Author: marek Date: 2010-09-06 16:08:05 +0200 (Mon, 06 Sep 2010) New Revision: 1788

Modified: trunk/batman-adv/main.c Log: batman-adv: Always synchronize rcu's on module shutdown

During the module shutdown procedure in batman_exit(), a rcu callback is being scheduled (batman_exit -> hardif_remove_interfaces -> hardif_remove_interfae -> call_rcu). However, when the kernel unloads the module, the rcu callback might not have been executed yet, resulting in a "unable to handle kernel paging request" in __rcu_process_callback afterwards, causing the kernel to freeze.

The synchronize_net and synchronize_rcu in mesh_free are currently called before the call_rcu in hardif_remove_interface and have no real effect on it.

Therefore, we should always flush all rcu callback functions scheduled during the shutdown procedure using synchronize_net. The call to synchronize_rcu can be omitted because synchronize_net already calls it.

Signed-off-by: Linus L?\195?\188ssing linus.luessing@web.de Acked-by: Sven Eckelmann sven.eckelmann@gmx.de

Modified: trunk/batman-adv/main.c =================================================================== --- trunk/batman-adv/main.c 2010-09-04 23:47:38 UTC (rev 1787) +++ trunk/batman-adv/main.c 2010-09-06 14:08:05 UTC (rev 1788) @@ -73,6 +73,8 @@ flush_workqueue(bat_event_workqueue); destroy_workqueue(bat_event_workqueue); bat_event_workqueue = NULL; + + synchronize_net(); }

int mesh_init(struct net_device *soft_iface) @@ -135,9 +137,6 @@ hna_local_free(bat_priv); hna_global_free(bat_priv);

- synchronize_net(); - - synchronize_rcu(); atomic_set(&bat_priv->mesh_state, MESH_INACTIVE); }