diff --git a/commit.h b/commit.h
index f3d2f57a89..99b9e78209 100644
--- a/commit.h
+++ b/commit.h
@@ -30,7 +30,7 @@ extern const char *commit_type;
 struct name_decoration {
 	struct name_decoration *next;
 	int type;
-	char name[1];
+	char name[FLEX_ARRAY];
 };
 
 enum decoration_type {
diff --git a/log-tree.c b/log-tree.c
index 2adf82ba02..de760db1a6 100644
--- a/log-tree.c
+++ b/log-tree.c
@@ -77,7 +77,7 @@ int parse_decorate_color_config(const char *var, const int ofs, const char *valu
 void add_name_decoration(enum decoration_type type, const char *name, struct object *obj)
 {
 	int nlen = strlen(name);
-	struct name_decoration *res = xmalloc(sizeof(struct name_decoration) + nlen);
+	struct name_decoration *res = xmalloc(sizeof(*res) + nlen + 1);
 	memcpy(res->name, name, nlen + 1);
 	res->type = type;
 	res->next = add_decoration(&name_decoration, obj, res);