linux_dsm_epyc7002/net/tipc/core.h
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

224 lines
5.7 KiB
C

/*
* net/tipc/core.h: Include file for TIPC global declarations
*
* Copyright (c) 2005-2006, 2013-2018 Ericsson AB
* Copyright (c) 2005-2007, 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.
*/
#ifndef _TIPC_CORE_H
#define _TIPC_CORE_H
#include <linux/tipc.h>
#include <linux/tipc_config.h>
#include <linux/tipc_netlink.h>
#include <linux/types.h>
#include <linux/kernel.h>
#include <linux/errno.h>
#include <linux/mm.h>
#include <linux/timer.h>
#include <linux/string.h>
#include <linux/uaccess.h>
#include <linux/interrupt.h>
#include <linux/atomic.h>
#include <linux/netdevice.h>
#include <linux/in.h>
#include <linux/list.h>
#include <linux/slab.h>
#include <linux/vmalloc.h>
#include <linux/rtnetlink.h>
#include <linux/etherdevice.h>
#include <net/netns/generic.h>
#include <linux/rhashtable.h>
#include <net/genetlink.h>
#include <net/netns/hash.h>
#ifdef pr_fmt
#undef pr_fmt
#endif
#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
struct tipc_node;
struct tipc_bearer;
struct tipc_bc_base;
struct tipc_link;
struct tipc_name_table;
struct tipc_topsrv;
struct tipc_monitor;
#ifdef CONFIG_TIPC_CRYPTO
struct tipc_crypto;
#endif
#define TIPC_MOD_VER "2.0.0"
#define NODE_HTABLE_SIZE 512
#define MAX_BEARERS 3
#define TIPC_DEF_MON_THRESHOLD 32
#define NODE_ID_LEN 16
#define NODE_ID_STR_LEN (NODE_ID_LEN * 2 + 1)
extern unsigned int tipc_net_id __read_mostly;
extern int sysctl_tipc_rmem[3] __read_mostly;
extern int sysctl_tipc_named_timeout __read_mostly;
struct tipc_net_work {
struct work_struct work;
struct net *net;
u32 addr;
};
struct tipc_net {
u8 node_id[NODE_ID_LEN];
u32 node_addr;
u32 trial_addr;
unsigned long addr_trial_end;
char node_id_string[NODE_ID_STR_LEN];
int net_id;
int random;
bool legacy_addr_format;
/* Node table and node list */
spinlock_t node_list_lock;
struct hlist_head node_htable[NODE_HTABLE_SIZE];
struct list_head node_list;
u32 num_nodes;
u32 num_links;
/* Neighbor monitoring list */
struct tipc_monitor *monitors[MAX_BEARERS];
int mon_threshold;
/* Bearer list */
struct tipc_bearer __rcu *bearer_list[MAX_BEARERS + 1];
/* Broadcast link */
spinlock_t bclock;
struct tipc_bc_base *bcbase;
struct tipc_link *bcl;
/* Socket hash table */
struct rhashtable sk_rht;
/* Name table */
spinlock_t nametbl_lock;
struct name_table *nametbl;
/* Name dist queue */
struct list_head dist_queue;
/* Topology subscription server */
struct tipc_topsrv *topsrv;
atomic_t subscription_count;
/* Cluster capabilities */
u16 capabilities;
/* Tracing of node internal messages */
struct packet_type loopback_pt;
#ifdef CONFIG_TIPC_CRYPTO
/* TX crypto handler */
struct tipc_crypto *crypto_tx;
#endif
/* Work item for net finalize */
struct tipc_net_work final_work;
};
static inline struct tipc_net *tipc_net(struct net *net)
{
return net_generic(net, tipc_net_id);
}
static inline int tipc_netid(struct net *net)
{
return tipc_net(net)->net_id;
}
static inline struct list_head *tipc_nodes(struct net *net)
{
return &tipc_net(net)->node_list;
}
static inline struct name_table *tipc_name_table(struct net *net)
{
return tipc_net(net)->nametbl;
}
static inline struct tipc_topsrv *tipc_topsrv(struct net *net)
{
return tipc_net(net)->topsrv;
}
static inline unsigned int tipc_hashfn(u32 addr)
{
return addr & (NODE_HTABLE_SIZE - 1);
}
static inline u16 mod(u16 x)
{
return x & 0xffffu;
}
static inline int less_eq(u16 left, u16 right)
{
return mod(right - left) < 32768u;
}
static inline int more(u16 left, u16 right)
{
return !less_eq(left, right);
}
static inline int less(u16 left, u16 right)
{
return less_eq(left, right) && (mod(right) != mod(left));
}
static inline int in_range(u16 val, u16 min, u16 max)
{
return !less(val, min) && !more(val, max);
}
static inline u32 tipc_net_hash_mixes(struct net *net, int tn_rand)
{
return net_hash_mix(&init_net) ^ net_hash_mix(net) ^ tn_rand;
}
#ifdef CONFIG_SYSCTL
int tipc_register_sysctl(void);
void tipc_unregister_sysctl(void);
#else
#define tipc_register_sysctl() 0
#define tipc_unregister_sysctl()
#endif
#endif