[SCTP]: Re-order SCTP initializations to avoid race with sctp_rcv()

Signed-off-by: Sridhar Samudrala <sri@us.ibm.com>
Signed-off-by: Vlad Yasevich <vladislav.yasevich@hp.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

2 files changed, 75 insertions, 53 deletions

diff --git a/net/sctp/ipv6.c b/net/sctp/ipv6.c
index ca527a27dd05..84cd53635fe8 100644
--- a/net/sctp/ipv6.c
+++ b/net/sctp/ipv6.c
@@ -992,45 +992,52 @@ static struct sctp_pf sctp_pf_inet6_specific = {
         .af            = &sctp_ipv6_specific,
 };
 
-/* Initialize IPv6 support and register with inet6 stack.  */
+/* Initialize IPv6 support and register with socket layer.  */
 int sctp_v6_init(void)
 {
-        int rc = proto_register(&sctpv6_prot, 1);
+        int rc;
 
+        /* Register the SCTP specific PF_INET6 functions. */
+        sctp_register_pf(&sctp_pf_inet6_specific, PF_INET6);
+
+        /* Register the SCTP specific AF_INET6 functions. */
+        sctp_register_af(&sctp_ipv6_specific);
+
+        rc = proto_register(&sctpv6_prot, 1);
         if (rc)
-                goto out;
-        /* Register inet6 protocol. */
-        rc = -EAGAIN;
-        if (inet6_add_protocol(&sctpv6_protocol, IPPROTO_SCTP) < 0)
-                goto out_unregister_sctp_proto;
+                return rc;
 
         /* Add SCTPv6(UDP and TCP style) to inetsw6 linked list. */
         inet6_register_protosw(&sctpv6_seqpacket_protosw);
         inet6_register_protosw(&sctpv6_stream_protosw);
 
-        /* Register the SCTP specific PF_INET6 functions. */
-        sctp_register_pf(&sctp_pf_inet6_specific, PF_INET6);
-
-        /* Register the SCTP specific AF_INET6 functions. */
-        sctp_register_af(&sctp_ipv6_specific);
+        return 0;
+}
 
+/* Register with inet6 layer. */
+int sctp_v6_add_protocol(void)
+{
         /* Register notifier for inet6 address additions/deletions. */
         register_inet6addr_notifier(&sctp_inet6addr_notifier);
-        rc = 0;
-out:
-        return rc;
-out_unregister_sctp_proto:
-        proto_unregister(&sctpv6_prot);
-        goto out;
+
+        if (inet6_add_protocol(&sctpv6_protocol, IPPROTO_SCTP) < 0)
+                return -EAGAIN;
+
+        return 0;
 }
 
 /* IPv6 specific exit support. */
 void sctp_v6_exit(void)
 {
-        list_del(&sctp_ipv6_specific.list);
-        inet6_del_protocol(&sctpv6_protocol, IPPROTO_SCTP);
         inet6_unregister_protosw(&sctpv6_seqpacket_protosw);
         inet6_unregister_protosw(&sctpv6_stream_protosw);
-        unregister_inet6addr_notifier(&sctp_inet6addr_notifier);
         proto_unregister(&sctpv6_prot);
+        list_del(&sctp_ipv6_specific.list);
+}
+
+/* Unregister with inet6 layer. */
+void sctp_v6_del_protocol(void)
+{
+        inet6_del_protocol(&sctpv6_protocol, IPPROTO_SCTP);
+        unregister_inet6addr_notifier(&sctp_inet6addr_notifier);
 }
diff --git a/net/sctp/protocol.c b/net/sctp/protocol.c
index d4afafc39138..34bab36637ac 100644
--- a/net/sctp/protocol.c
+++ b/net/sctp/protocol.c
@@ -975,28 +975,14 @@ SCTP_STATIC __init int sctp_init(void)
         if (!sctp_sanity_check())
                 goto out;
 
-        status = proto_register(&sctp_prot, 1);
-        if (status)
-                goto out;
-
-        /* Add SCTP to inet_protos hash table.  */
-        status = -EAGAIN;
-        if (inet_add_protocol(&sctp_protocol, IPPROTO_SCTP) < 0)
-                goto err_add_protocol;
-
-        /* Add SCTP(TCP and UDP style) to inetsw linked list.  */
-        inet_register_protosw(&sctp_seqpacket_protosw);
-        inet_register_protosw(&sctp_stream_protosw);
-
-        /* Allocate a cache pools. */
+        /* Allocate bind_bucket and chunk caches. */
         status = -ENOBUFS;
         sctp_bucket_cachep = kmem_cache_create("sctp_bind_bucket",
                                                sizeof(struct sctp_bind_bucket),
                                                0, SLAB_HWCACHE_ALIGN,
                                                NULL, NULL);
-
         if (!sctp_bucket_cachep)
-                goto err_bucket_cachep;
+                goto out;
 
         sctp_chunk_cachep = kmem_cache_create("sctp_chunk",
                                                sizeof(struct sctp_chunk),
@@ -1153,6 +1139,14 @@ SCTP_STATIC __init int sctp_init(void)
         INIT_LIST_HEAD(&sctp_address_families);
         sctp_register_af(&sctp_ipv4_specific);
 
+        status = proto_register(&sctp_prot, 1);
+        if (status)
+                goto err_proto_register;
+
+        /* Register SCTP(UDP and TCP style) with socket layer.  */
+        inet_register_protosw(&sctp_seqpacket_protosw);
+        inet_register_protosw(&sctp_stream_protosw);
+
         status = sctp_v6_init();
         if (status)
                 goto err_v6_init;
@@ -1166,19 +1160,39 @@ SCTP_STATIC __init int sctp_init(void)
 
         /* Initialize the local address list. */
         INIT_LIST_HEAD(&sctp_local_addr_list);
-
         sctp_get_local_addr_list();
 
         /* Register notifier for inet address additions/deletions. */
         register_inetaddr_notifier(&sctp_inetaddr_notifier);
 
+        /* Register SCTP with inet layer.  */
+        if (inet_add_protocol(&sctp_protocol, IPPROTO_SCTP) < 0) {
+                status = -EAGAIN;
+                goto err_add_protocol;
+        }
+
+        /* Register SCTP with inet6 layer.  */
+        status = sctp_v6_add_protocol();
+        if (status)
+                goto err_v6_add_protocol;
+
         __unsafe(THIS_MODULE);
         status = 0;
 out:
         return status;
+err_v6_add_protocol:
+        inet_del_protocol(&sctp_protocol, IPPROTO_SCTP);
+        unregister_inetaddr_notifier(&sctp_inetaddr_notifier);
+err_add_protocol:
+        sctp_free_local_addr_list();
+        sock_release(sctp_ctl_socket);
 err_ctl_sock_init:
         sctp_v6_exit();
 err_v6_init:
+        inet_unregister_protosw(&sctp_stream_protosw);
+        inet_unregister_protosw(&sctp_seqpacket_protosw);
+        proto_unregister(&sctp_prot);
+err_proto_register:
         sctp_sysctl_unregister();
         list_del(&sctp_ipv4_specific.list);
         free_pages((unsigned long)sctp_port_hashtable,
@@ -1192,19 +1206,13 @@ err_ehash_alloc:
                              sizeof(struct sctp_hashbucket)));
 err_ahash_alloc:
         sctp_dbg_objcnt_exit();
-err_init_proc:
         sctp_proc_exit();
+err_init_proc:
         cleanup_sctp_mibs();
 err_init_mibs:
         kmem_cache_destroy(sctp_chunk_cachep);
 err_chunk_cachep:
         kmem_cache_destroy(sctp_bucket_cachep);
-err_bucket_cachep:
-        inet_del_protocol(&sctp_protocol, IPPROTO_SCTP);
-        inet_unregister_protosw(&sctp_seqpacket_protosw);
-        inet_unregister_protosw(&sctp_stream_protosw);
-err_add_protocol:
-        proto_unregister(&sctp_prot);
         goto out;
 }
 
@@ -1215,8 +1223,9 @@ SCTP_STATIC __exit void sctp_exit(void)
          * up all the remaining associations and all that memory.
          */
 
-        /* Unregister notifier for inet address additions/deletions. */
-        unregister_inetaddr_notifier(&sctp_inetaddr_notifier);
+        /* Unregister with inet6/inet layers. */
+        sctp_v6_del_protocol();
+        inet_del_protocol(&sctp_protocol, IPPROTO_SCTP);
 
         /* Free the local address list.  */
         sctp_free_local_addr_list();
@@ -1224,7 +1233,16 @@ SCTP_STATIC __exit void sctp_exit(void)
         /* Free the control endpoint.  */
         sock_release(sctp_ctl_socket);
 
+        /* Cleanup v6 initializations. */
         sctp_v6_exit();
+
+        /* Unregister with socket layer. */
+        inet_unregister_protosw(&sctp_stream_protosw);
+        inet_unregister_protosw(&sctp_seqpacket_protosw);
+
+        /* Unregister notifier for inet address additions/deletions. */
+        unregister_inetaddr_notifier(&sctp_inetaddr_notifier);
+
         sctp_sysctl_unregister();
         list_del(&sctp_ipv4_specific.list);
 
@@ -1236,16 +1254,13 @@ SCTP_STATIC __exit void sctp_exit(void)
                    get_order(sctp_port_hashsize *
                              sizeof(struct sctp_bind_hashbucket)));
 
-        kmem_cache_destroy(sctp_chunk_cachep);
-        kmem_cache_destroy(sctp_bucket_cachep);
-
         sctp_dbg_objcnt_exit();
         sctp_proc_exit();
         cleanup_sctp_mibs();
 
-        inet_del_protocol(&sctp_protocol, IPPROTO_SCTP);
-        inet_unregister_protosw(&sctp_seqpacket_protosw);
-        inet_unregister_protosw(&sctp_stream_protosw);
+        kmem_cache_destroy(sctp_chunk_cachep);
+        kmem_cache_destroy(sctp_bucket_cachep);
+
         proto_unregister(&sctp_prot);
 }