tipc: fix deadlock during socket release

A deadlock might occur if name table is withdrawn in socket release
routine, and while packets are still being received from bearer.

       CPU0                       CPU1
T0:   recv_msg()               release()
T1:   tipc_recv_msg()          tipc_withdraw()
T2:   [grab node lock]         [grab port lock]
T3:   tipc_link_wakeup_ports() tipc_nametbl_withdraw()
T4:   [grab port lock]*        named_cluster_distribute()
T5:   wakeupdispatch()         tipc_link_send()
T6:                            [grab node lock]*

The opposite order of holding port lock and node lock on above two
different paths may result in a deadlock. If socket lock instead of
port lock is used to protect port instance in tipc_withdraw(), the
reverse order of holding port lock and node lock will be eliminated,
as a result, the deadlock is killed as well.

Reported-by: Lars Everbrand <lars.everbrand@ericsson.com>
Reviewed-by: Erik Hugne <erik.hugne@ericsson.com>
Signed-off-by: Ying Xue <ying.xue@windriver.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 15 insertions, 30 deletions

diff --git a/net/tipc/port.c b/net/tipc/port.c
index c081a7632302..d43f3182b1d4 100644
--- a/net/tipc/port.c
+++ b/net/tipc/port.c
@@ -251,18 +251,15 @@ struct tipc_port *tipc_createport(struct sock *sk,
 	return p_ptr;
 }
 
-int tipc_deleteport(u32 ref)
+int tipc_deleteport(struct tipc_port *p_ptr)
 {
-	struct tipc_port *p_ptr;
 	struct sk_buff *buf = NULL;
 
-	tipc_withdraw(ref, 0, NULL);
-	p_ptr = tipc_port_lock(ref);
-	if (!p_ptr)
-		return -EINVAL;
+	tipc_withdraw(p_ptr, 0, NULL);
 
-	tipc_ref_discard(ref);
-	tipc_port_unlock(p_ptr);
+	spin_lock_bh(p_ptr->lock);
+	tipc_ref_discard(p_ptr->ref);
+	spin_unlock_bh(p_ptr->lock);
 
 	k_cancel_timer(&p_ptr->timer);
 	if (p_ptr->connected) {
@@ -704,47 +701,36 @@ int tipc_set_portimportance(u32 ref, unsigned int imp)
 }
 
 
-int tipc_publish(u32 ref, unsigned int scope, struct tipc_name_seq const *seq)
+int tipc_publish(struct tipc_port *p_ptr, unsigned int scope,
+		 struct tipc_name_seq const *seq)
 {
-	struct tipc_port *p_ptr;
 	struct publication *publ;
 	u32 key;
-	int res = -EINVAL;
 
-	p_ptr = tipc_port_lock(ref);
-	if (!p_ptr)
+	if (p_ptr->connected)
 		return -EINVAL;
+	key = p_ptr->ref + p_ptr->pub_count + 1;
+	if (key == p_ptr->ref)
+		return -EADDRINUSE;
 
-	if (p_ptr->connected)
-		goto exit;
-	key = ref + p_ptr->pub_count + 1;
-	if (key == ref) {
-		res = -EADDRINUSE;
-		goto exit;
-	}
 	publ = tipc_nametbl_publish(seq->type, seq->lower, seq->upper,
 				    scope, p_ptr->ref, key);
 	if (publ) {
 		list_add(&publ->pport_list, &p_ptr->publications);
 		p_ptr->pub_count++;
 		p_ptr->published = 1;
-		res = 0;
+		return 0;
 	}
-exit:
-	tipc_port_unlock(p_ptr);
-	return res;
+	return -EINVAL;
 }
 
-int tipc_withdraw(u32 ref, unsigned int scope, struct tipc_name_seq const *seq)
+int tipc_withdraw(struct tipc_port *p_ptr, unsigned int scope,
+		  struct tipc_name_seq const *seq)
 {
-	struct tipc_port *p_ptr;
 	struct publication *publ;
 	struct publication *tpubl;
 	int res = -EINVAL;
 
-	p_ptr = tipc_port_lock(ref);
-	if (!p_ptr)
-		return -EINVAL;
 	if (!seq) {
 		list_for_each_entry_safe(publ, tpubl,
 					 &p_ptr->publications, pport_list) {
@@ -771,7 +757,6 @@ int tipc_withdraw(u32 ref, unsigned int scope, struct tipc_name_seq const *seq)
 	}
 	if (list_empty(&p_ptr->publications))
 		p_ptr->published = 0;
-	tipc_port_unlock(p_ptr);
 	return res;
 }