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authorJason Andryuk <jandryuk@gmail.com>2018-02-28 07:23:23 -0500
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>2018-04-24 09:32:06 +0200
commit4c65e94eb476b8e7d806d7e36ca1f5f789e9804a (patch)
treec5c7756efb02d7e8fb227e6639899185812dcd13 /drivers/net/xen-netfront.c
parent318a306c53d17fa333d888d29c45268c6a8b1783 (diff)
xen-netfront: Fix hang on device removal
commit c2d2e6738a209f0f9dffa2dc8e7292fc45360d61 upstream. 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 <jandryuk@gmail.com> Cc: Eduardo Otubo <otubo@redhat.com> Reviewed-by: Boris Ostrovsky <boris.ostrovsky@oracle.com> Signed-off-by: Juergen Gross <jgross@suse.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Diffstat (limited to 'drivers/net/xen-netfront.c')
-rw-r--r--drivers/net/xen-netfront.c7
1 files changed, 6 insertions, 1 deletions
diff --git a/drivers/net/xen-netfront.c b/drivers/net/xen-netfront.c
index 0b8d2655985f..fee4c01fbdfd 100644
--- a/drivers/net/xen-netfront.c
+++ b/drivers/net/xen-netfront.c
@@ -2024,7 +2024,10 @@ 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:
@@ -2155,7 +2158,9 @@ 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,