On 28/02/18 13:23, Jason Andryuk wrote:

A toolstack may delete the vif frontend and backend xenstore entries
while xen-netfront is in the removal code path.  In that case, the
checks for xenbus_read_driver_state would return XenbusStateUnknown, and
xennet_remove would hang indefinitely.  This hang prevents system
shutdown.

xennet_remove must be able to handle XenbusStateUnknown, and
netback_changed must also wake up the wake_queue for that state as well.

Fixes: 5b5971df3bc2 ("xen-netfront: remove warning when unloading module")

Signed-off-by: Jason Andryuk <redacted>
Cc: Eduardo Otubo <redacted>

Committed to xen/tip for-linus-4.16a


Juergen