diff --git a/builtin/fmt-merge-msg.c b/builtin/fmt-merge-msg.c
index a517f1794a..4ee6a88d75 100644
--- a/builtin/fmt-merge-msg.c
+++ b/builtin/fmt-merge-msg.c
@@ -230,7 +230,7 @@ static void add_branch_desc(struct strbuf *out, const char *name)
 static void record_person(int which, struct string_list *people,
 			  struct commit *commit)
 {
-	char name_buf[MAX_GITNAME], *name, *name_end;
+	char *name_buf, *name, *name_end;
 	struct string_list_item *elem;
 	const char *field = (which == 'a') ? "\nauthor " : "\ncommitter ";
 
@@ -243,10 +243,9 @@ static void record_person(int which, struct string_list *people,
 		name_end--;
 	while (isspace(*name_end) && name <= name_end)
 		name_end--;
-	if (name_end < name || name + MAX_GITNAME <= name_end)
+	if (name_end < name)
 		return;
-	memcpy(name_buf, name, name_end - name + 1);
-	name_buf[name_end - name + 1] = '\0';
+	name_buf = xmemdupz(name, name_end - name + 1);
 
 	elem = string_list_lookup(people, name_buf);
 	if (!elem) {
@@ -254,6 +253,7 @@ static void record_person(int which, struct string_list *people,
 		elem->util = (void *)0;
 	}
 	elem->util = (void*)(util_as_integral(elem) + 1);
+	free(name_buf);
 }
 
 static int cmp_string_list_util_as_integral(const void *a_, const void *b_)