diff --git a/src/tools.c b/src/tools.c
index 4507564bc..1615ef2ae 100644
--- a/src/tools.c
+++ b/src/tools.c
@@ -4689,6 +4689,8 @@ char *indent_msg(char **out, int level)
 
 	needed = 1 + level * (lf + 1) + len + 1;
 	p = ret = malloc(needed);
+	if (unlikely(!ret))
+		return NULL;
 	in = *out;
 
 	/* skip initial LFs */