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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: Hans Schillstrom <hans@schillstrom.com>
Acked-by: Julian Anastasov <ja@ssi.bg>
Signed-off-by: Simon Horman <horms@verge.net.au>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
This commit is contained in:
Hans Schillstrom 2011-10-11 10:54:35 +09:00 committed by Pablo Neira Ayuso
parent 98d9ae841a
commit ae1d48b23d
3 changed files with 89 additions and 53 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

1
include/net/ip_vs.h
View File

@ -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];

135
net/netfilter/ipvs/ip_vs_ctl.c
View File

@ -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;
}
@ -3271,6 +3286,38 @@ 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_daemon(struct sk_buff *skb, struct genl_info *info)
{
int ret = 0, cmd;
struct net *net;
struct netns_ipvs *ipvs;
net = skb_sknet(skb);
ipvs = net_ipvs(net);
cmd = info->genlhdr->cmd;
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],
ip_vs_daemon_policy)) {
ret = -EINVAL;
goto out;
}
if (cmd == IPVS_CMD_NEW_DAEMON)
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;
@ -3293,24 +3340,6 @@ static int ip_vs_genl_set_cmd(struct sk_buff *skb, struct genl_info *info)
} 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) {
struct nlattr *daemon_attrs[IPVS_DAEMON_ATTR_MAX + 1];
if (!info->attrs[IPVS_CMD_ATTR_DAEMON] ||
nla_parse_nested(daemon_attrs, IPVS_DAEMON_ATTR_MAX,
info->attrs[IPVS_CMD_ATTR_DAEMON],
ip_vs_daemon_policy)) {
ret = -EINVAL;
goto out;
}
if (cmd == IPVS_CMD_NEW_DAEMON)
ret = ip_vs_genl_new_daemon(net, daemon_attrs);
else
ret = ip_vs_genl_del_daemon(net, daemon_attrs);
goto out;
} else if (cmd == IPVS_CMD_ZERO &&
!info->attrs[IPVS_CMD_ATTR_SERVICE]) {
ret = ip_vs_zero_all(net);
@ -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,

6
net/netfilter/ipvs/ip_vs_sync.c
View File

@ -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);
}