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Date: Tue, 4 Oct 2011 10:40:29 +0300 (EEST)
From: Julian Anastasov <ja@....bg>
To: Hans Schillstrom <hans.schillstrom@...csson.com>
cc: horms@...ge.net.au, wensong@...ux-vs.org,
lvs-devel@...r.kernel.org, netdev@...r.kernel.org,
netfilter-devel@...r.kernel.org, hans@...illstrom.com
Subject: Re: [PATCH 2/2] IPVS netns shutdown/startup dead-lock (Take III)
Hello,
On Tue, 4 Oct 2011, Hans Schillstrom wrote:
> 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.
>
> 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@...illstrom.com>
Looks good to me, with one extra empty line in
start_sync_thread
Acked-by: Julian Anastasov <ja@....bg>
> ---
> include/net/ip_vs.h | 1 +
> net/netfilter/ipvs/ip_vs_ctl.c | 131 ++++++++++++++++++++++++---------------
> net/netfilter/ipvs/ip_vs_sync.c | 6 ++
> 3 files changed, 87 insertions(+), 51 deletions(-)
>
> 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..c77b5a0 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;
> @@ -2585,6 +2595,33 @@ 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;
> @@ -2682,28 +2719,6 @@ 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;
> }
> @@ -3206,7 +3221,7 @@ 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 +3241,7 @@ 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 +3287,9 @@ 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 +3297,10 @@ 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 +3313,33 @@ 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 +3566,13 @@ 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
Regards
--
Julian Anastasov <ja@....bg>
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