diff --git a/drivers/s390/cio/ccwgroup.c b/drivers/s390/cio/ccwgroup.c
index e0ce65fca4e797..9a50f245774b04 100644
--- a/drivers/s390/cio/ccwgroup.c
+++ b/drivers/s390/cio/ccwgroup.c
@@ -113,7 +113,8 @@ ccwgroup_release (struct device *dev)
 
 	for (i = 0; i < gdev->count; i++) {
 		if (gdev->cdev[i]) {
-			dev_set_drvdata(&gdev->cdev[i]->dev, NULL);
+			if (dev_get_drvdata(&gdev->cdev[i]->dev) == gdev)
+				dev_set_drvdata(&gdev->cdev[i]->dev, NULL);
 			put_device(&gdev->cdev[i]->dev);
 		}
 	}
@@ -296,6 +297,7 @@ int ccwgroup_create_from_string(struct device *root, unsigned int creator_id,
 			if (dev_get_drvdata(&gdev->cdev[i]->dev) == gdev)
 				dev_set_drvdata(&gdev->cdev[i]->dev, NULL);
 			put_device(&gdev->cdev[i]->dev);
+			gdev->cdev[i] = NULL;
 		}
 	mutex_unlock(&gdev->reg_mutex);
 	put_device(&gdev->dev);
diff --git a/drivers/s390/cio/cio.c b/drivers/s390/cio/cio.c
index 5954b905e3cab9..326f4cc7f92c93 100644
--- a/drivers/s390/cio/cio.c
+++ b/drivers/s390/cio/cio.c
@@ -174,6 +174,7 @@ cio_start_key (struct subchannel *sch,	/* subchannel structure */
 	CIO_TRACE_EVENT(4, sch->dev.bus_id);
 
 	orb = &to_io_private(sch)->orb;
+	memset(orb, 0, sizeof(union orb));
 	/* sch is always under 2G. */
 	orb->cmd.intparm = (u32)(addr_t)sch;
 	orb->cmd.fmt = 1;