diff --git a/library/psa_crypto.c b/library/psa_crypto.c
index e6d3851..e3b2be6 100644
--- a/library/psa_crypto.c
+++ b/library/psa_crypto.c
@@ -936,7 +936,7 @@
 
 error:
     *p_slot = NULL;
-    psa_unregister_read(slot);
+    psa_unregister_read_under_mutex(slot);
 
     return status;
 }
@@ -968,7 +968,7 @@
     }
 
     if (psa_key_lifetime_is_external((*p_slot)->attr.lifetime)) {
-        psa_unregister_read(*p_slot);
+        psa_unregister_read_under_mutex(*p_slot);
         *p_slot = NULL;
         return PSA_ERROR_NOT_SUPPORTED;
     }