Re: [PATCH 1/3] IPVS: Change of socket usage to enable name space exit.

[Simon Horman <horms@verge.net.au>]

On Tue, Apr 19, 2011 at 05:25:03PM +0200, Hans Schillstrom wrote:
> This is the first patch in a series of three.
> The cleanup doesn't work when not exit in a clean way by using ipvsadm.
> Killing of a namespace causes a hanging ipvs, this series will cure that.
> 
> If the sync daemons run in a namespace while it crashes
> or get killed, there is no way to stop them except for a reboot.
> 
> Kernel threads should not increment the use count of a socket.
> By calling sk_change_net() after creating a socket this is avoided.
> sock_release cant be used, instead sk_release_kernel() should be used.
> 
> Thanks to Eric W Biederman.
> 
> This patch is based on net-next-2.6  ver 2.6.39-rc2

Thanks Hans and Eric.

Is it only this 1st patch that is intended for 2.6.39?
The entire series feels a bit long to be applied
this late in the rc series.

In any case, I'll hold off for comment from Eric and Julian
before pushing any of these patches anywhere.

> Signed-off-by: Hans Schillstrom <hans@schillstrom.com>
> ---
>  net/netfilter/ipvs/ip_vs_sync.c |   28 +++++++++++++++++++---------
>  1 files changed, 19 insertions(+), 9 deletions(-)
> 
> diff --git a/net/netfilter/ipvs/ip_vs_sync.c b/net/netfilter/ipvs/ip_vs_sync.c
> index 3e7961e..3f87555 100644
> --- a/net/netfilter/ipvs/ip_vs_sync.c
> +++ b/net/netfilter/ipvs/ip_vs_sync.c
> @@ -1309,7 +1309,12 @@ static struct socket *make_send_sock(struct net *net)
>  		pr_err("Error during creation of socket; terminating\n");
>  		return ERR_PTR(result);
>  	}
> -
> +	/*
> +	 * Kernel sockets that are a part of a namespace, should not
> +	 * hold a reference to a namespace in order to allow to stop it.
> +	 * After sk_change_net should be released using sk_release_kernel.
> +	 */
> +	sk_change_net(sock->sk, net);
>  	result = set_mcast_if(sock->sk, ipvs->master_mcast_ifn);
>  	if (result < 0) {
>  		pr_err("Error setting outbound mcast interface\n");
> @@ -1334,8 +1339,8 @@ static struct socket *make_send_sock(struct net *net)
> 
>  	return sock;
> 
> -  error:
> -	sock_release(sock);
> +error:
> +	sk_release_kernel(sock->sk);
>  	return ERR_PTR(result);
>  }
> 
> @@ -1355,7 +1360,12 @@ static struct socket *make_receive_sock(struct net *net)
>  		pr_err("Error during creation of socket; terminating\n");
>  		return ERR_PTR(result);
>  	}
> -
> +	/*
> +	 * Kernel sockets that are a part of a namespace, should not
> +	 * hold a reference to a namespace in order to allow to stop it.
> +	 * After sk_change_net should be released using sk_release_kernel.
> +	 */
> +	sk_change_net(sock->sk, net);
>  	/* it is equivalent to the REUSEADDR option in user-space */
>  	sock->sk->sk_reuse = 1;
> 
> @@ -1377,8 +1387,8 @@ static struct socket *make_receive_sock(struct net *net)
> 
>  	return sock;
> 
> -  error:
> -	sock_release(sock);
> +error:
> +	sk_release_kernel(sock->sk);
>  	return ERR_PTR(result);
>  }
> 
> @@ -1473,7 +1483,7 @@ static int sync_thread_master(void *data)
>  		ip_vs_sync_buff_release(sb);
> 
>  	/* release the sending multicast socket */
> -	sock_release(tinfo->sock);
> +	sk_release_kernel(tinfo->sock->sk);
>  	kfree(tinfo);
> 
>  	return 0;
> @@ -1513,7 +1523,7 @@ static int sync_thread_backup(void *data)
>  	}
> 
>  	/* release the sending multicast socket */
> -	sock_release(tinfo->sock);
> +	sk_release_kernel(tinfo->sock->sk);
>  	kfree(tinfo->buf);
>  	kfree(tinfo);
> 
> @@ -1601,7 +1611,7 @@ outtinfo:
>  outbuf:
>  	kfree(buf);
>  outsocket:
> -	sock_release(sock);
> +	sk_release_kernel(sock->sk);
>  out:
>  	return result;
>  }
> --
> 1.7.2.3
> 
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