xen-netback: only deinitialized hash if it was initialized

A domain with a frontend that does not implement a control ring has been
seen to cause a crash during domain save. This was apparently because
the call to xenvif_deinit_hash() in xenvif_disconnect_ctrl() is made
regardless of whether a control ring was connected, and hence
xenvif_hash_init() was called.

This patch brings the call to xenvif_deinit_hash() in
xenvif_disconnect_ctrl() inside the if clause that checks whether the
control ring event channel was connected. This is sufficient to ensure
it is only called if xenvif_init_hash() was called previously.

Signed-off-by: Paul Durrant <paul.durrant@citrix.com>
Reported-by: Boris Ostrovsky <boris.ostrovsky@oracle.com>
Tested-by: Boris Ostrovsky <boris.ostrovsky@oracle.com>
Cc: Wei Liu <wei.liu2@citrix.com>
Acked-by: Wei Liu <wei.liu2@citrix.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

diff --git a/drivers/net/xen-netback/interface.c b/drivers/net/xen-netback/interface.c
index 1c7f49b..83deeeb 100644 (file)
--- a/drivers/net/xen-netback/interface.c
+++ b/drivers/net/xen-netback/interface.c
@@ -780,9 +780,8 @@ void xenvif_disconnect_ctrl(struct xenvif *vif)
                vif->ctrl_task = NULL;
        }
 
-       xenvif_deinit_hash(vif);
-
        if (vif->ctrl_irq) {
+               xenvif_deinit_hash(vif);
                unbind_from_irqhandler(vif->ctrl_irq, vif);
                vif->ctrl_irq = 0;
        }