diff --git a/arch/um/drivers/random.c b/arch/um/drivers/random.c
index 73b2bdd6d2d3b867165e116b7a1b430f34096c9b..e942e836f9954335651fc3c2b6587c2bd7d7e888 100644
--- a/arch/um/drivers/random.c
+++ b/arch/um/drivers/random.c
@@ -78,6 +78,7 @@ static const struct file_operations rng_chrdev_ops = {
 	.read		= rng_dev_read,
 };
 
+/* rng_init shouldn't be called more than once at boot time */
 static struct miscdevice rng_miscdev = {
 	RNG_MISCDEV_MINOR,
 	RNG_MODULE_NAME,