xen-netback: protect resource cleaning on XenBus disconnect

vif->lock is used to protect statistics gathering agents from using the
queue structure during cleaning.

Signed-off-by: Igor Druzhinin <igor.druzhinin@citrix.com>
Acked-by: Wei Liu <wei.liu2@citrix.com>
Reviewed-by: Paul Durrant <paul.durrant@citrix.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 2 insertions, 0 deletions

diff --git a/drivers/net/xen-netback/xenbus.c b/drivers/net/xen-netback/xenbus.c
index 34e4af9272ea..85b742e1c42f 100644
--- a/drivers/net/xen-netback/xenbus.c
+++ b/drivers/net/xen-netback/xenbus.c
@@ -503,9 +503,11 @@ static void backend_disconnect(struct backend_info *be)
                 for (queue_index = 0; queue_index < be->vif->num_queues; ++queue_index)
                         xenvif_deinit_queue(&be->vif->queues[queue_index]);
 
+                spin_lock(&be->vif->lock);
                 vfree(be->vif->queues);
                 be->vif->num_queues = 0;
                 be->vif->queues = NULL;
+                spin_unlock(&be->vif->lock);
 
                 xenvif_disconnect_ctrl(be->vif);
         }