diff --git a/generator.c b/generator.c
index 886d57b..b1ff7bd 100644
--- a/generator.c
+++ b/generator.c
@@ -279,7 +279,7 @@ int main(int argc, char *argv[])
 		exit(EXIT_FAILURE);
 	}
 
-	shared = mmap(NULL, sizeof(*shared), PROT_WRITE, MAP_SHARED, shmfd, 0);
+	shared = mmap(NULL, sizeof(*shared), PROT_READ | PROT_WRITE, MAP_SHARED, shmfd, 0);
 	if (shared == MAP_FAILED) {
 		perror(pname);
 		exit(EXIT_FAILURE);