diff --git a/test/flush.c b/test/flush.c
index fed5311..e442751 100644
--- a/test/flush.c
+++ b/test/flush.c
@@ -22,6 +22,7 @@
 #include <stddef.h>
 #include <stdio.h>
 #include <unistd.h>
+#include <sys/syscall.h>
 #include <sys/types.h>
 #include <linux/limits.h>
 #include <limits.h>