--- x/fs/kernfs/file.c
+++ y/fs/kernfs/file.c
@@ -756,6 +756,7 @@ static void kernfs_release_file(struct k
 	lockdep_assert_held(kernfs_open_file_mutex_ptr(kn));
 
 	if (!of->released) {
+		mutex_lock(&of->mutex);
 		/*
 		 * A file is never detached without being released and we
 		 * need to be able to release files which are deactivated
@@ -764,6 +765,7 @@ static void kernfs_release_file(struct k
 		kn->attr.ops->release(of);
 		of->released = true;
 		of_on(of)->nr_to_release--;
+		mutex_unlock(&of->mutex);
 	}
 }