diff --git a/sys/netinet6/in6_src.c b/sys/netinet6/in6_src.c
index 3093f6f8427e..0508db24f4de 100644
--- a/sys/netinet6/in6_src.c
+++ b/sys/netinet6/in6_src.c
@@ -141,14 +141,20 @@ static struct in6_addrpolicy *match_addrsel_policy(struct sockaddr_in6 *);
 	if ((r) < sizeof(ip6stat.ip6s_sources_rule) / \
 		sizeof(ip6stat.ip6s_sources_rule[0])) /* check for safety */ \
 		ip6stat.ip6s_sources_rule[(r)]++; \
-	/* printf("in6_selectsrc: replace %s with %s by %d\n", ia_best ? ip6_sprintf(&ia_best->ia_addr.sin6_addr) : "none", ip6_sprintf(&ia->ia_addr.sin6_addr), (r)); */ \
+	/* { \
+	char ip6buf[INET6_ADDRSTRLEN], ip6b[INET6_ADDRSTRLEN]; \
+	printf("in6_selectsrc: replace %s with %s by %d\n", ia_best ? ip6_sprintf(ip6buf, &ia_best->ia_addr.sin6_addr) : "none", ip6_sprintf(ip6b, &ia->ia_addr.sin6_addr), (r)); \
+	} */ \
 	goto replace; \
 } while(0)
 #define NEXT(r) do {\
 	if ((r) < sizeof(ip6stat.ip6s_sources_rule) / \
 		sizeof(ip6stat.ip6s_sources_rule[0])) /* check for safety */ \
 		ip6stat.ip6s_sources_rule[(r)]++; \
-	/* printf("in6_selectsrc: keep %s against %s by %d\n", ia_best ? ip6_sprintf(&ia_best->ia_addr.sin6_addr) : "none", ip6_sprintf(&ia->ia_addr.sin6_addr), (r)); */ \
+	/* { \
+	char ip6buf[INET6_ADDRSTRLEN], ip6b[INET6_ADDRSTRLEN]; \
+	printf("in6_selectsrc: keep %s against %s by %d\n", ia_best ? ip6_sprintf(ip6buf, &ia_best->ia_addr.sin6_addr) : "none", ip6_sprintf(ip6b, &ia->ia_addr.sin6_addr), (r)); \
+	} */ \
 	goto next;		/* XXX: we can't use 'continue' here */ \
 } while(0)
 #define BREAK(r) do { \