diff --git a/drivers/gpu/drm/drm_bridge.c b/drivers/gpu/drm/drm_bridge.c
index 86e9c49232f7..986e4c79a4e0 100644
--- a/drivers/gpu/drm/drm_bridge.c
+++ b/drivers/gpu/drm/drm_bridge.c
@@ -867,6 +867,7 @@ void drm_atomic_bridge_chain_post_disable(struct drm_bridge *bridge,
 
 	encoder = bridge->encoder;
 
+	mutex_lock(&encoder->bridge_chain_mutex);
 	list_for_each_entry_from(bridge, &encoder->bridge_chain, chain_node) {
 		limit = NULL;
 
@@ -915,6 +916,7 @@ void drm_atomic_bridge_chain_post_disable(struct drm_bridge *bridge,
 			/* Jump all bridges that we have already post_disabled */
 			bridge = limit;
 	}
+	mutex_unlock(&encoder->bridge_chain_mutex);
 }
 EXPORT_SYMBOL(drm_atomic_bridge_chain_post_disable);
 
@@ -961,6 +963,7 @@ void drm_atomic_bridge_chain_pre_enable(struct drm_bridge *bridge,
 
 	encoder = bridge->encoder;
 
+	mutex_lock(&encoder->bridge_chain_mutex);
 	list_for_each_entry_reverse(iter, &encoder->bridge_chain, chain_node) {
 		if (iter->pre_enable_prev_first) {
 			next = iter;
@@ -1003,6 +1006,7 @@ void drm_atomic_bridge_chain_pre_enable(struct drm_bridge *bridge,
 		if (iter == bridge)
 			break;
 	}
+	mutex_unlock(&encoder->bridge_chain_mutex);
 }
 EXPORT_SYMBOL(drm_atomic_bridge_chain_pre_enable);