Locking dependency detected below possible unsafe locking scenario:
           CPU0                          CPU1
T0:  tipc_named_rcv()                tipc_rcv()
T1:  [grab nametble write lock]*     [grab node lock]*
T2:  tipc_update_nametbl()           tipc_node_link_up()
T3:  tipc_nodesub_subscribe()        tipc_nametbl_publish()
T4:  [grab node lock]*               [grab nametble write lock]*
The opposite order of holding nametbl write lock and node lock on
above two different paths may result in a deadlock. If we move the
the updating of the name table after link state named out of node
lock, the reverse order of holding locks will be eliminated, and
as a result, the deadlock risk.
Signed-off-by: Ying Xue <ying.xue@windriver.com>
Signed-off-by: Jon Maloy <jon.maloy@ericsson.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
		
	
			
		
			
				
	
	
		
			174 lines
		
	
	
	
		
			6.2 KiB
			
		
	
	
	
		
			C
		
	
	
	
	
	
			
		
		
	
	
			174 lines
		
	
	
	
		
			6.2 KiB
			
		
	
	
	
		
			C
		
	
	
	
	
	
/*
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 * net/tipc/node.h: Include file for TIPC node management routines
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 *
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 * Copyright (c) 2000-2006, Ericsson AB
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 * Copyright (c) 2005, 2010-2014, 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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#ifndef _TIPC_NODE_H
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#define _TIPC_NODE_H
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#include "node_subscr.h"
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#include "addr.h"
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#include "net.h"
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#include "bearer.h"
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#include "msg.h"
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/*
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 * Out-of-range value for node signature
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 */
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#define INVALID_NODE_SIG 0x10000
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/* Flags used to take different actions according to flag type
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 * TIPC_WAIT_PEER_LINKS_DOWN: wait to see that peer's links are down
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 * TIPC_WAIT_OWN_LINKS_DOWN: wait until peer node is declared down
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 * TIPC_NOTIFY_NODE_DOWN: notify node is down
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 * TIPC_NOTIFY_NODE_UP: notify node is up
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 * TIPC_DISTRIBUTE_NAME: publish or withdraw link state name type
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 */
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enum {
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	TIPC_WAIT_PEER_LINKS_DOWN	= (1 << 1),
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	TIPC_WAIT_OWN_LINKS_DOWN	= (1 << 2),
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	TIPC_NOTIFY_NODE_DOWN		= (1 << 3),
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	TIPC_NOTIFY_NODE_UP		= (1 << 4),
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	TIPC_WAKEUP_USERS		= (1 << 5),
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	TIPC_WAKEUP_BCAST_USERS		= (1 << 6),
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	TIPC_NOTIFY_LINK_UP		= (1 << 7),
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	TIPC_NOTIFY_LINK_DOWN		= (1 << 8)
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};
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/**
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 * struct tipc_node_bclink - TIPC node bclink structure
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 * @acked: sequence # of last outbound b'cast message acknowledged by node
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 * @last_in: sequence # of last in-sequence b'cast message received from node
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 * @last_sent: sequence # of last b'cast message sent by node
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 * @oos_state: state tracker for handling OOS b'cast messages
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 * @deferred_size: number of OOS b'cast messages in deferred queue
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 * @deferred_head: oldest OOS b'cast message received from node
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 * @deferred_tail: newest OOS b'cast message received from node
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 * @reasm_buf: broadcast reassembly queue head from node
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 * @recv_permitted: true if node is allowed to receive b'cast messages
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 */
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struct tipc_node_bclink {
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	u32 acked;
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	u32 last_in;
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	u32 last_sent;
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	u32 oos_state;
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	u32 deferred_size;
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	struct sk_buff *deferred_head;
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	struct sk_buff *deferred_tail;
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	struct sk_buff *reasm_buf;
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	bool recv_permitted;
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};
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/**
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 * struct tipc_node - TIPC node structure
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 * @addr: network address of node
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 * @lock: spinlock governing access to structure
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 * @hash: links to adjacent nodes in unsorted hash chain
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 * @active_links: pointers to active links to node
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 * @links: pointers to all links to node
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 * @action_flags: bit mask of different types of node actions
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 * @bclink: broadcast-related info
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 * @list: links to adjacent nodes in sorted list of cluster's nodes
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 * @working_links: number of working links to node (both active and standby)
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 * @link_cnt: number of links to node
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 * @signature: node instance identifier
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 * @link_id: local and remote bearer ids of changing link, if any
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 * @nsub: list of "node down" subscriptions monitoring node
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 * @rcu: rcu struct for tipc_node
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 */
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struct tipc_node {
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	u32 addr;
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	spinlock_t lock;
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	struct hlist_node hash;
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	struct tipc_link *active_links[2];
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	u32 act_mtus[2];
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	struct tipc_link *links[MAX_BEARERS];
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	unsigned int action_flags;
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	struct tipc_node_bclink bclink;
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	struct list_head list;
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	int link_cnt;
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	int working_links;
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	u32 signature;
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	u32 link_id;
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	struct list_head nsub;
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	struct sk_buff_head waiting_sks;
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	struct list_head conn_sks;
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	struct rcu_head rcu;
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};
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extern struct list_head tipc_node_list;
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struct tipc_node *tipc_node_find(u32 addr);
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struct tipc_node *tipc_node_create(u32 addr);
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void tipc_node_stop(void);
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void tipc_node_attach_link(struct tipc_node *n_ptr, struct tipc_link *l_ptr);
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void tipc_node_detach_link(struct tipc_node *n_ptr, struct tipc_link *l_ptr);
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void tipc_node_link_down(struct tipc_node *n_ptr, struct tipc_link *l_ptr);
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void tipc_node_link_up(struct tipc_node *n_ptr, struct tipc_link *l_ptr);
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int tipc_node_active_links(struct tipc_node *n_ptr);
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int tipc_node_is_up(struct tipc_node *n_ptr);
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struct sk_buff *tipc_node_get_links(const void *req_tlv_area, int req_tlv_space);
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struct sk_buff *tipc_node_get_nodes(const void *req_tlv_area, int req_tlv_space);
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int tipc_node_get_linkname(u32 bearer_id, u32 node, char *linkname, size_t len);
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void tipc_node_unlock(struct tipc_node *node);
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int tipc_node_add_conn(u32 dnode, u32 port, u32 peer_port);
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void tipc_node_remove_conn(u32 dnode, u32 port);
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static inline void tipc_node_lock(struct tipc_node *node)
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{
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	spin_lock_bh(&node->lock);
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}
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static inline bool tipc_node_blocked(struct tipc_node *node)
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{
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	return (node->action_flags & (TIPC_WAIT_PEER_LINKS_DOWN |
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		TIPC_NOTIFY_NODE_DOWN | TIPC_WAIT_OWN_LINKS_DOWN));
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}
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static inline uint tipc_node_get_mtu(u32 addr, u32 selector)
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{
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	struct tipc_node *node;
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	u32 mtu;
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	node = tipc_node_find(addr);
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	if (likely(node))
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		mtu = node->act_mtus[selector & 1];
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	else
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		mtu = MAX_MSG_SIZE;
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	return mtu;
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}
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#endif
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