Re: [PATCH] net: Fix __inet_inherit_port() to correctly increment bsockets and num_owners

[Eric Dumazet <eric.dumazet@gmail.com>]

Le jeudi 25 novembre 2010 à 21:09 -0800, Nagendra Tomar a écrit :
> inet sockets corresponding to passive connections are added to the bind hash
> using ___inet_inherit_port(). These sockets are later removed from the bind 
> hash using __inet_put_port(). These two functions are not exactly symmetrical. 
> __inet_put_port() decrements hashinfo->bsockets and tb->num_owners, whereas 
> ___inet_inherit_port() does not increment them. This results in both of these 
> going to -ve values.
> 
> This patch fixes this by calling inet_bind_hash() from ___inet_inherit_port(),
> which does the right thing.
> 
> Signed-off-by: Nagendra Singh Tomar <tomer_iisc@yahoo.com>
> 
> ---
> --- linux-2.6.36.1/net/ipv4/inet_hashtables.c.orig	2010-11-25 14:56:37.902456597 -0500
> +++ linux-2.6.36.1/net/ipv4/inet_hashtables.c	2010-11-25 15:44:15.038403317 -0500
> @@ -107,12 +107,10 @@ void __inet_inherit_port(struct sock *sk
>  	const int bhash = inet_bhashfn(sock_net(sk), inet_sk(child)->inet_num,
>  			table->bhash_size);
>  	struct inet_bind_hashbucket *head = &table->bhash[bhash];
> -	struct inet_bind_bucket *tb;
>  
>  	spin_lock(&head->lock);
> -	tb = inet_csk(sk)->icsk_bind_hash;
> -	sk_add_bind_node(child, &tb->owners);
> -	inet_csk(child)->icsk_bind_hash = tb;
> +	inet_bind_hash(child, inet_csk(sk)->icsk_bind_hash, 
> +			inet_sk(child)->inet_num);
>  	spin_unlock(&head->lock);
>  }
>  EXPORT_SYMBOL_GPL(__inet_inherit_port);
> ---
> 

Interesting, how did you notice it is wrong ?