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d966ddcc38
In the commitfdeba99b1e
("tipc: fix use-after-free in tipc_bcast_get_mode"), we're trying to make sure the tipc_net_finalize_work work item finished if it enqueued. But calling flush_scheduled_work() is not just affecting above work item but either any scheduled work. This has turned out to be overkill and caused to deadlock as syzbot reported: ====================================================== WARNING: possible circular locking dependency detected 5.9.0-rc2-next-20200828-syzkaller #0 Not tainted ------------------------------------------------------ kworker/u4:6/349 is trying to acquire lock: ffff8880aa063d38 ((wq_completion)events){+.+.}-{0:0}, at: flush_workqueue+0xe1/0x13e0 kernel/workqueue.c:2777 but task is already holding lock: ffffffff8a879430 (pernet_ops_rwsem){++++}-{3:3}, at: cleanup_net+0x9b/0xb10 net/core/net_namespace.c:565 [...] Possible unsafe locking scenario: CPU0 CPU1 ---- ---- lock(pernet_ops_rwsem); lock(&sb->s_type->i_mutex_key#13); lock(pernet_ops_rwsem); lock((wq_completion)events); *** DEADLOCK *** [...] v1: To fix the original issue, we replace above calling by introducing a bit flag. When a namespace cleaned-up, bit flag is set to zero and: - tipc_net_finalize functionial just does return immediately. - tipc_net_finalize_work does not enqueue into the scheduled work queue. v2: Use cancel_work_sync() helper to make sure ONLY the tipc_net_finalize_work() stopped before releasing bcbase object. Reported-by: syzbot+d5aa7e0385f6a5d0f4fd@syzkaller.appspotmail.com Fixes:fdeba99b1e
("tipc: fix use-after-free in tipc_bcast_get_mode") Acked-by: Jon Maloy <jmaloy@redhat.com> Signed-off-by: Hoang Huu Le <hoang.h.le@dektech.com.au> Signed-off-by: Jakub Kicinski <kuba@kernel.org>
231 lines
5.9 KiB
C
231 lines
5.9 KiB
C
/*
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* net/tipc/core.c: TIPC module code
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*
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* Copyright (c) 2003-2006, 2013, Ericsson AB
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* Copyright (c) 2005-2006, 2010-2013, Wind River Systems
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* All rights reserved.
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions are met:
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*
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* 1. Redistributions of source code must retain the above copyright
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* notice, this list of conditions and the following disclaimer.
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* 2. Redistributions in binary form must reproduce the above copyright
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* notice, this list of conditions and the following disclaimer in the
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* documentation and/or other materials provided with the distribution.
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* 3. Neither the names of the copyright holders nor the names of its
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* contributors may be used to endorse or promote products derived from
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* this software without specific prior written permission.
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*
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* Alternatively, this software may be distributed under the terms of the
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* GNU General Public License ("GPL") version 2 as published by the Free
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* Software Foundation.
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*
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* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
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* AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
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* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
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* ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE
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* LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
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* CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
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* SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
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* INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
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* CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
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* ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
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* POSSIBILITY OF SUCH DAMAGE.
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*/
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#include "core.h"
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#include "name_table.h"
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#include "subscr.h"
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#include "bearer.h"
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#include "net.h"
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#include "socket.h"
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#include "bcast.h"
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#include "node.h"
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#include "crypto.h"
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#include <linux/module.h>
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/* configurable TIPC parameters */
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unsigned int tipc_net_id __read_mostly;
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int sysctl_tipc_rmem[3] __read_mostly; /* min/default/max */
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static int __net_init tipc_init_net(struct net *net)
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{
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struct tipc_net *tn = net_generic(net, tipc_net_id);
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int err;
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tn->net_id = 4711;
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tn->node_addr = 0;
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tn->trial_addr = 0;
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tn->addr_trial_end = 0;
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tn->capabilities = TIPC_NODE_CAPABILITIES;
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INIT_WORK(&tn->final_work.work, tipc_net_finalize_work);
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memset(tn->node_id, 0, sizeof(tn->node_id));
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memset(tn->node_id_string, 0, sizeof(tn->node_id_string));
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tn->mon_threshold = TIPC_DEF_MON_THRESHOLD;
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get_random_bytes(&tn->random, sizeof(int));
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INIT_LIST_HEAD(&tn->node_list);
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spin_lock_init(&tn->node_list_lock);
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#ifdef CONFIG_TIPC_CRYPTO
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err = tipc_crypto_start(&tn->crypto_tx, net, NULL);
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if (err)
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goto out_crypto;
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#endif
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err = tipc_sk_rht_init(net);
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if (err)
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goto out_sk_rht;
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err = tipc_nametbl_init(net);
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if (err)
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goto out_nametbl;
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INIT_LIST_HEAD(&tn->dist_queue);
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err = tipc_bcast_init(net);
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if (err)
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goto out_bclink;
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err = tipc_attach_loopback(net);
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if (err)
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goto out_bclink;
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return 0;
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out_bclink:
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tipc_nametbl_stop(net);
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out_nametbl:
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tipc_sk_rht_destroy(net);
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out_sk_rht:
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#ifdef CONFIG_TIPC_CRYPTO
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tipc_crypto_stop(&tn->crypto_tx);
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out_crypto:
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#endif
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return err;
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}
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static void __net_exit tipc_exit_net(struct net *net)
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{
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struct tipc_net *tn = tipc_net(net);
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tipc_detach_loopback(net);
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/* Make sure the tipc_net_finalize_work() finished */
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cancel_work_sync(&tn->final_work.work);
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tipc_net_stop(net);
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tipc_bcast_stop(net);
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tipc_nametbl_stop(net);
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tipc_sk_rht_destroy(net);
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#ifdef CONFIG_TIPC_CRYPTO
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tipc_crypto_stop(&tipc_net(net)->crypto_tx);
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#endif
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}
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static void __net_exit tipc_pernet_pre_exit(struct net *net)
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{
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tipc_node_pre_cleanup_net(net);
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}
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static struct pernet_operations tipc_pernet_pre_exit_ops = {
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.pre_exit = tipc_pernet_pre_exit,
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};
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static struct pernet_operations tipc_net_ops = {
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.init = tipc_init_net,
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.exit = tipc_exit_net,
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.id = &tipc_net_id,
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.size = sizeof(struct tipc_net),
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};
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static struct pernet_operations tipc_topsrv_net_ops = {
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.init = tipc_topsrv_init_net,
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.exit = tipc_topsrv_exit_net,
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};
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static int __init tipc_init(void)
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{
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int err;
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pr_info("Activated (version " TIPC_MOD_VER ")\n");
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sysctl_tipc_rmem[0] = RCVBUF_MIN;
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sysctl_tipc_rmem[1] = RCVBUF_DEF;
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sysctl_tipc_rmem[2] = RCVBUF_MAX;
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err = tipc_register_sysctl();
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if (err)
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goto out_sysctl;
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err = register_pernet_device(&tipc_net_ops);
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if (err)
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goto out_pernet;
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err = tipc_socket_init();
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if (err)
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goto out_socket;
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err = register_pernet_device(&tipc_topsrv_net_ops);
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if (err)
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goto out_pernet_topsrv;
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err = register_pernet_subsys(&tipc_pernet_pre_exit_ops);
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if (err)
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goto out_register_pernet_subsys;
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err = tipc_bearer_setup();
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if (err)
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goto out_bearer;
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err = tipc_netlink_start();
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if (err)
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goto out_netlink;
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err = tipc_netlink_compat_start();
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if (err)
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goto out_netlink_compat;
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pr_info("Started in single node mode\n");
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return 0;
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out_netlink_compat:
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tipc_netlink_stop();
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out_netlink:
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tipc_bearer_cleanup();
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out_bearer:
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unregister_pernet_subsys(&tipc_pernet_pre_exit_ops);
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out_register_pernet_subsys:
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unregister_pernet_device(&tipc_topsrv_net_ops);
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out_pernet_topsrv:
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tipc_socket_stop();
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out_socket:
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unregister_pernet_device(&tipc_net_ops);
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out_pernet:
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tipc_unregister_sysctl();
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out_sysctl:
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pr_err("Unable to start in single node mode\n");
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return err;
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}
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static void __exit tipc_exit(void)
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{
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tipc_netlink_compat_stop();
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tipc_netlink_stop();
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tipc_bearer_cleanup();
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unregister_pernet_subsys(&tipc_pernet_pre_exit_ops);
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unregister_pernet_device(&tipc_topsrv_net_ops);
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tipc_socket_stop();
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unregister_pernet_device(&tipc_net_ops);
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tipc_unregister_sysctl();
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pr_info("Deactivated\n");
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}
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module_init(tipc_init);
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module_exit(tipc_exit);
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MODULE_DESCRIPTION("TIPC: Transparent Inter Process Communication");
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MODULE_LICENSE("Dual BSD/GPL");
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MODULE_VERSION(TIPC_MOD_VER);
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