提交 c2d2e673 编写于 作者: J Jason Andryuk 提交者: Juergen Gross

xen-netfront: Fix hang on device removal

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: 5b5971df ("xen-netfront: remove warning when unloading module")
Signed-off-by: NJason Andryuk <jandryuk@gmail.com>
Cc: Eduardo Otubo <otubo@redhat.com>
Reviewed-by: NBoris Ostrovsky <boris.ostrovsky@oracle.com>
Signed-off-by: NJuergen Gross <jgross@suse.com>
上级 910f8bef
......@@ -2005,7 +2005,10 @@ static void netback_changed(struct xenbus_device *dev,
case XenbusStateInitialised:
case XenbusStateReconfiguring:
case XenbusStateReconfigured:
break;
case XenbusStateUnknown:
wake_up_all(&module_unload_q);
break;
case XenbusStateInitWait:
......@@ -2136,7 +2139,9 @@ static int xennet_remove(struct xenbus_device *dev)
xenbus_switch_state(dev, XenbusStateClosing);
wait_event(module_unload_q,
xenbus_read_driver_state(dev->otherend) ==
XenbusStateClosing);
XenbusStateClosing ||
xenbus_read_driver_state(dev->otherend) ==
XenbusStateUnknown);
xenbus_switch_state(dev, XenbusStateClosed);
wait_event(module_unload_q,
......
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