xen/blkfront: allow xenbus state transition to Closing->Closed when not Connected
This situation can occur when attempting to attach a block device whose
backend is an empty physical CD-ROM driver. The backend in this case
will go directly from the Initialising state to Closing->Closed.
Previously this would result in a NULL pointer deref on info->gd
(xenbus_dev_fatal does not return as a1a15ac5 seems to expect)
Cc: stable@kernel.org
Signed-off-by: Ian Campbell <ian.campbell@citrix.com>
Acked-by: Jeremy Fitzhardinge <jeremy.fitzhardinge@citrix.com>
Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
diff --git a/drivers/block/xen-blkfront.c b/drivers/block/xen-blkfront.c
index 8f90508..6971a12 100644
--- a/drivers/block/xen-blkfront.c
+++ b/drivers/block/xen-blkfront.c
@@ -977,8 +977,10 @@
break;
case XenbusStateClosing:
- if (info->gd == NULL)
- xenbus_dev_fatal(dev, -ENODEV, "gd is NULL");
+ if (info->gd == NULL) {
+ xenbus_frontend_closed(dev);
+ break;
+ }
bd = bdget_disk(info->gd, 0);
if (bd == NULL)
xenbus_dev_fatal(dev, -ENODEV, "bdget failed");