caif: Fix access to freed pernet memory

unregister_netdevice_notifier() must be called before
unregister_pernet_subsys() to avoid accessing already freed
pernet memory. This fixes the following oops when doing rmmod:

Call Trace:
 [<ffffffffa0f802bd>] caif_device_notify+0x4d/0x5a0 [caif]
 [<ffffffff81552ba9>] unregister_netdevice_notifier+0xb9/0x100
 [<ffffffffa0f86dcc>] caif_device_exit+0x1c/0x250 [caif]
 [<ffffffff810e7734>] sys_delete_module+0x1a4/0x300
 [<ffffffff810da82d>] ? trace_hardirqs_on_caller+0x15d/0x1e0
 [<ffffffff813517de>] ? trace_hardirqs_on_thunk+0x3a/0x3
 [<ffffffff81696bad>] system_call_fastpath+0x1a/0x1f

RIP
 [<ffffffffa0f7f561>] caif_get+0x51/0xb0 [caif]

Signed-off-by: Sjur Brændeland <[email protected]>
Acked-by: "Eric W. Biederman" <[email protected]>
Signed-off-by: David S. Miller <[email protected]>

diff --git a/net/caif/caif_dev.c b/net/caif/caif_dev.c
index 554b3128960776af52c2cd9869e14fdad224566c..8c83c175b03a9f2379c253bd1c9e160b72457320 100644 (file)
--- a/net/caif/caif_dev.c
+++ b/net/caif/caif_dev.c
@@ -561,9 +561,9 @@ static int __init caif_device_init(void)
 
 static void __exit caif_device_exit(void)
 {
-       unregister_pernet_subsys(&caif_net_ops);
        unregister_netdevice_notifier(&caif_device_notifier);
        dev_remove_pack(&caif_packet_type);
+       unregister_pernet_subsys(&caif_net_ops);
 }
 
 module_init(caif_device_init);