1 files changed, 4 insertions, 2 deletions

diff --git a/kernel/cgroup.c b/kernel/cgroup.c
index a220fdb66568..469dd547770c 100644
--- a/kernel/cgroup.c
+++ b/kernel/cgroup.c
@@ -4196,7 +4196,9 @@ static void *cgroup_pidlist_next(struct seq_file *s, void *v, loff_t *pos)
 
 static int cgroup_pidlist_show(struct seq_file *s, void *v)
 {
-        return seq_printf(s, "%d\n", *(int *)v);
+        seq_printf(s, "%d\n", *(int *)v);
+
+        return 0;
 }
 
 static u64 cgroup_read_notify_on_release(struct cgroup_subsys_state *css,
@@ -5451,7 +5453,7 @@ struct cgroup_subsys_state *css_tryget_online_from_dir(struct dentry *dentry,
 struct cgroup_subsys_state *css_from_id(int id, struct cgroup_subsys *ss)
 {
         WARN_ON_ONCE(!rcu_read_lock_held());
-        return idr_find(&ss->css_idr, id);
+        return id > 0 ? idr_find(&ss->css_idr, id) : NULL;
 }
 
 #ifdef CONFIG_CGROUP_DEBUG