diff --git a/kernel/cgroup.c b/kernel/cgroup.c
index 62f1a5231fe9..2727f9238359 100644
--- a/kernel/cgroup.c
+++ b/kernel/cgroup.c
@@ -2569,6 +2569,7 @@ static int proc_cgroup_show(struct seq_file *m, void *v)
 		/* Skip this hierarchy if it has no active subsystems */
 		if (!root->actual_subsys_bits)
 			continue;
+		seq_printf(m, "%lu:", root->subsys_bits);
 		for_each_subsys(root, ss)
 			seq_printf(m, "%s%s", count++ ? "," : "", ss->name);
 		seq_putc(m, ':');