diff --git a/drivers/char/mem.c b/drivers/char/mem.c
index 1c596b5cdb27..d8e3b547e0ae 100644
--- a/drivers/char/mem.c
+++ b/drivers/char/mem.c
@@ -702,8 +702,8 @@ static const struct memdev {
 #endif
 	 [5] = { "zero", 0666, &zero_fops, 0 },
 	 [7] = { "full", 0666, &full_fops, 0 },
-	 [8] = { "random", 0666, &random_fops, 0 },
-	 [9] = { "urandom", 0666, &urandom_fops, 0 },
+	 [8] = { "random", 0666, &random_fops, FMODE_NOWAIT },
+	 [9] = { "urandom", 0666, &urandom_fops, FMODE_NOWAIT },
 #ifdef CONFIG_PRINTK
 	[11] = { "kmsg", 0644, &kmsg_fops, 0 },
 #endif
diff --git a/drivers/char/random.c b/drivers/char/random.c
index 7bd6eb15d432..50dc861f183b 100644
--- a/drivers/char/random.c
+++ b/drivers/char/random.c
@@ -1298,6 +1298,11 @@ static ssize_t random_read_iter(struct kiocb *kiocb, struct iov_iter *iter)
 {
 	int ret;
 
+	if (!crng_ready() &&
+	    ((kiocb->ki_flags & (IOCB_NOWAIT | IOCB_NOIO)) ||
+	     (kiocb->ki_filp->f_flags & O_NONBLOCK)))
+		return -EAGAIN;
+
 	ret = wait_for_random_bytes();
 	if (ret != 0)
 		return ret;