diff --git a/drivers/block/null_blk/zoned.c b/drivers/block/null_blk/zoned.c
index 174d93a84137..e41ec5096a63 100644
--- a/drivers/block/null_blk/zoned.c
+++ b/drivers/block/null_blk/zoned.c
@@ -13,6 +13,8 @@ static inline sector_t mb_to_sects(unsigned long mb)
 
 static inline unsigned int null_zone_no(struct nullb_device *dev, sector_t sect)
 {
+	if (WARN_ON_ONCE(!dev->zone_size_sects))
+		return 0;
 	return sect >> ilog2(dev->zone_size_sects);
 }
 
@@ -62,8 +64,8 @@ int null_init_zoned_dev(struct nullb_device *dev, struct request_queue *q)
 	sector_t sector = 0;
 	unsigned int i;
 
-	if (!is_power_of_2(dev->zone_size)) {
-		pr_err("zone_size must be power-of-two\n");
+	if (!dev->zone_size || !is_power_of_2(dev->zone_size)) {
+		pr_err("zone_size must be non-zero power-of-two\n");
 		return -EINVAL;
 	}
 	if (dev->zone_size > dev->size) {
@@ -94,6 +96,10 @@ int null_init_zoned_dev(struct nullb_device *dev, struct request_queue *q)
 	zone_capacity_sects = mb_to_sects(dev->zone_capacity);
 	dev_capacity_sects = mb_to_sects(dev->size);
 	dev->zone_size_sects = mb_to_sects(dev->zone_size);
+	if (!dev->zone_size_sects) {
+		pr_err("zone_size too large or too small, leads to zero sectors\n");
+		return -EINVAL;
+	}
 	dev->nr_zones = round_up(dev_capacity_sects, dev->zone_size_sects)
 		>> ilog2(dev->zone_size_sects);