diff --git a/regressions/ck_bitmap/validate/serial.c b/regressions/ck_bitmap/validate/serial.c
index 9dbe8e6..79aca8d 100644
--- a/regressions/ck_bitmap/validate/serial.c
+++ b/regressions/ck_bitmap/validate/serial.c
@@ -157,7 +157,7 @@ test_init(bool init)
 }
 
 static ck_bitmap_t *
-random_init()
+random_init(void)
 {
 	ck_bitmap_t *bitmap;
 	unsigned int i;