diff --git a/test/test_arena.c b/test/test_arena.c
index a94d7a0..8b47fc7 100644
--- a/test/test_arena.c
+++ b/test/test_arena.c
@@ -115,7 +115,7 @@ int main()
         pid_t p;
         switch (p = fork()) {
         case -1: /* error */
-            perror(fork());
+            perror("fork()");
             exit(EXIT_FAILURE);
 
         case 0: /* child */