@@ -638,19 +638,19 @@ static int rds_tcp_init(void)
goto out;
}
- ret = register_netdevice_notifier(&rds_tcp_dev_notifier);
- if (ret) {
- pr_warn("could not register rds_tcp_dev_notifier\n");
+ ret = rds_tcp_recv_init();
+ if (ret)
goto out_slab;
- }
ret = register_pernet_subsys(&rds_tcp_net_ops);
if (ret)
- goto out_notifier;
+ goto out_recv;
- ret = rds_tcp_recv_init();
- if (ret)
+ ret = register_netdevice_notifier(&rds_tcp_dev_notifier);
+ if (ret) {
+ pr_warn("could not register rds_tcp_dev_notifier\n");
goto out_pernet;
+ }
rds_trans_register(&rds_tcp_transport);
@@ -660,9 +660,8 @@ static int rds_tcp_init(void)
out_pernet:
unregister_pernet_subsys(&rds_tcp_net_ops);
-out_notifier:
- if (unregister_netdevice_notifier(&rds_tcp_dev_notifier))
- pr_warn("could not unregister rds_tcp_dev_notifier\n");
+out_recv:
+ rds_tcp_recv_exit();
out_slab:
kmem_cache_destroy(rds_tcp_conn_slab);
out:
Order of initialization in rds_tcp_init needs to be done so that resources are set up and destroyed in the correct synchronization sequence with both the data path, as well as netns create/destroy path. Specifically, - we must call register_pernet_subsys and get the rds_tcp_netid before calling register_netdevice_notifier, otherwise we risk the sequence 1. register_netdevice_notifier sets up netdev notifier callback 2. rds_tcp_dev_event -> rds_tcp_kill_sock uses netid 0, and finds the wrong rtn, resulting in a panic with string that is of the form: BUG: unable to handle kernel NULL pointer dereference at 000000000000000d IP: rds_tcp_kill_sock+0x3a/0x1d0 [rds_tcp] : - the rds_tcp_incoming_slab kmem_cache must be initialized before the datapath starts up. The latter can happen any time after the pernet_subsys registration of rds_tcp_net_ops, whose -> init function sets up the listen socket. If the rds_tcp_incoming_slab has not been set up at that time, a panic of the form below may be encountered BUG: unable to handle kernel NULL pointer dereference at 0000000000000014 IP: kmem_cache_alloc+0x90/0x1c0 : rds_tcp_data_recv+0x1e7/0x370 [rds_tcp] tcp_read_sock+0x96/0x1c0 rds_tcp_recv_path+0x65/0x80 [rds_tcp] : Signed-off-by: Sowmini Varadhan <sowmini.varadhan@oracle.com> --- net/rds/tcp.c | 19 +++++++++---------- 1 files changed, 9 insertions(+), 10 deletions(-)