elm" "LIST_ENTRY NAME"
+.Pp
+Validates that the previous element (or head of the list) points to
+.Fa elm .
+.It Fn QMD_TAILQ_CHECK_HEAD "TAILQ_HEAD *head" "TAILQ_ENTRY NAME"
+.Pp
+If the tailq is non-empty, validates that the first element of the tailq points
+back at
+.Fa head .
+.It Fn QMD_TAILQ_CHECK_TAIL "TAILQ_HEAD *head" "TAILQ_ENTRY NAME"
+.Pp
+Validates that the tail of the tailq is a pointer to pointer to
+.Va NULL .
+.It Fn QMD_TAILQ_CHECK_NEXT "TYPE *elm" "TAILQ_ENTRY NAME"
+.Pp
+If an element follows
+.Fa elm
+in the tailq, validates that the next element points back at
+.Fa elm .
+.It Fn QMD_TAILQ_CHECK_PREV "TYPE *elm" "TAILQ_ENTRY NAME"
+.Pp
+Validates that the previous element (or head of the tailq) points to
+.Fa elm .
+.El
 .Sh SEE ALSO
 .Xr tree 3
 .Sh HISTORY