diff --git a/src/sem/ntapi_sem_set.c b/src/sem/ntapi_sem_set.c
index ab42032..c7833fc 100644
--- a/src/sem/ntapi_sem_set.c
+++ b/src/sem/ntapi_sem_set.c
@@ -92,10 +92,10 @@ int32_t	__stdcall __ntapi_sem_set(
 		/* lock */
 		hlock = &(__ntapi_internals()->hlock);
 
-		if (at_locked_cas(hlock,0,1))
-			return __sem_set_return(
-				mapaddr,0,
-				NT_STATUS_RESOURCE_NOT_OWNED);
+		while (at_locked_cas(hlock,0,1))
+			__ntapi->zw_delay_execution(
+				NT_SYNC_NON_ALERTABLE,
+				&(nt_timeout){{0,0}});
 
 		/* data copy */
 		__ntapi->tt_generic_memcpy(