diff --git a/arch/sim/src/sim/up_simsmp.c b/arch/sim/src/sim/up_simsmp.c
index 22f68a5f80..68c8469cb9 100644
--- a/arch/sim/src/sim/up_simsmp.c
+++ b/arch/sim/src/sim/up_simsmp.c
@@ -270,7 +270,7 @@ void sim_cpu0_start(void)
   sigemptyset(&set);
   sigaddset(&set, SIGUSR1);
 
-  ret = sigprocmask(SIG_UNBLOCK, &set, NULL);
+  ret = pthread_sigmask(SIG_UNBLOCK, &set, NULL);
   if (ret < 0)
     {
       return;