diff --git a/glibc-2.X-drd.supp b/glibc-2.X-drd.supp
index 879ea5d..441e7a8 100644
--- a/glibc-2.X-drd.supp
+++ b/glibc-2.X-drd.supp
@@ -94,6 +94,11 @@
    fun:pthread_detach
 }
 {
+   drd-libpthread-pthread_once
+   drd:ConflictingAccess
+   fun:pthread_once
+}
+{
    drd-libpthread-pthread_cancel_init
    drd:ConflictingAccess
    fun:pthread_cancel_init