diff --git a/fs/char_dev.c b/fs/char_dev.c
index 44a240c..a112a47 100644
--- a/fs/char_dev.c
+++ b/fs/char_dev.c
@@ -134,6 +134,12 @@
 			ret = -EBUSY;
 			goto out;
 		}
+
+		if (new_min < old_min && new_max > old_max) {
+			ret = -EBUSY;
+			goto out;
+		}
+
 	}
 
 	cd->next = *cp;