diff --git a/sys/conf/kern.pre.mk b/sys/conf/kern.pre.mk
index dbb16c8ddf5..ee74a9e8283 100644
--- a/sys/conf/kern.pre.mk
+++ b/sys/conf/kern.pre.mk
@@ -25,6 +25,7 @@ COPTFLAGS?=	-O
 .else
 . if defined(DEBUG)
 _MINUS_O=	-O
+CTFFLAGS+=	-g
 . else
 _MINUS_O=	-O2
 . endif