diff --git a/builtin/grep.c b/builtin/grep.c
index d85cbabea6..5ec4cecae4 100644
--- a/builtin/grep.c
+++ b/builtin/grep.c
@@ -285,8 +285,8 @@ static int wait_all(void)
 
 static int grep_cmd_config(const char *var, const char *value, void *cb)
 {
-	int st = grep_config(var, value, cb);
-	if (git_color_default_config(var, value, cb) < 0)
+	int st = grep_config(var, value, NULL);
+	if (git_color_default_config(var, value, NULL) < 0)
 		st = -1;
 
 	if (!strcmp(var, "grep.threads")) {