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Commit ae1d48b2 authored by Hans Schillstrom's avatar Hans Schillstrom Committed by Pablo Neira Ayuso
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IPVS netns shutdown/startup dead-lock 



ip_vs_mutext is used by both netns shutdown code and startup
and both implicit uses sk_lock-AF_INET mutex.

cleanup CPU-1         startup CPU-2
ip_vs_dst_event()     ip_vs_genl_set_cmd()
 sk_lock-AF_INET     __ip_vs_mutex
                     sk_lock-AF_INET
__ip_vs_mutex
* DEAD LOCK *

A new mutex placed in ip_vs netns struct called sync_mutex is added.

Comments from Julian and Simon added.
This patch has been running for more than 3 month now and it seems to work.

Ver. 3
    IP_VS_SO_GET_DAEMON in do_ip_vs_get_ctl protected by sync_mutex
    instead of __ip_vs_mutex as sugested by Julian.

Signed-off-by: default avatarHans Schillstrom <hans@schillstrom.com>
Acked-by: default avatarJulian Anastasov <ja@ssi.bg>
Signed-off-by: default avatarSimon Horman <horms@verge.net.au>
Signed-off-by: default avatarPablo Neira Ayuso <pablo@netfilter.org>
parent 98d9ae84

include/net/ip_vs.h

+1 −0
Original line number Diff line number Diff line
@@ -900,6 +900,7 @@ struct netns_ipvs { 
	volatile int		sync_state;

	volatile int		master_syncid;

	volatile int		backup_syncid;

	struct mutex		sync_mutex;

	/* multicast interface name */

	char			master_mcast_ifn[IP_VS_IFNAME_MAXLEN];

	char			backup_mcast_ifn[IP_VS_IFNAME_MAXLEN];

net/netfilter/ipvs/ip_vs_ctl.c

+80 −51
Original line number Diff line number Diff line
@@ -2283,6 +2283,7 @@ do_ip_vs_set_ctl(struct sock *sk, int cmd, void __user *user, unsigned int len) 
	struct ip_vs_service *svc;

	struct ip_vs_dest_user *udest_compat;

	struct ip_vs_dest_user_kern udest;

	struct netns_ipvs *ipvs = net_ipvs(net);



	if (!capable(CAP_NET_ADMIN))

		return -EPERM;
@@ -2303,6 +2304,24 @@ do_ip_vs_set_ctl(struct sock *sk, int cmd, void __user *user, unsigned int len) 
	/* increase the module use count */

	ip_vs_use_count_inc();



	/* Handle daemons since they have another lock */

	if (cmd == IP_VS_SO_SET_STARTDAEMON ||

	    cmd == IP_VS_SO_SET_STOPDAEMON) {

		struct ip_vs_daemon_user *dm = (struct ip_vs_daemon_user *)arg;



		if (mutex_lock_interruptible(&ipvs->sync_mutex)) {

			ret = -ERESTARTSYS;

			goto out_dec;

		}

		if (cmd == IP_VS_SO_SET_STARTDAEMON)

			ret = start_sync_thread(net, dm->state, dm->mcast_ifn,

						dm->syncid);

		else

			ret = stop_sync_thread(net, dm->state);

		mutex_unlock(&ipvs->sync_mutex);

		goto out_dec;

	}



	if (mutex_lock_interruptible(&__ip_vs_mutex)) {

		ret = -ERESTARTSYS;

		goto out_dec;
@@ -2316,15 +2335,6 @@ do_ip_vs_set_ctl(struct sock *sk, int cmd, void __user *user, unsigned int len) 
		/* Set timeout values for (tcp tcpfin udp) */

		ret = ip_vs_set_timeout(net, (struct ip_vs_timeout_user *)arg);

		goto out_unlock;

	} else if (cmd == IP_VS_SO_SET_STARTDAEMON) {

		struct ip_vs_daemon_user *dm = (struct ip_vs_daemon_user *)arg;

		ret = start_sync_thread(net, dm->state, dm->mcast_ifn,

					dm->syncid);

		goto out_unlock;

	} else if (cmd == IP_VS_SO_SET_STOPDAEMON) {

		struct ip_vs_daemon_user *dm = (struct ip_vs_daemon_user *)arg;

		ret = stop_sync_thread(net, dm->state);

		goto out_unlock;

	}



	usvc_compat = (struct ip_vs_service_user *)arg;
@@ -2584,6 +2594,33 @@ do_ip_vs_get_ctl(struct sock *sk, int cmd, void __user *user, int *len) 


	if (copy_from_user(arg, user, copylen) != 0)

		return -EFAULT;

	/*

	 * Handle daemons first since it has its own locking

	 */

	if (cmd == IP_VS_SO_GET_DAEMON) {

		struct ip_vs_daemon_user d[2];



		memset(&d, 0, sizeof(d));

		if (mutex_lock_interruptible(&ipvs->sync_mutex))

			return -ERESTARTSYS;



		if (ipvs->sync_state & IP_VS_STATE_MASTER) {

			d[0].state = IP_VS_STATE_MASTER;

			strlcpy(d[0].mcast_ifn, ipvs->master_mcast_ifn,

				sizeof(d[0].mcast_ifn));

			d[0].syncid = ipvs->master_syncid;

		}

		if (ipvs->sync_state & IP_VS_STATE_BACKUP) {

			d[1].state = IP_VS_STATE_BACKUP;

			strlcpy(d[1].mcast_ifn, ipvs->backup_mcast_ifn,

				sizeof(d[1].mcast_ifn));

			d[1].syncid = ipvs->backup_syncid;

		}

		if (copy_to_user(user, &d, sizeof(d)) != 0)

			ret = -EFAULT;

		mutex_unlock(&ipvs->sync_mutex);

		return ret;

	}



	if (mutex_lock_interruptible(&__ip_vs_mutex))

		return -ERESTARTSYS;
@@ -2681,28 +2718,6 @@ do_ip_vs_get_ctl(struct sock *sk, int cmd, void __user *user, int *len) 
	}

	break;



	case IP_VS_SO_GET_DAEMON:

	{

		struct ip_vs_daemon_user d[2];



		memset(&d, 0, sizeof(d));

		if (ipvs->sync_state & IP_VS_STATE_MASTER) {

			d[0].state = IP_VS_STATE_MASTER;

			strlcpy(d[0].mcast_ifn, ipvs->master_mcast_ifn,

				sizeof(d[0].mcast_ifn));

			d[0].syncid = ipvs->master_syncid;

		}

		if (ipvs->sync_state & IP_VS_STATE_BACKUP) {

			d[1].state = IP_VS_STATE_BACKUP;

			strlcpy(d[1].mcast_ifn, ipvs->backup_mcast_ifn,

				sizeof(d[1].mcast_ifn));

			d[1].syncid = ipvs->backup_syncid;

		}

		if (copy_to_user(user, &d, sizeof(d)) != 0)

			ret = -EFAULT;

	}

	break;



	default:

		ret = -EINVAL;

	}
@@ -3205,7 +3220,7 @@ static int ip_vs_genl_dump_daemons(struct sk_buff *skb, 
	struct net *net = skb_sknet(skb);

	struct netns_ipvs *ipvs = net_ipvs(net);



	mutex_lock(&__ip_vs_mutex);

	mutex_lock(&ipvs->sync_mutex);

	if ((ipvs->sync_state & IP_VS_STATE_MASTER) && !cb->args[0]) {

		if (ip_vs_genl_dump_daemon(skb, IP_VS_STATE_MASTER,

					   ipvs->master_mcast_ifn,
@@ -3225,7 +3240,7 @@ static int ip_vs_genl_dump_daemons(struct sk_buff *skb, 
	}



nla_put_failure:

	mutex_unlock(&__ip_vs_mutex);

	mutex_unlock(&ipvs->sync_mutex);



	return skb->len;

}
@@ -3271,13 +3286,9 @@ static int ip_vs_genl_set_config(struct net *net, struct nlattr **attrs) 
	return ip_vs_set_timeout(net, &t);

}



static int ip_vs_genl_set_cmd(struct sk_buff *skb, struct genl_info *info)

static int ip_vs_genl_set_daemon(struct sk_buff *skb, struct genl_info *info)

{

	struct ip_vs_service *svc = NULL;

	struct ip_vs_service_user_kern usvc;

	struct ip_vs_dest_user_kern udest;

	int ret = 0, cmd;

	int need_full_svc = 0, need_full_dest = 0;

	struct net *net;

	struct netns_ipvs *ipvs;
@@ -3285,19 +3296,10 @@ static int ip_vs_genl_set_cmd(struct sk_buff *skb, struct genl_info *info) 
	ipvs = net_ipvs(net);

	cmd = info->genlhdr->cmd;



	mutex_lock(&__ip_vs_mutex);



	if (cmd == IPVS_CMD_FLUSH) {

		ret = ip_vs_flush(net);

		goto out;

	} else if (cmd == IPVS_CMD_SET_CONFIG) {

		ret = ip_vs_genl_set_config(net, info->attrs);

		goto out;

	} else if (cmd == IPVS_CMD_NEW_DAEMON ||

		   cmd == IPVS_CMD_DEL_DAEMON) {



	if (cmd == IPVS_CMD_NEW_DAEMON || cmd == IPVS_CMD_DEL_DAEMON) {

		struct nlattr *daemon_attrs[IPVS_DAEMON_ATTR_MAX + 1];



		mutex_lock(&ipvs->sync_mutex);

		if (!info->attrs[IPVS_CMD_ATTR_DAEMON] ||

		    nla_parse_nested(daemon_attrs, IPVS_DAEMON_ATTR_MAX,

				     info->attrs[IPVS_CMD_ATTR_DAEMON],
@@ -3310,6 +3312,33 @@ static int ip_vs_genl_set_cmd(struct sk_buff *skb, struct genl_info *info) 
			ret = ip_vs_genl_new_daemon(net, daemon_attrs);

		else

			ret = ip_vs_genl_del_daemon(net, daemon_attrs);

out:

		mutex_unlock(&ipvs->sync_mutex);

	}

	return ret;

}



static int ip_vs_genl_set_cmd(struct sk_buff *skb, struct genl_info *info)

{

	struct ip_vs_service *svc = NULL;

	struct ip_vs_service_user_kern usvc;

	struct ip_vs_dest_user_kern udest;

	int ret = 0, cmd;

	int need_full_svc = 0, need_full_dest = 0;

	struct net *net;

	struct netns_ipvs *ipvs;



	net = skb_sknet(skb);

	ipvs = net_ipvs(net);

	cmd = info->genlhdr->cmd;



	mutex_lock(&__ip_vs_mutex);



	if (cmd == IPVS_CMD_FLUSH) {

		ret = ip_vs_flush(net);

		goto out;

	} else if (cmd == IPVS_CMD_SET_CONFIG) {

		ret = ip_vs_genl_set_config(net, info->attrs);

		goto out;

	} else if (cmd == IPVS_CMD_ZERO &&

		   !info->attrs[IPVS_CMD_ATTR_SERVICE]) {
@@ -3536,13 +3565,13 @@ static struct genl_ops ip_vs_genl_ops[] __read_mostly = { 
		.cmd	= IPVS_CMD_NEW_DAEMON,

		.flags	= GENL_ADMIN_PERM,

		.policy	= ip_vs_cmd_policy,

		.doit	= ip_vs_genl_set_cmd,

		.doit	= ip_vs_genl_set_daemon,

	},

	{

		.cmd	= IPVS_CMD_DEL_DAEMON,

		.flags	= GENL_ADMIN_PERM,

		.policy	= ip_vs_cmd_policy,

		.doit	= ip_vs_genl_set_cmd,

		.doit	= ip_vs_genl_set_daemon,

	},

	{

		.cmd	= IPVS_CMD_GET_DAEMON,

net/netfilter/ipvs/ip_vs_sync.c

+6 −0
Original line number Diff line number Diff line
@@ -61,6 +61,7 @@ 


#define SYNC_PROTO_VER  1		/* Protocol version in header */



static struct lock_class_key __ipvs_sync_key;

/*

 *	IPVS sync connection entry

 *	Version 0, i.e. original version.
@@ -1545,6 +1546,7 @@ int start_sync_thread(struct net *net, int state, char *mcast_ifn, __u8 syncid) 
	IP_VS_DBG(7, "Each ip_vs_sync_conn entry needs %Zd bytes\n",

		  sizeof(struct ip_vs_sync_conn_v0));





	if (state == IP_VS_STATE_MASTER) {

		if (ipvs->master_thread)

			return -EEXIST;
@@ -1667,6 +1669,7 @@ int __net_init ip_vs_sync_net_init(struct net *net) 
{

	struct netns_ipvs *ipvs = net_ipvs(net);



	__mutex_init(&ipvs->sync_mutex, "ipvs->sync_mutex", &__ipvs_sync_key);

	INIT_LIST_HEAD(&ipvs->sync_queue);

	spin_lock_init(&ipvs->sync_lock);

	spin_lock_init(&ipvs->sync_buff_lock);
@@ -1680,7 +1683,9 @@ int __net_init ip_vs_sync_net_init(struct net *net) 
void ip_vs_sync_net_cleanup(struct net *net)

{

	int retc;

	struct netns_ipvs *ipvs = net_ipvs(net);



	mutex_lock(&ipvs->sync_mutex);

	retc = stop_sync_thread(net, IP_VS_STATE_MASTER);

	if (retc && retc != -ESRCH)

		pr_err("Failed to stop Master Daemon\n");
@@ -1688,4 +1693,5 @@ void ip_vs_sync_net_cleanup(struct net *net) 
	retc = stop_sync_thread(net, IP_VS_STATE_BACKUP);

	if (retc && retc != -ESRCH)

		pr_err("Failed to stop Backup Daemon\n");

	mutex_unlock(&ipvs->sync_mutex);

}