diff --git a/block/ioctl.c b/block/ioctl.c
index 4476e0e85d1..4a85096f541 100644
--- a/block/ioctl.c
+++ b/block/ioctl.c
@@ -41,7 +41,7 @@ static int blkpg_ioctl(struct block_device *bdev, struct blkpg_ioctl_arg __user
 			    sizeof(long long) > sizeof(long)) {
 				long pstart = start, plength = length;
 				if (pstart != start || plength != length
-				    || pstart < 0 || plength < 0)
+				    || pstart < 0 || plength < 0 || partno > 65535)
 					return -EINVAL;
 			}