diff --git a/drivers/xen/pvcalls-front.c b/drivers/xen/pvcalls-front.c
index 40caa92bff33..d1e1d8d2b9d5 100644
--- a/drivers/xen/pvcalls-front.c
+++ b/drivers/xen/pvcalls-front.c
@@ -1103,7 +1103,7 @@ static int pvcalls_front_remove(struct xenbus_device *dev)
 			kfree(map);
 		}
 	}
-	if (bedata->ref >= 0)
+	if (bedata->ref != -1)
 		gnttab_end_foreign_access(bedata->ref, 0, 0);
 	kfree(bedata->ring.sring);
 	kfree(bedata);
@@ -1128,6 +1128,8 @@ static int pvcalls_front_probe(struct xenbus_device *dev,
 	}
 
 	versions = xenbus_read(XBT_NIL, dev->otherend, "versions", &len);
+	if (IS_ERR(versions))
+		return PTR_ERR(versions);
 	if (!len)
 		return -EINVAL;
 	if (strcmp(versions, "1")) {