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Date: Mon, 3 Oct 2011 12:56:39 +0200
From: Hans Schillstrom <hans.schillstrom@...csson.com>
To: <horms@...ge.net.au>, <ja@....bg>, <wensong@...ux-vs.org>,
<lvs-devel@...r.kernel.org>, <netdev@...r.kernel.org>,
<netfilter-devel@...r.kernel.org>
CC: <hans@...illstrom.com>,
Hans Schillstrom <hans.schillstrom@...csson.com>
Subject: [PATCH 2/2] IPVS netns shutdown/startup dead-lock (Take II)
From: Hans Schillstrom <hans@...illstrom.com>
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.
Signed-off-by: Hans Schillstrom <hans.schillstrom@...csson.com>
diff --git a/include/net/ip_vs.h b/include/net/ip_vs.h
index 1aaf915..8fa4430 100644
--- a/include/net/ip_vs.h
+++ b/include/net/ip_vs.h
@@ -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];
diff --git a/net/netfilter/ipvs/ip_vs_ctl.c b/net/netfilter/ipvs/ip_vs_ctl.c
index a1af72f..cb5c25c 100644
--- a/net/netfilter/ipvs/ip_vs_ctl.c
+++ b/net/netfilter/ipvs/ip_vs_ctl.c
@@ -2284,6 +2284,7 @@ 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;
@@ -2304,6 +2305,24 @@ 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;
@@ -2317,15 +2336,6 @@ 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;
@@ -3206,7 +3216,7 @@ 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,
@@ -3226,7 +3236,7 @@ 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;
}
@@ -3272,13 +3282,9 @@ 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;
@@ -3286,19 +3292,10 @@ 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],
@@ -3311,6 +3308,33 @@ 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]) {
@@ -3537,13 +3561,13 @@ 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,
diff --git a/net/netfilter/ipvs/ip_vs_sync.c b/net/netfilter/ipvs/ip_vs_sync.c
index 7ee7215..3cdd479 100644
--- a/net/netfilter/ipvs/ip_vs_sync.c
+++ b/net/netfilter/ipvs/ip_vs_sync.c
@@ -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);
}
--
1.7.4.4
--
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