diff --git a/drivers/block/null_blk_main.c b/drivers/block/null_blk_main.c
index bd6e5cd02a57..53d4c1529984 100644
--- a/drivers/block/null_blk_main.c
+++ b/drivers/block/null_blk_main.c
@@ -141,7 +141,7 @@ static int g_bs = 512;
 module_param_named(bs, g_bs, int, 0444);
 MODULE_PARM_DESC(bs, "Block size (in bytes)");
 
-static int nr_devices = 1;
+static unsigned int nr_devices = 1;
 module_param(nr_devices, int, 0444);
 MODULE_PARM_DESC(nr_devices, "Number of devices to register");
 
@@ -1767,6 +1767,10 @@ static int __init null_init(void)
 		pr_err("null_blk: legacy IO path no longer available\n");
 		return -EINVAL;
 	}
+	if (!nr_devices) {
+		pr_err("null_blk: invalid number of devices\n");
+		return -EINVAL;
+	}
 	if (g_queue_mode == NULL_Q_MQ && g_use_per_node_hctx) {
 		if (g_submit_queues != nr_online_nodes) {
 			pr_warn("null_blk: submit_queues param is set to %u.\n",