[PATCH -next] tipc: fix imbalance read_unlock_bh in __tipc_nl_add_monitor()

[PATCH -next] tipc: fix imbalance read_unlock_bh in __tipc_nl_add_monitor()

[Wei Yongjun]

In the error handling case of nla_nest_start() failed read_unlock_bh()
is called  to unlock a lock that had not been taken yet. sparse warns
about the context imbalance as the following:

net/tipc/monitor.c:799:23: warning:
 context imbalance in '__tipc_nl_add_monitor' - different lock contexts for basic block

Fixes: cf6f7e1d5109 ('tipc: dump monitor attributes')
Signed-off-by: Wei Yongjun <weiyj.lk@gmail.com>
---
 net/tipc/monitor.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/net/tipc/monitor.c b/net/tipc/monitor.c
index be70a57..b62caa1 100644
--- a/net/tipc/monitor.c
+++ b/net/tipc/monitor.c
@@ -794,10 +794,10 @@ int __tipc_nl_add_monitor(struct net *net, struct tipc_nl_msg *msg,
 	return 0;
 
 attr_msg_full:
+	read_unlock_bh(&mon->lock);
 	nla_nest_cancel(msg->skb, attrs);
 msg_full:
 	genlmsg_cancel(msg->skb, hdr);
-	read_unlock_bh(&mon->lock);
 
 	return -EMSGSIZE;
 }

Re: [PATCH -next] tipc: fix imbalance read_unlock_bh in __tipc_nl_add_monitor()

[Ying Xue]

On 07/28/2016 10:07 AM, Wei Yongjun wrote:
> In the error handling case of nla_nest_start() failed read_unlock_bh()
> is called  to unlock a lock that had not been taken yet. sparse warns
> about the context imbalance as the following:
> 
> net/tipc/monitor.c:799:23: warning:
>  context imbalance in '__tipc_nl_add_monitor' - different lock contexts for basic block
> 
> Fixes: cf6f7e1d5109 ('tipc: dump monitor attributes')
> Signed-off-by: Wei Yongjun <weiyj.lk@gmail.com>

Acked-by: Ying Xue <ying.xue@windriver.com>

> ---
>  net/tipc/monitor.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/net/tipc/monitor.c b/net/tipc/monitor.c
> index be70a57..b62caa1 100644
> --- a/net/tipc/monitor.c
> +++ b/net/tipc/monitor.c
> @@ -794,10 +794,10 @@ int __tipc_nl_add_monitor(struct net *net, struct tipc_nl_msg *msg,
>  	return 0;
>  
>  attr_msg_full:
> +	read_unlock_bh(&mon->lock);
>  	nla_nest_cancel(msg->skb, attrs);
>  msg_full:
>  	genlmsg_cancel(msg->skb, hdr);
> -	read_unlock_bh(&mon->lock);
>  
>  	return -EMSGSIZE;
>  }
> 
> 

Re: [PATCH -next] tipc: fix imbalance read_unlock_bh in __tipc_nl_add_monitor()

[David Miller]

From: Wei Yongjun <weiyj.lk@gmail.com>
Date: Thu, 28 Jul 2016 02:07:49 +0000

> In the error handling case of nla_nest_start() failed read_unlock_bh()
> is called  to unlock a lock that had not been taken yet. sparse warns
> about the context imbalance as the following:
> 
> net/tipc/monitor.c:799:23: warning:
>  context imbalance in '__tipc_nl_add_monitor' - different lock contexts for basic block
> 
> Fixes: cf6f7e1d5109 ('tipc: dump monitor attributes')
> Signed-off-by: Wei Yongjun <weiyj.lk@gmail.com>

Applied.