linux_dsm_epyc7002/net/tipc/core.c
Hoang Huu Le d966ddcc38 tipc: fix a deadlock when flushing scheduled work
In the commit fdeba99b1e
("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>
2020-09-07 12:08:53 -07:00

231 lines
5.9 KiB
C

/*
* net/tipc/core.c: TIPC module code
*
* Copyright (c) 2003-2006, 2013, Ericsson AB
* Copyright (c) 2005-2006, 2010-2013, Wind River Systems
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions are met:
*
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
* 3. Neither the names of the copyright holders nor the names of its
* contributors may be used to endorse or promote products derived from
* this software without specific prior written permission.
*
* Alternatively, this software may be distributed under the terms of the
* GNU General Public License ("GPL") version 2 as published by the Free
* Software Foundation.
*
* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
* AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
* ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE
* LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
* CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
* SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
* INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
* CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
* ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
* POSSIBILITY OF SUCH DAMAGE.
*/
#include "core.h"
#include "name_table.h"
#include "subscr.h"
#include "bearer.h"
#include "net.h"
#include "socket.h"
#include "bcast.h"
#include "node.h"
#include "crypto.h"
#include <linux/module.h>
/* configurable TIPC parameters */
unsigned int tipc_net_id __read_mostly;
int sysctl_tipc_rmem[3] __read_mostly; /* min/default/max */
static int __net_init tipc_init_net(struct net *net)
{
struct tipc_net *tn = net_generic(net, tipc_net_id);
int err;
tn->net_id = 4711;
tn->node_addr = 0;
tn->trial_addr = 0;
tn->addr_trial_end = 0;
tn->capabilities = TIPC_NODE_CAPABILITIES;
INIT_WORK(&tn->final_work.work, tipc_net_finalize_work);
memset(tn->node_id, 0, sizeof(tn->node_id));
memset(tn->node_id_string, 0, sizeof(tn->node_id_string));
tn->mon_threshold = TIPC_DEF_MON_THRESHOLD;
get_random_bytes(&tn->random, sizeof(int));
INIT_LIST_HEAD(&tn->node_list);
spin_lock_init(&tn->node_list_lock);
#ifdef CONFIG_TIPC_CRYPTO
err = tipc_crypto_start(&tn->crypto_tx, net, NULL);
if (err)
goto out_crypto;
#endif
err = tipc_sk_rht_init(net);
if (err)
goto out_sk_rht;
err = tipc_nametbl_init(net);
if (err)
goto out_nametbl;
INIT_LIST_HEAD(&tn->dist_queue);
err = tipc_bcast_init(net);
if (err)
goto out_bclink;
err = tipc_attach_loopback(net);
if (err)
goto out_bclink;
return 0;
out_bclink:
tipc_nametbl_stop(net);
out_nametbl:
tipc_sk_rht_destroy(net);
out_sk_rht:
#ifdef CONFIG_TIPC_CRYPTO
tipc_crypto_stop(&tn->crypto_tx);
out_crypto:
#endif
return err;
}
static void __net_exit tipc_exit_net(struct net *net)
{
struct tipc_net *tn = tipc_net(net);
tipc_detach_loopback(net);
/* Make sure the tipc_net_finalize_work() finished */
cancel_work_sync(&tn->final_work.work);
tipc_net_stop(net);
tipc_bcast_stop(net);
tipc_nametbl_stop(net);
tipc_sk_rht_destroy(net);
#ifdef CONFIG_TIPC_CRYPTO
tipc_crypto_stop(&tipc_net(net)->crypto_tx);
#endif
}
static void __net_exit tipc_pernet_pre_exit(struct net *net)
{
tipc_node_pre_cleanup_net(net);
}
static struct pernet_operations tipc_pernet_pre_exit_ops = {
.pre_exit = tipc_pernet_pre_exit,
};
static struct pernet_operations tipc_net_ops = {
.init = tipc_init_net,
.exit = tipc_exit_net,
.id = &tipc_net_id,
.size = sizeof(struct tipc_net),
};
static struct pernet_operations tipc_topsrv_net_ops = {
.init = tipc_topsrv_init_net,
.exit = tipc_topsrv_exit_net,
};
static int __init tipc_init(void)
{
int err;
pr_info("Activated (version " TIPC_MOD_VER ")\n");
sysctl_tipc_rmem[0] = RCVBUF_MIN;
sysctl_tipc_rmem[1] = RCVBUF_DEF;
sysctl_tipc_rmem[2] = RCVBUF_MAX;
err = tipc_register_sysctl();
if (err)
goto out_sysctl;
err = register_pernet_device(&tipc_net_ops);
if (err)
goto out_pernet;
err = tipc_socket_init();
if (err)
goto out_socket;
err = register_pernet_device(&tipc_topsrv_net_ops);
if (err)
goto out_pernet_topsrv;
err = register_pernet_subsys(&tipc_pernet_pre_exit_ops);
if (err)
goto out_register_pernet_subsys;
err = tipc_bearer_setup();
if (err)
goto out_bearer;
err = tipc_netlink_start();
if (err)
goto out_netlink;
err = tipc_netlink_compat_start();
if (err)
goto out_netlink_compat;
pr_info("Started in single node mode\n");
return 0;
out_netlink_compat:
tipc_netlink_stop();
out_netlink:
tipc_bearer_cleanup();
out_bearer:
unregister_pernet_subsys(&tipc_pernet_pre_exit_ops);
out_register_pernet_subsys:
unregister_pernet_device(&tipc_topsrv_net_ops);
out_pernet_topsrv:
tipc_socket_stop();
out_socket:
unregister_pernet_device(&tipc_net_ops);
out_pernet:
tipc_unregister_sysctl();
out_sysctl:
pr_err("Unable to start in single node mode\n");
return err;
}
static void __exit tipc_exit(void)
{
tipc_netlink_compat_stop();
tipc_netlink_stop();
tipc_bearer_cleanup();
unregister_pernet_subsys(&tipc_pernet_pre_exit_ops);
unregister_pernet_device(&tipc_topsrv_net_ops);
tipc_socket_stop();
unregister_pernet_device(&tipc_net_ops);
tipc_unregister_sysctl();
pr_info("Deactivated\n");
}
module_init(tipc_init);
module_exit(tipc_exit);
MODULE_DESCRIPTION("TIPC: Transparent Inter Process Communication");
MODULE_LICENSE("Dual BSD/GPL");
MODULE_VERSION(TIPC_MOD_VER);