diff --git a/library/psa_crypto.c b/library/psa_crypto.c
index b16fac16fe..87444e129f 100644
--- a/library/psa_crypto.c
+++ b/library/psa_crypto.c
@@ -4687,7 +4687,7 @@ static psa_status_t psa_aead_setup(psa_aead_operation_t *operation,
     operation->key_type = psa_get_key_type(&attributes);
 
 exit:
-    unlock_status = psa_unregister_read(slot);
+    unlock_status = psa_unregister_read_under_mutex(slot);
 
     if (status == PSA_SUCCESS) {
         status = unlock_status;