From: Michael Ellerman The iseries_veth driver is badly behaved in that it will keep TX packets hanging around forever if they're not ACK'ed and the queue never fills up. This causes the unregister_netdevice code to wait forever when we try to take the device down, because there's still skbs around with references to our struct net_device. There's already code to cleanup any un-ACK'ed packets in veth_stop_connection() but it's being called after we unregister the net_device, which is too late. The fix is to rearrange the module exit function so that we cleanup any outstanding skbs and then unregister the driver. Signed-off-by: Michael Ellerman Cc: Jeff Garzik Signed-off-by: Andrew Morton --- drivers/net/iseries_veth.c | 11 +++++++++-- 1 files changed, 9 insertions(+), 2 deletions(-) diff -puN drivers/net/iseries_veth.c~iseries_veth-cleanup-skbs-to-prevent-unregister_netdevice-hanging drivers/net/iseries_veth.c --- 25/drivers/net/iseries_veth.c~iseries_veth-cleanup-skbs-to-prevent-unregister_netdevice-hanging 2005-05-12 01:20:45.000000000 -0700 +++ 25-akpm/drivers/net/iseries_veth.c 2005-05-12 01:20:45.000000000 -0700 @@ -1388,18 +1388,25 @@ void __exit veth_module_cleanup(void) { int i; - vio_unregister_driver(&veth_driver); + /* Stop the queues first to stop any new packets being sent. */ + for (i = 0; i < HVMAXARCHITECTEDVIRTUALLANS; i++) + if (veth_dev[i]) + netif_stop_queue(veth_dev[i]); + /* Stop the connections before we unregister the driver. This + * ensures there's no skbs lying around holding the device open. */ for (i = 0; i < HVMAXARCHITECTEDLPS; ++i) veth_stop_connection(i); HvLpEvent_unregisterHandler(HvLpEvent_Type_VirtualLan); /* Hypervisor callbacks may have scheduled more work while we - * were destroying connections. Now that we've disconnected from + * were stoping connections. Now that we've disconnected from * the hypervisor make sure everything's finished. */ flush_scheduled_work(); + vio_unregister_driver(&veth_driver); + for (i = 0; i < HVMAXARCHITECTEDLPS; ++i) veth_destroy_connection(i); _