diff --git a/index-pack.c b/index-pack.c
index cf81a99..b405864 100644
--- a/index-pack.c
+++ b/index-pack.c
@@ -753,7 +753,7 @@
 		  const char *keep_name, const char *keep_msg,
 		  unsigned char *sha1)
 {
-	char *report = "pack";
+	const char *report = "pack";
 	char name[PATH_MAX];
 	int err;