[PATCH] can: gw: Fix error path of cgw_module_init

[YueHaibing]

This patch fix error path for cgw_module_init
to avoid possible crash if some error occurs.

Fixes: c1aabdf379bc ("can-gw: add netlink based CAN routing")
Signed-off-by: YueHaibing <yuehaib...@huawei.com>
---
 net/can/gw.c | 46 +++++++++++++++++++++++++++++++---------------
 1 file changed, 31 insertions(+), 15 deletions(-)

diff --git a/net/can/gw.c b/net/can/gw.c
index 53859346..8b53ec7 100644
--- a/net/can/gw.c
+++ b/net/can/gw.c
@@ -1046,32 +1046,48 @@ static __init int cgw_module_init(void)
        pr_info("can: netlink gateway (rev " CAN_GW_VERSION ") max_hops=%d\n",
                max_hops);
 
-       register_pernet_subsys(&cangw_pernet_ops);
+       ret = register_pernet_subsys(&cangw_pernet_ops);
+       if (ret)
+               return ret;
+
+       ret = -ENOMEM;
        cgw_cache = kmem_cache_create("can_gw", sizeof(struct cgw_job),
                                      0, 0, NULL);
-
        if (!cgw_cache)
-               return -ENOMEM;
+               goto out_cache_create;
 
        /* set notifier */
        notifier.notifier_call = cgw_notifier;
-       register_netdevice_notifier(&notifier);
+       ret = register_netdevice_notifier(&notifier);
+       if (ret)
+               goto out_register_notifier;
 
        ret = rtnl_register_module(THIS_MODULE, PF_CAN, RTM_GETROUTE,
                                   NULL, cgw_dump_jobs, 0);
-       if (ret) {
-               unregister_netdevice_notifier(&notifier);
-               kmem_cache_destroy(cgw_cache);
-               return -ENOBUFS;
-       }
-
-       /* Only the first call to rtnl_register_module can fail */
-       rtnl_register_module(THIS_MODULE, PF_CAN, RTM_NEWROUTE,
-                            cgw_create_job, NULL, 0);
-       rtnl_register_module(THIS_MODULE, PF_CAN, RTM_DELROUTE,
-                            cgw_remove_job, NULL, 0);
+       if (ret)
+               goto out_rtnl_register1;
+
+       ret = rtnl_register_module(THIS_MODULE, PF_CAN, RTM_NEWROUTE,
+                                  cgw_create_job, NULL, 0);
+       if (ret)
+               goto out_rtnl_register2;
+       ret = rtnl_register_module(THIS_MODULE, PF_CAN, RTM_DELROUTE,
+                                  cgw_remove_job, NULL, 0);
+       if (ret)
+               goto out_rtnl_register2;
 
        return 0;
+
+out_rtnl_register2:
+       rtnl_unregister_all(PF_CAN);
+out_rtnl_register1:
+       unregister_netdevice_notifier(&notifier);
+out_register_notifier:
+       kmem_cache_destroy(cgw_cache);
+out_cache_create:
+       unregister_pernet_subsys(&cangw_pernet_ops);
+
+       return ret;
 }
 
 static __exit void cgw_module_exit(void)
-- 
1.8.3.1