diff --git a/thpool.c b/thpool.c
index db96848..71ddf90 100644
--- a/thpool.c
+++ b/thpool.c
@@ -341,7 +341,7 @@ static void* thread_do(struct thread* thread_p){
 	/* Register signal handler */
 	struct sigaction act;
 	sigemptyset(&act.sa_mask);
-	act.sa_flags = 0;
+	act.sa_flags = SA_ONSTACK;
 	act.sa_handler = thread_hold;
 	if (sigaction(SIGUSR1, &act, NULL) == -1) {
 		err("thread_do(): cannot handle SIGUSR1");