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. Therefore, we should always flush all rcu callback functions scheduled during the shutdown procedure.
Signed-off-by: Linus Lüssing <[email protected]> --- main.c | 5 ++--- 1 files changed, 2 insertions(+), 3 deletions(-) diff --git a/main.c b/main.c index 209a46b..e8acb46 100644 --- a/main.c +++ b/main.c @@ -73,6 +73,8 @@ static void __exit batman_exit(void) 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 @@ void mesh_free(struct net_device *soft_iface) hna_local_free(bat_priv); hna_global_free(bat_priv); - synchronize_net(); - - synchronize_rcu(); atomic_set(&bat_priv->mesh_state, MESH_INACTIVE); } -- 1.7.1
