* [PATCH net-next 1/2] tipc: fix potential deadlock when all links are reset
2015-03-26 10:10 [PATCH net-next 0/2] tipc: fix two corner issues Ying Xue
@ 2015-03-26 10:10 ` Ying Xue
2015-03-26 10:10 ` [PATCH net-next 2/2] tipc: involve reference counter for node structure Ying Xue
2015-03-29 19:41 ` [PATCH net-next 0/2] tipc: fix two corner issues David Miller
2 siblings, 0 replies; 4+ messages in thread
From: Ying Xue @ 2015-03-26 10:10 UTC (permalink / raw)
To: davem; +Cc: jon.maloy, netdev, tipc-discussion
[ 60.988363] ======================================================
[ 60.988754] [ INFO: possible circular locking dependency detected ]
[ 60.989152] 3.19.0+ #194 Not tainted
[ 60.989377] -------------------------------------------------------
[ 60.989781] swapper/3/0 is trying to acquire lock:
[ 60.990079] (&(&n_ptr->lock)->rlock){+.-...}, at: [<ffffffffa0006dca>] tipc_link_retransmit+0x1aa/0x240 [tipc]
[ 60.990743]
[ 60.990743] but task is already holding lock:
[ 60.991106] (&(&bclink->lock)->rlock){+.-...}, at: [<ffffffffa00004be>] tipc_bclink_lock+0x8e/0xa0 [tipc]
[ 60.991738]
[ 60.991738] which lock already depends on the new lock.
[ 60.991738]
[ 60.992174]
[ 60.992174] the existing dependency chain (in reverse order) is:
[ 60.992174]
-> #1 (&(&bclink->lock)->rlock){+.-...}:
[ 60.992174] [<ffffffff810a9c0c>] lock_acquire+0x9c/0x140
[ 60.992174] [<ffffffff8179c41f>] _raw_spin_lock_bh+0x3f/0x50
[ 60.992174] [<ffffffffa00004be>] tipc_bclink_lock+0x8e/0xa0 [tipc]
[ 60.992174] [<ffffffffa0000f57>] tipc_bclink_add_node+0x97/0xf0 [tipc]
[ 60.992174] [<ffffffffa0011815>] tipc_node_link_up+0xf5/0x110 [tipc]
[ 60.992174] [<ffffffffa0007783>] link_state_event+0x2b3/0x4f0 [tipc]
[ 60.992174] [<ffffffffa00193c0>] tipc_link_proto_rcv+0x24c/0x418 [tipc]
[ 60.992174] [<ffffffffa0008857>] tipc_rcv+0x827/0xac0 [tipc]
[ 60.992174] [<ffffffffa0002ca3>] tipc_l2_rcv_msg+0x73/0xd0 [tipc]
[ 60.992174] [<ffffffff81646e66>] __netif_receive_skb_core+0x746/0x980
[ 60.992174] [<ffffffff816470c1>] __netif_receive_skb+0x21/0x70
[ 60.992174] [<ffffffff81647295>] netif_receive_skb_internal+0x35/0x130
[ 60.992174] [<ffffffff81648218>] napi_gro_receive+0x158/0x1d0
[ 60.992174] [<ffffffff81559e05>] e1000_clean_rx_irq+0x155/0x490
[ 60.992174] [<ffffffff8155c1b7>] e1000_clean+0x267/0x990
[ 60.992174] [<ffffffff81647b60>] net_rx_action+0x150/0x360
[ 60.992174] [<ffffffff8105ec43>] __do_softirq+0x123/0x360
[ 60.992174] [<ffffffff8105f12e>] irq_exit+0x8e/0xb0
[ 60.992174] [<ffffffff8179f9f5>] do_IRQ+0x65/0x110
[ 60.992174] [<ffffffff8179da6f>] ret_from_intr+0x0/0x13
[ 60.992174] [<ffffffff8100de9f>] arch_cpu_idle+0xf/0x20
[ 60.992174] [<ffffffff8109dfa6>] cpu_startup_entry+0x2f6/0x3f0
[ 60.992174] [<ffffffff81033cda>] start_secondary+0x13a/0x150
[ 60.992174]
-> #0 (&(&n_ptr->lock)->rlock){+.-...}:
[ 60.992174] [<ffffffff810a8f7d>] __lock_acquire+0x163d/0x1ca0
[ 60.992174] [<ffffffff810a9c0c>] lock_acquire+0x9c/0x140
[ 60.992174] [<ffffffff8179c41f>] _raw_spin_lock_bh+0x3f/0x50
[ 60.992174] [<ffffffffa0006dca>] tipc_link_retransmit+0x1aa/0x240 [tipc]
[ 60.992174] [<ffffffffa0001e11>] tipc_bclink_rcv+0x611/0x640 [tipc]
[ 60.992174] [<ffffffffa0008646>] tipc_rcv+0x616/0xac0 [tipc]
[ 60.992174] [<ffffffffa0002ca3>] tipc_l2_rcv_msg+0x73/0xd0 [tipc]
[ 60.992174] [<ffffffff81646e66>] __netif_receive_skb_core+0x746/0x980
[ 60.992174] [<ffffffff816470c1>] __netif_receive_skb+0x21/0x70
[ 60.992174] [<ffffffff81647295>] netif_receive_skb_internal+0x35/0x130
[ 60.992174] [<ffffffff81648218>] napi_gro_receive+0x158/0x1d0
[ 60.992174] [<ffffffff81559e05>] e1000_clean_rx_irq+0x155/0x490
[ 60.992174] [<ffffffff8155c1b7>] e1000_clean+0x267/0x990
[ 60.992174] [<ffffffff81647b60>] net_rx_action+0x150/0x360
[ 60.992174] [<ffffffff8105ec43>] __do_softirq+0x123/0x360
[ 60.992174] [<ffffffff8105f12e>] irq_exit+0x8e/0xb0
[ 60.992174] [<ffffffff8179f9f5>] do_IRQ+0x65/0x110
[ 60.992174] [<ffffffff8179da6f>] ret_from_intr+0x0/0x13
[ 60.992174] [<ffffffff8100de9f>] arch_cpu_idle+0xf/0x20
[ 60.992174] [<ffffffff8109dfa6>] cpu_startup_entry+0x2f6/0x3f0
[ 60.992174] [<ffffffff81033cda>] start_secondary+0x13a/0x150
[ 60.992174]
[ 60.992174] other info that might help us debug this:
[ 60.992174]
[ 60.992174] Possible unsafe locking scenario:
[ 60.992174]
[ 60.992174] CPU0 CPU1
[ 60.992174] ---- ----
[ 60.992174] lock(&(&bclink->lock)->rlock);
[ 60.992174] lock(&(&n_ptr->lock)->rlock);
[ 60.992174] lock(&(&bclink->lock)->rlock);
[ 60.992174] lock(&(&n_ptr->lock)->rlock);
[ 60.992174]
[ 60.992174] *** DEADLOCK ***
[ 60.992174]
[ 60.992174] 3 locks held by swapper/3/0:
[ 60.992174] #0: (rcu_read_lock){......}, at: [<ffffffff81646791>] __netif_receive_skb_core+0x71/0x980
[ 60.992174] #1: (rcu_read_lock){......}, at: [<ffffffffa0002c35>] tipc_l2_rcv_msg+0x5/0xd0 [tipc]
[ 60.992174] #2: (&(&bclink->lock)->rlock){+.-...}, at: [<ffffffffa00004be>] tipc_bclink_lock+0x8e/0xa0 [tipc]
[ 60.992174]
The correct the sequence of grabbing n_ptr->lock and bclink->lock
should be that the former is first held and the latter is then taken,
which exactly happened on CPU1. But especially when the retransmission
of broadcast link is failed, bclink->lock is first held in
tipc_bclink_rcv(), and n_ptr->lock is taken in link_retransmit_failure()
called by tipc_link_retransmit() subsequently, which is demonstrated on
CPU0. As a result, deadlock occurs.
If the order of holding the two locks happening on CPU0 is reversed, the
deadlock risk will be relieved. Therefore, the node lock taken in
link_retransmit_failure() originally is moved to tipc_bclink_rcv()
so that it's obtained before bclink lock. But the precondition of
the adjustment of node lock is that responding to bclink reset event
must be moved from tipc_bclink_unlock() to tipc_node_unlock().
Reviewed-by: Erik Hugne <erik.hugne@ericsson.com>
Signed-off-by: Ying Xue <ying.xue@windriver.com>
---
net/tipc/bcast.c | 23 +----------------------
net/tipc/bcast.h | 4 ----
net/tipc/link.c | 5 +----
net/tipc/node.c | 5 ++++-
net/tipc/node.h | 3 ++-
5 files changed, 8 insertions(+), 32 deletions(-)
diff --git a/net/tipc/bcast.c b/net/tipc/bcast.c
index 7935553..4289dd6 100644
--- a/net/tipc/bcast.c
+++ b/net/tipc/bcast.c
@@ -62,21 +62,8 @@ static void tipc_bclink_lock(struct net *net)
static void tipc_bclink_unlock(struct net *net)
{
struct tipc_net *tn = net_generic(net, tipc_net_id);
- struct tipc_node *node = NULL;
- if (likely(!tn->bclink->flags)) {
- spin_unlock_bh(&tn->bclink->lock);
- return;
- }
-
- if (tn->bclink->flags & TIPC_BCLINK_RESET) {
- tn->bclink->flags &= ~TIPC_BCLINK_RESET;
- node = tipc_bclink_retransmit_to(net);
- }
spin_unlock_bh(&tn->bclink->lock);
-
- if (node)
- tipc_link_reset_all(node);
}
void tipc_bclink_input(struct net *net)
@@ -91,13 +78,6 @@ uint tipc_bclink_get_mtu(void)
return MAX_PKT_DEFAULT_MCAST;
}
-void tipc_bclink_set_flags(struct net *net, unsigned int flags)
-{
- struct tipc_net *tn = net_generic(net, tipc_net_id);
-
- tn->bclink->flags |= flags;
-}
-
static u32 bcbuf_acks(struct sk_buff *buf)
{
return (u32)(unsigned long)TIPC_SKB_CB(buf)->handle;
@@ -156,7 +136,6 @@ static void bclink_update_last_sent(struct tipc_node *node, u32 seqno)
seqno : node->bclink.last_sent;
}
-
/**
* tipc_bclink_retransmit_to - get most recent node to request retransmission
*
@@ -476,13 +455,13 @@ void tipc_bclink_rcv(struct net *net, struct sk_buff *buf)
goto unlock;
if (msg_destnode(msg) == tn->own_addr) {
tipc_bclink_acknowledge(node, msg_bcast_ack(msg));
- tipc_node_unlock(node);
tipc_bclink_lock(net);
bcl->stats.recv_nacks++;
tn->bclink->retransmit_to = node;
bclink_retransmit_pkt(tn, msg_bcgap_after(msg),
msg_bcgap_to(msg));
tipc_bclink_unlock(net);
+ tipc_node_unlock(node);
} else {
tipc_node_unlock(node);
bclink_peek_nack(net, msg);
diff --git a/net/tipc/bcast.h b/net/tipc/bcast.h
index 43f397f..4bdc122 100644
--- a/net/tipc/bcast.h
+++ b/net/tipc/bcast.h
@@ -55,7 +55,6 @@ struct tipc_bcbearer_pair {
struct tipc_bearer *secondary;
};
-#define TIPC_BCLINK_RESET 1
#define BCBEARER MAX_BEARERS
/**
@@ -86,7 +85,6 @@ struct tipc_bcbearer {
* @lock: spinlock governing access to structure
* @link: (non-standard) broadcast link structure
* @node: (non-standard) node structure representing b'cast link's peer node
- * @flags: represent bclink states
* @bcast_nodes: map of broadcast-capable nodes
* @retransmit_to: node that most recently requested a retransmit
*
@@ -96,7 +94,6 @@ struct tipc_bclink {
spinlock_t lock;
struct tipc_link link;
struct tipc_node node;
- unsigned int flags;
struct sk_buff_head arrvq;
struct sk_buff_head inputq;
struct tipc_node_map bcast_nodes;
@@ -117,7 +114,6 @@ static inline int tipc_nmap_equal(struct tipc_node_map *nm_a,
int tipc_bclink_init(struct net *net);
void tipc_bclink_stop(struct net *net);
-void tipc_bclink_set_flags(struct net *tn, unsigned int flags);
void tipc_bclink_add_node(struct net *net, u32 addr);
void tipc_bclink_remove_node(struct net *net, u32 addr);
struct tipc_node *tipc_bclink_retransmit_to(struct net *tn);
diff --git a/net/tipc/link.c b/net/tipc/link.c
index 1287161..f5e086c 100644
--- a/net/tipc/link.c
+++ b/net/tipc/link.c
@@ -980,7 +980,6 @@ static void link_retransmit_failure(struct tipc_link *l_ptr,
(unsigned long) TIPC_SKB_CB(buf)->handle);
n_ptr = tipc_bclink_retransmit_to(net);
- tipc_node_lock(n_ptr);
tipc_addr_string_fill(addr_string, n_ptr->addr);
pr_info("Broadcast link info for %s\n", addr_string);
@@ -992,9 +991,7 @@ static void link_retransmit_failure(struct tipc_link *l_ptr,
n_ptr->bclink.oos_state,
n_ptr->bclink.last_sent);
- tipc_node_unlock(n_ptr);
-
- tipc_bclink_set_flags(net, TIPC_BCLINK_RESET);
+ n_ptr->action_flags |= TIPC_BCAST_RESET;
l_ptr->stale_count = 0;
}
}
diff --git a/net/tipc/node.c b/net/tipc/node.c
index 26d1de1..5cc43d3 100644
--- a/net/tipc/node.c
+++ b/net/tipc/node.c
@@ -459,7 +459,7 @@ void tipc_node_unlock(struct tipc_node *node)
TIPC_NOTIFY_NODE_DOWN | TIPC_NOTIFY_NODE_UP |
TIPC_NOTIFY_LINK_DOWN | TIPC_NOTIFY_LINK_UP |
TIPC_WAKEUP_BCAST_USERS | TIPC_BCAST_MSG_EVT |
- TIPC_NAMED_MSG_EVT);
+ TIPC_NAMED_MSG_EVT | TIPC_BCAST_RESET);
spin_unlock_bh(&node->lock);
@@ -488,6 +488,9 @@ void tipc_node_unlock(struct tipc_node *node)
if (flags & TIPC_BCAST_MSG_EVT)
tipc_bclink_input(net);
+
+ if (flags & TIPC_BCAST_RESET)
+ tipc_link_reset_all(node);
}
/* Caller should hold node lock for the passed node */
diff --git a/net/tipc/node.h b/net/tipc/node.h
index e89ac04..9629ecd 100644
--- a/net/tipc/node.h
+++ b/net/tipc/node.h
@@ -64,7 +64,8 @@ enum {
TIPC_NOTIFY_LINK_UP = (1 << 6),
TIPC_NOTIFY_LINK_DOWN = (1 << 7),
TIPC_NAMED_MSG_EVT = (1 << 8),
- TIPC_BCAST_MSG_EVT = (1 << 9)
+ TIPC_BCAST_MSG_EVT = (1 << 9),
+ TIPC_BCAST_RESET = (1 << 10)
};
/**
--
1.7.9.5
------------------------------------------------------------------------------
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^ permalink raw reply related [flat|nested] 4+ messages in thread* [PATCH net-next 2/2] tipc: involve reference counter for node structure
2015-03-26 10:10 [PATCH net-next 0/2] tipc: fix two corner issues Ying Xue
2015-03-26 10:10 ` [PATCH net-next 1/2] tipc: fix potential deadlock when all links are reset Ying Xue
@ 2015-03-26 10:10 ` Ying Xue
2015-03-29 19:41 ` [PATCH net-next 0/2] tipc: fix two corner issues David Miller
2 siblings, 0 replies; 4+ messages in thread
From: Ying Xue @ 2015-03-26 10:10 UTC (permalink / raw)
To: davem; +Cc: jon.maloy, netdev, tipc-discussion
TIPC node hash node table is protected with rcu lock on read side.
tipc_node_find() is used to look for a node object with node address
through iterating the hash node table. As the entire process of what
tipc_node_find() traverses the table is guarded with rcu read lock,
it's safe for us. However, when callers use the node object returned
by tipc_node_find(), there is no rcu read lock applied. Therefore,
this is absolutely unsafe for callers of tipc_node_find().
Now we introduce a reference counter for node structure. Before
tipc_node_find() returns node object to its caller, it first increases
the reference counter. Accordingly, after its caller used it up,
it decreases the counter again. This can prevent a node being used by
one thread from being freed by another thread.
Reviewed-by: Erik Hugne <erik.hugne@ericsson.com>
Reviewed-by: Jon Maloy <jon.maloy@ericson.com>
Signed-off-by: Ying Xue <ying.xue@windriver.com>
---
net/tipc/bcast.c | 5 +--
net/tipc/discover.c | 1 +
net/tipc/link.c | 7 ++--
net/tipc/name_distr.c | 2 ++
net/tipc/node.c | 85 +++++++++++++++++++++++++++++++++++--------------
net/tipc/node.h | 9 ++++--
6 files changed, 79 insertions(+), 30 deletions(-)
diff --git a/net/tipc/bcast.c b/net/tipc/bcast.c
index 4289dd6..ae558dd 100644
--- a/net/tipc/bcast.c
+++ b/net/tipc/bcast.c
@@ -329,13 +329,12 @@ static void bclink_peek_nack(struct net *net, struct tipc_msg *msg)
return;
tipc_node_lock(n_ptr);
-
if (n_ptr->bclink.recv_permitted &&
(n_ptr->bclink.last_in != n_ptr->bclink.last_sent) &&
(n_ptr->bclink.last_in == msg_bcgap_after(msg)))
n_ptr->bclink.oos_state = 2;
-
tipc_node_unlock(n_ptr);
+ tipc_node_put(n_ptr);
}
/* tipc_bclink_xmit - deliver buffer chain to all nodes in cluster
@@ -466,6 +465,7 @@ void tipc_bclink_rcv(struct net *net, struct sk_buff *buf)
tipc_node_unlock(node);
bclink_peek_nack(net, msg);
}
+ tipc_node_put(node);
goto exit;
}
@@ -570,6 +570,7 @@ receive:
unlock:
tipc_node_unlock(node);
+ tipc_node_put(node);
exit:
kfree_skb(buf);
}
diff --git a/net/tipc/discover.c b/net/tipc/discover.c
index 169f3dd..967e292 100644
--- a/net/tipc/discover.c
+++ b/net/tipc/discover.c
@@ -260,6 +260,7 @@ void tipc_disc_rcv(struct net *net, struct sk_buff *buf,
}
}
tipc_node_unlock(node);
+ tipc_node_put(node);
}
/**
diff --git a/net/tipc/link.c b/net/tipc/link.c
index f5e086c..514466e 100644
--- a/net/tipc/link.c
+++ b/net/tipc/link.c
@@ -854,6 +854,7 @@ int tipc_link_xmit(struct net *net, struct sk_buff_head *list, u32 dnode,
if (link)
rc = __tipc_link_xmit(net, link, list);
tipc_node_unlock(node);
+ tipc_node_put(node);
}
if (link)
return rc;
@@ -1116,8 +1117,8 @@ void tipc_rcv(struct net *net, struct sk_buff *skb, struct tipc_bearer *b_ptr)
n_ptr = tipc_node_find(net, msg_prevnode(msg));
if (unlikely(!n_ptr))
goto discard;
- tipc_node_lock(n_ptr);
+ tipc_node_lock(n_ptr);
/* Locate unicast link endpoint that should handle message */
l_ptr = n_ptr->links[b_ptr->identity];
if (unlikely(!l_ptr))
@@ -1205,6 +1206,7 @@ void tipc_rcv(struct net *net, struct sk_buff *skb, struct tipc_bearer *b_ptr)
skb = NULL;
unlock:
tipc_node_unlock(n_ptr);
+ tipc_node_put(n_ptr);
discard:
if (unlikely(skb))
kfree_skb(skb);
@@ -2236,7 +2238,6 @@ int tipc_nl_link_dump(struct sk_buff *skb, struct netlink_callback *cb)
msg.seq = cb->nlh->nlmsg_seq;
rcu_read_lock();
-
if (prev_node) {
node = tipc_node_find(net, prev_node);
if (!node) {
@@ -2249,6 +2250,7 @@ int tipc_nl_link_dump(struct sk_buff *skb, struct netlink_callback *cb)
cb->prev_seq = 1;
goto out;
}
+ tipc_node_put(node);
list_for_each_entry_continue_rcu(node, &tn->node_list,
list) {
@@ -2256,6 +2258,7 @@ int tipc_nl_link_dump(struct sk_buff *skb, struct netlink_callback *cb)
err = __tipc_nl_add_node_links(net, &msg, node,
&prev_link);
tipc_node_unlock(node);
+ tipc_node_put(node);
if (err)
goto out;
diff --git a/net/tipc/name_distr.c b/net/tipc/name_distr.c
index 506aaa5..41e7b7e 100644
--- a/net/tipc/name_distr.c
+++ b/net/tipc/name_distr.c
@@ -244,6 +244,7 @@ static void tipc_publ_subscribe(struct net *net, struct publication *publ,
tipc_node_lock(node);
list_add_tail(&publ->nodesub_list, &node->publ_list);
tipc_node_unlock(node);
+ tipc_node_put(node);
}
static void tipc_publ_unsubscribe(struct net *net, struct publication *publ,
@@ -258,6 +259,7 @@ static void tipc_publ_unsubscribe(struct net *net, struct publication *publ,
tipc_node_lock(node);
list_del_init(&publ->nodesub_list);
tipc_node_unlock(node);
+ tipc_node_put(node);
}
/**
diff --git a/net/tipc/node.c b/net/tipc/node.c
index 5cc43d3..3e4f048 100644
--- a/net/tipc/node.c
+++ b/net/tipc/node.c
@@ -42,6 +42,7 @@
static void node_lost_contact(struct tipc_node *n_ptr);
static void node_established_contact(struct tipc_node *n_ptr);
+static void tipc_node_delete(struct tipc_node *node);
struct tipc_sock_conn {
u32 port;
@@ -67,6 +68,23 @@ static unsigned int tipc_hashfn(u32 addr)
return addr & (NODE_HTABLE_SIZE - 1);
}
+static void tipc_node_kref_release(struct kref *kref)
+{
+ struct tipc_node *node = container_of(kref, struct tipc_node, kref);
+
+ tipc_node_delete(node);
+}
+
+void tipc_node_put(struct tipc_node *node)
+{
+ kref_put(&node->kref, tipc_node_kref_release);
+}
+
+static void tipc_node_get(struct tipc_node *node)
+{
+ kref_get(&node->kref);
+}
+
/*
* tipc_node_find - locate specified node object, if it exists
*/
@@ -82,6 +100,7 @@ struct tipc_node *tipc_node_find(struct net *net, u32 addr)
hlist_for_each_entry_rcu(node, &tn->node_htable[tipc_hashfn(addr)],
hash) {
if (node->addr == addr) {
+ tipc_node_get(node);
rcu_read_unlock();
return node;
}
@@ -106,6 +125,7 @@ struct tipc_node *tipc_node_create(struct net *net, u32 addr)
}
n_ptr->addr = addr;
n_ptr->net = net;
+ kref_init(&n_ptr->kref);
spin_lock_init(&n_ptr->lock);
INIT_HLIST_NODE(&n_ptr->hash);
INIT_LIST_HEAD(&n_ptr->list);
@@ -120,16 +140,17 @@ struct tipc_node *tipc_node_create(struct net *net, u32 addr)
list_add_tail_rcu(&n_ptr->list, &temp_node->list);
n_ptr->action_flags = TIPC_WAIT_PEER_LINKS_DOWN;
n_ptr->signature = INVALID_NODE_SIG;
+ tipc_node_get(n_ptr);
exit:
spin_unlock_bh(&tn->node_list_lock);
return n_ptr;
}
-static void tipc_node_delete(struct tipc_net *tn, struct tipc_node *n_ptr)
+static void tipc_node_delete(struct tipc_node *node)
{
- list_del_rcu(&n_ptr->list);
- hlist_del_rcu(&n_ptr->hash);
- kfree_rcu(n_ptr, rcu);
+ list_del_rcu(&node->list);
+ hlist_del_rcu(&node->hash);
+ kfree_rcu(node, rcu);
}
void tipc_node_stop(struct net *net)
@@ -139,7 +160,7 @@ void tipc_node_stop(struct net *net)
spin_lock_bh(&tn->node_list_lock);
list_for_each_entry_safe(node, t_node, &tn->node_list, list)
- tipc_node_delete(tn, node);
+ tipc_node_put(node);
spin_unlock_bh(&tn->node_list_lock);
}
@@ -147,6 +168,7 @@ int tipc_node_add_conn(struct net *net, u32 dnode, u32 port, u32 peer_port)
{
struct tipc_node *node;
struct tipc_sock_conn *conn;
+ int err = 0;
if (in_own_node(net, dnode))
return 0;
@@ -157,8 +179,10 @@ int tipc_node_add_conn(struct net *net, u32 dnode, u32 port, u32 peer_port)
return -EHOSTUNREACH;
}
conn = kmalloc(sizeof(*conn), GFP_ATOMIC);
- if (!conn)
- return -EHOSTUNREACH;
+ if (!conn) {
+ err = -EHOSTUNREACH;
+ goto exit;
+ }
conn->peer_node = dnode;
conn->port = port;
conn->peer_port = peer_port;
@@ -166,7 +190,9 @@ int tipc_node_add_conn(struct net *net, u32 dnode, u32 port, u32 peer_port)
tipc_node_lock(node);
list_add_tail(&conn->list, &node->conn_sks);
tipc_node_unlock(node);
- return 0;
+exit:
+ tipc_node_put(node);
+ return err;
}
void tipc_node_remove_conn(struct net *net, u32 dnode, u32 port)
@@ -189,6 +215,7 @@ void tipc_node_remove_conn(struct net *net, u32 dnode, u32 port)
kfree(conn);
}
tipc_node_unlock(node);
+ tipc_node_put(node);
}
/**
@@ -417,19 +444,25 @@ int tipc_node_get_linkname(struct net *net, u32 bearer_id, u32 addr,
char *linkname, size_t len)
{
struct tipc_link *link;
+ int err = -EINVAL;
struct tipc_node *node = tipc_node_find(net, addr);
- if ((bearer_id >= MAX_BEARERS) || !node)
- return -EINVAL;
+ if (!node)
+ return err;
+
+ if (bearer_id >= MAX_BEARERS)
+ goto exit;
+
tipc_node_lock(node);
link = node->links[bearer_id];
if (link) {
strncpy(linkname, link->name, len);
- tipc_node_unlock(node);
- return 0;
+ err = 0;
}
+exit:
tipc_node_unlock(node);
- return -EINVAL;
+ tipc_node_put(node);
+ return err;
}
void tipc_node_unlock(struct tipc_node *node)
@@ -545,17 +578,21 @@ int tipc_nl_node_dump(struct sk_buff *skb, struct netlink_callback *cb)
msg.seq = cb->nlh->nlmsg_seq;
rcu_read_lock();
-
- if (last_addr && !tipc_node_find(net, last_addr)) {
- rcu_read_unlock();
- /* We never set seq or call nl_dump_check_consistent() this
- * means that setting prev_seq here will cause the consistence
- * check to fail in the netlink callback handler. Resulting in
- * the NLMSG_DONE message having the NLM_F_DUMP_INTR flag set if
- * the node state changed while we released the lock.
- */
- cb->prev_seq = 1;
- return -EPIPE;
+ if (last_addr) {
+ node = tipc_node_find(net, last_addr);
+ if (!node) {
+ rcu_read_unlock();
+ /* We never set seq or call nl_dump_check_consistent()
+ * this means that setting prev_seq here will cause the
+ * consistence check to fail in the netlink callback
+ * handler. Resulting in the NLMSG_DONE message having
+ * the NLM_F_DUMP_INTR flag set if the node state
+ * changed while we released the lock.
+ */
+ cb->prev_seq = 1;
+ return -EPIPE;
+ }
+ tipc_node_put(node);
}
list_for_each_entry_rcu(node, &tn->node_list, list) {
diff --git a/net/tipc/node.h b/net/tipc/node.h
index 9629ecd..02d5c20 100644
--- a/net/tipc/node.h
+++ b/net/tipc/node.h
@@ -94,6 +94,7 @@ struct tipc_node_bclink {
/**
* struct tipc_node - TIPC node structure
* @addr: network address of node
+ * @ref: reference counter to node object
* @lock: spinlock governing access to structure
* @net: the applicable net namespace
* @hash: links to adjacent nodes in unsorted hash chain
@@ -115,6 +116,7 @@ struct tipc_node_bclink {
*/
struct tipc_node {
u32 addr;
+ struct kref kref;
spinlock_t lock;
struct net *net;
struct hlist_node hash;
@@ -137,6 +139,7 @@ struct tipc_node {
};
struct tipc_node *tipc_node_find(struct net *net, u32 addr);
+void tipc_node_put(struct tipc_node *node);
struct tipc_node *tipc_node_create(struct net *net, u32 addr);
void tipc_node_stop(struct net *net);
void tipc_node_attach_link(struct tipc_node *n_ptr, struct tipc_link *l_ptr);
@@ -171,10 +174,12 @@ static inline uint tipc_node_get_mtu(struct net *net, u32 addr, u32 selector)
node = tipc_node_find(net, addr);
- if (likely(node))
+ if (likely(node)) {
mtu = node->act_mtus[selector & 1];
- else
+ tipc_node_put(node);
+ } else {
mtu = MAX_MSG_SIZE;
+ }
return mtu;
}
--
1.7.9.5
------------------------------------------------------------------------------
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