[PATCH] xen: netback: do not unleash netback threads until initialisation is complete

[Ian Campbell <ian.campbell@citrix.com>]

Otherwise netbk_action_thread can reference &netbk->net_schedule_list
(via tx_work_todo) before it is initialised. Until now it was zeroed
which is probably safe but not exactly robust.

Signed-off-by: Ian Campbell <ian.campbell@citrix.com>
Cc: Jeremy Fitzhardinge <jeremy@goop.org>
Cc: Xu, Dongxiao <dongxiao.xu@intel.com>
Cc: Paul Durrant <Paul.Durrant@citrix.com>
---
 drivers/xen/netback/netback.c |    4 +++-
 1 files changed, 3 insertions(+), 1 deletions(-)

diff --git a/drivers/xen/netback/netback.c b/drivers/xen/netback/netback.c
index 4121062..0ed7e61 100644
--- a/drivers/xen/netback/netback.c
+++ b/drivers/xen/netback/netback.c
@@ -1781,7 +1781,6 @@ static int __init netback_init(void)
 
 			if (!IS_ERR(netbk->kthread.task)) {
 				kthread_bind(netbk->kthread.task, group);
-				wake_up_process(netbk->kthread.task);
 			} else {
 				printk(KERN_ALERT
 					"kthread_run() fails at netback\n");
@@ -1807,6 +1806,9 @@ static int __init netback_init(void)
 		spin_lock_init(&netbk->net_schedule_list_lock);
 
 		atomic_set(&netbk->netfront_count, 0);
+
+		if (MODPARM_netback_kthread)
+			wake_up_process(netbk->kthread.task);
 	}
 
 	netbk_copy_skb_mode = NETBK_DONT_COPY_SKB;
-- 
1.5.6.5