diff --git a/include/linux/cgroup.h b/include/linux/cgroup.h
index c2ad120281e84542c1d644ec7cae85cb82c6ac6a..8d326442cda310d5b1b65226c3c7658995220a9e 100644
--- a/include/linux/cgroup.h
+++ b/include/linux/cgroup.h
@@ -575,6 +575,8 @@ static inline struct cftype *of_cft(struct kernfs_open_file *of)
 }
 
 struct cgroup_subsys_state *of_css(struct kernfs_open_file *of);
+struct cgroup *cgroup_kn_lock_live(struct kernfs_node *kn, bool drain_offline);
+void cgroup_kn_unlock(struct kernfs_node *kn);
 
 /* cft/css accessors for cftype->seq_*() operations */
 static inline struct cftype *seq_cft(struct seq_file *seq)
diff --git a/kernel/cgroup/cgroup-internal.h b/kernel/cgroup/cgroup-internal.h
index 9d4a477bbd37ca1b717149026a3c7a46f7b2ca52..dcd116f04174ab7468afdb3dd4d427d1d6c3a9b9 100644
--- a/kernel/cgroup/cgroup-internal.h
+++ b/kernel/cgroup/cgroup-internal.h
@@ -227,8 +227,6 @@ struct cgroup *kn_priv(struct kernfs_node *kn);
 struct cgroup_root *cgroup_root_from_kf(struct kernfs_root *kf_root);
 struct cgroup *task_cgroup_from_root(struct task_struct *task,
 				     struct cgroup_root *root);
-struct cgroup *cgroup_kn_lock_live(struct kernfs_node *kn, bool drain_offline);
-void cgroup_kn_unlock(struct kernfs_node *kn);
 int cgroup_path_ns_locked(struct cgroup *cgrp, char *buf, size_t buflen,
 			  struct cgroup_namespace *ns);
 
diff --git a/mm/memcontrol.c b/mm/memcontrol.c
index 55bbddf61cfc0fd1598a8b88665e41191239d9c6..e59d3816316271a3bcb1a95f2aed4dba51e44de5 100644
--- a/mm/memcontrol.c
+++ b/mm/memcontrol.c
@@ -5277,12 +5277,14 @@ static ssize_t memory_wmark_scale_factor_write(struct kernfs_open_file *of,
  * wmark_min_adj:  A -10, B -25, C 0, D 50, E -25, F 50
  * wmark_min_eadj: A -10, B -10, C 0, D 50, E -10, F 50
  */
-static void memcg_update_wmark_min_adj(struct mem_cgroup *memcg, int val)
+static void memcg_update_wmark_min_adj_locked(struct mem_cgroup *memcg,
+					      int val)
 {
 	struct mem_cgroup *p;
 	struct mem_cgroup *iter;
 
-	mutex_lock(&cgroup_mutex);
+	lockdep_assert_held(&cgroup_mutex);
+
 	memcg->wmark_min_adj = val;
 	/* update hierarchical wmark_min_eadj, pre-order iteration */
 	for_each_mem_cgroup_tree(iter, memcg) {
@@ -5294,7 +5296,6 @@ static void memcg_update_wmark_min_adj(struct mem_cgroup *memcg, int val)
 			val = p->wmark_min_eadj;
 		iter->wmark_min_eadj = val;
 	}
-	mutex_unlock(&cgroup_mutex);
 }
 
 static int memory_wmark_min_adj_show(struct seq_file *m, void *v)
@@ -5310,7 +5311,8 @@ static int memory_wmark_min_adj_show(struct seq_file *m, void *v)
 static ssize_t memory_wmark_min_adj_write(struct kernfs_open_file *of,
 				char *buf, size_t nbytes, loff_t off)
 {
-	struct mem_cgroup *memcg = mem_cgroup_from_css(of_css(of));
+	struct cgroup *cgrp;
+	struct mem_cgroup *memcg;
 	int ret, wmark_min_adj;
 
 	buf = strstrip(buf);
@@ -5321,8 +5323,14 @@ static ssize_t memory_wmark_min_adj_write(struct kernfs_open_file *of,
 	if (wmark_min_adj < -25 || wmark_min_adj > 50)
 		return -EINVAL;
 
-	memcg_update_wmark_min_adj(memcg, wmark_min_adj);
+	cgrp = cgroup_kn_lock_live(of->kn, false);
+	if (!cgrp)
+		return -ENODEV;
+
+	memcg = mem_cgroup_from_css(of_css(of));
+	memcg_update_wmark_min_adj_locked(memcg, wmark_min_adj);
 
+	cgroup_kn_unlock(of->kn);
 	return nbytes;
 }