diff --git a/share/man/man9/callout.9 b/share/man/man9/callout.9
index 29a099f59fc9..0392919b58ab 100644
--- a/share/man/man9/callout.9
+++ b/share/man/man9/callout.9
@@ -1,4 +1,4 @@
-.\"	$NetBSD: callout.9,v 1.28 2014/11/20 15:43:52 ozaki-r Exp $
+.\"	$NetBSD: callout.9,v 1.28.18.1 2020/01/21 11:21:52 martin Exp $
 .\"
 .\" Copyright (c) 2000, 2003, 2009 The NetBSD Foundation, Inc.
 .\" All rights reserved.
@@ -27,7 +27,7 @@
 .\" ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
 .\" POSSIBILITY OF SUCH DAMAGE.
 .\"
-.Dd November 21, 2014
+.Dd January 12, 2020
 .Dt CALLOUT 9
 .Os
 .Sh NAME
@@ -59,7 +59,7 @@
 .Ft bool
 .Fn "callout_stop" "callout_t *c"
 .Ft bool
-.Fn "callout_halt" "callout_t *c" "kmutex_t *interlock"
+.Fn "callout_halt" "callout_t *c" "void *interlock"
 .Ft bool
 .Fn "callout_pending" "callout_t *c"
 .Ft bool