diff --git a/helper_thread.c b/helper_thread.c
index fed21d1d61..2440604c12 100644
--- a/helper_thread.c
+++ b/helper_thread.c
@@ -110,10 +110,12 @@ static void block_signals(void)
 	sigset_t sigmask;
 
 	int ret;
+	(void)ret; /* Suppress unused variable warning */
 
 	ret = pthread_sigmask(SIG_UNBLOCK, NULL, &sigmask);
 	assert(ret == 0);
 	ret = pthread_sigmask(SIG_BLOCK, &sigmask, NULL);
+	assert(ret == 0);
 #endif
 }