diff --git a/cache/classes/loaders.php b/cache/classes/loaders.php
index ebc23edd367..3893e92e864 100644
--- a/cache/classes/loaders.php
+++ b/cache/classes/loaders.php
@@ -621,11 +621,11 @@ class cache implements cache_loader {
         // store; parent method will have set it to all stores if needed.
         if ($setaftervalidation) {
             $lock = false;
+            try {
                 if (!empty($this->requirelockingbeforewrite) && !$this->check_lock_state($key)) {
                     $this->acquire_lock($key);
                     $lock = true;
                 }
-            try {
                 if ($requiredversion === self::VERSION_NONE) {
                     $this->set_implementation($key, self::VERSION_NONE, $result, false);
                 } else {
@@ -744,11 +744,11 @@ class cache implements cache_loader {
                 foreach ($resultmissing as $key => $value) {
                     $result[$keysparsed[$key]] = $value;
                     $lock = false;
+                    try {
                         if (!empty($this->requirelockingbeforewrite)) {
                             $this->acquire_lock($key);
                             $lock = true;
                         }
-                    try {
                         if ($value !== false) {
                             $this->set($key, $value);
                         }
@@ -1683,8 +1683,12 @@ class cache_application extends cache implements cache_loader_with_locking {
      * @throws moodle_exception If the lock cannot be obtained
      */
     public function acquire_lock($key) {
+        $releaseparent = false;
+        try {
             if ($this->get_loader() !== false) {
                 $this->get_loader()->acquire_lock($key);
+                // If something goes wrong we should release the parent.
+                $releaseparent = true;
             }
             $key = cache_helper::hash_key($key, $this->get_definition());
             $before = microtime(true);
@@ -1701,11 +1705,18 @@ class cache_application extends cache implements cache_loader_with_locking {
                     \core\lock\timing_wrapper_lock_factory::record_lock_data($after, $before,
                         $this->get_definition()->get_id(), $key, $lock, $this->get_identifier() . $key);
                 }
+                $releaseparent = false;
                 return true;
             } else {
                 throw new moodle_exception('ex_unabletolock', 'cache', '', null,
                     'store: ' . get_class($this->get_store()) . ', lock: ' . $key);
             }
+        } finally {
+            // Release the parent lock if we acquired it, then threw an exception.
+            if ($releaseparent) {
+                $this->get_loader()->release_lock($key);
+            }
+        }
     }
 
     /**