[PATCH 4.4 31/56] ipvs: fix rtnl_lock lockups caused by start_sync_thread

4.4-stable review patch. If anyone has any objections, please let me know.

------------------

From: Julian Anastasov ja@ssi.bg

commit 5c64576a77894a50be80be0024bed27171b55989 upstream.

syzkaller reports for wrong rtnl_lock usage in sync code [1] and [2]

We have 2 problems in start_sync_thread if error path is taken, eg. on memory allocation error or failure to configure sockets for mcast group or addr/port binding:

1. recursive locking: holding rtnl_lock while calling sock_release which in turn calls again rtnl_lock in ip_mc_drop_socket to leave the mcast group, as noticed by Florian Westphal. Additionally, sock_release can not be called while holding sync_mutex (ABBA deadlock).

2. task hung: holding rtnl_lock while calling kthread_stop to stop the running kthreads. As the kthreads do the same to leave the mcast group (sock_release -> ip_mc_drop_socket -> rtnl_lock) they hang.

Fix the problems by calling rtnl_unlock early in the error path, now sock_release is called after unlocking both mutexes.

Problem 3 (task hung reported by syzkaller [2]) is variant of problem 2: use _trylock to prevent one user to call rtnl_lock and then while waiting for sync_mutex to block kthreads that execute sock_release when they are stopped by stop_sync_thread.

[1] IPVS: stopping backup sync thread 4500 ... WARNING: possible recursive locking detected 4.16.0-rc7+ #3 Not tainted -------------------------------------------- syzkaller688027/4497 is trying to acquire lock: (rtnl_mutex){+.+.}, at: [<00000000bb14d7fb>] rtnl_lock+0x17/0x20 net/core/rtnetlink.c:74

but task is already holding lock: IPVS: stopping backup sync thread 4495 ... (rtnl_mutex){+.+.}, at: [<00000000bb14d7fb>] rtnl_lock+0x17/0x20 net/core/rtnetlink.c:74

other info that might help us debug this: Possible unsafe locking scenario:

CPU0 ---- lock(rtnl_mutex); lock(rtnl_mutex);

*** DEADLOCK ***

May be due to missing lock nesting notation

2 locks held by syzkaller688027/4497: #0: (rtnl_mutex){+.+.}, at: [<00000000bb14d7fb>] rtnl_lock+0x17/0x20 net/core/rtnetlink.c:74 #1: (ipvs->sync_mutex){+.+.}, at: [<00000000703f78e3>] do_ip_vs_set_ctl+0x10f8/0x1cc0 net/netfilter/ipvs/ip_vs_ctl.c:2388

stack backtrace: CPU: 1 PID: 4497 Comm: syzkaller688027 Not tainted 4.16.0-rc7+ #3 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 Call Trace: __dump_stack lib/dump_stack.c:17 [inline] dump_stack+0x194/0x24d lib/dump_stack.c:53 print_deadlock_bug kernel/locking/lockdep.c:1761 [inline] check_deadlock kernel/locking/lockdep.c:1805 [inline] validate_chain kernel/locking/lockdep.c:2401 [inline] __lock_acquire+0xe8f/0x3e00 kernel/locking/lockdep.c:3431 lock_acquire+0x1d5/0x580 kernel/locking/lockdep.c:3920 __mutex_lock_common kernel/locking/mutex.c:756 [inline] __mutex_lock+0x16f/0x1a80 kernel/locking/mutex.c:893 mutex_lock_nested+0x16/0x20 kernel/locking/mutex.c:908 rtnl_lock+0x17/0x20 net/core/rtnetlink.c:74 ip_mc_drop_socket+0x88/0x230 net/ipv4/igmp.c:2643 inet_release+0x4e/0x1c0 net/ipv4/af_inet.c:413 sock_release+0x8d/0x1e0 net/socket.c:595 start_sync_thread+0x2213/0x2b70 net/netfilter/ipvs/ip_vs_sync.c:1924 do_ip_vs_set_ctl+0x1139/0x1cc0 net/netfilter/ipvs/ip_vs_ctl.c:2389 nf_sockopt net/netfilter/nf_sockopt.c:106 [inline] nf_setsockopt+0x67/0xc0 net/netfilter/nf_sockopt.c:115 ip_setsockopt+0x97/0xa0 net/ipv4/ip_sockglue.c:1261 udp_setsockopt+0x45/0x80 net/ipv4/udp.c:2406 sock_common_setsockopt+0x95/0xd0 net/core/sock.c:2975 SYSC_setsockopt net/socket.c:1849 [inline] SyS_setsockopt+0x189/0x360 net/socket.c:1828 do_syscall_64+0x281/0x940 arch/x86/entry/common.c:287 entry_SYSCALL_64_after_hwframe+0x42/0xb7 RIP: 0033:0x446a69 RSP: 002b:00007fa1c3a64da8 EFLAGS: 00000246 ORIG_RAX: 0000000000000036 RAX: ffffffffffffffda RBX: 0000000000000000 RCX: 0000000000446a69 RDX: 000000000000048b RSI: 0000000000000000 RDI: 0000000000000003 RBP: 00000000006e29fc R08: 0000000000000018 R09: 0000000000000000 R10: 00000000200000c0 R11: 0000000000000246 R12: 00000000006e29f8 R13: 00676e697279656b R14: 00007fa1c3a659c0 R15: 00000000006e2b60

[2] IPVS: sync thread started: state = BACKUP, mcast_ifn = syz_tun, syncid = 4, id = 0 IPVS: stopping backup sync thread 25415 ... INFO: task syz-executor7:25421 blocked for more than 120 seconds. Not tainted 4.16.0-rc6+ #284 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. syz-executor7 D23688 25421 4408 0x00000004 Call Trace: context_switch kernel/sched/core.c:2862 [inline] __schedule+0x8fb/0x1ec0 kernel/sched/core.c:3440 schedule+0xf5/0x430 kernel/sched/core.c:3499 schedule_timeout+0x1a3/0x230 kernel/time/timer.c:1777 do_wait_for_common kernel/sched/completion.c:86 [inline] __wait_for_common kernel/sched/completion.c:107 [inline] wait_for_common kernel/sched/completion.c:118 [inline] wait_for_completion+0x415/0x770 kernel/sched/completion.c:139 kthread_stop+0x14a/0x7a0 kernel/kthread.c:530 stop_sync_thread+0x3d9/0x740 net/netfilter/ipvs/ip_vs_sync.c:1996 do_ip_vs_set_ctl+0x2b1/0x1cc0 net/netfilter/ipvs/ip_vs_ctl.c:2394 nf_sockopt net/netfilter/nf_sockopt.c:106 [inline] nf_setsockopt+0x67/0xc0 net/netfilter/nf_sockopt.c:115 ip_setsockopt+0x97/0xa0 net/ipv4/ip_sockglue.c:1253 sctp_setsockopt+0x2ca/0x63e0 net/sctp/socket.c:4154 sock_common_setsockopt+0x95/0xd0 net/core/sock.c:3039 SYSC_setsockopt net/socket.c:1850 [inline] SyS_setsockopt+0x189/0x360 net/socket.c:1829 do_syscall_64+0x281/0x940 arch/x86/entry/common.c:287 entry_SYSCALL_64_after_hwframe+0x42/0xb7 RIP: 0033:0x454889 RSP: 002b:00007fc927626c68 EFLAGS: 00000246 ORIG_RAX: 0000000000000036 RAX: ffffffffffffffda RBX: 00007fc9276276d4 RCX: 0000000000454889 RDX: 000000000000048c RSI: 0000000000000000 RDI: 0000000000000017 RBP: 000000000072bf58 R08: 0000000000000018 R09: 0000000000000000 R10: 0000000020000000 R11: 0000000000000246 R12: 00000000ffffffff R13: 000000000000051c R14: 00000000006f9b40 R15: 0000000000000001

Showing all locks held in the system: 2 locks held by khungtaskd/868: #0: (rcu_read_lock){....}, at: [<00000000a1a8f002>] check_hung_uninterruptible_tasks kernel/hung_task.c:175 [inline] #0: (rcu_read_lock){....}, at: [<00000000a1a8f002>] watchdog+0x1c5/0xd60 kernel/hung_task.c:249 #1: (tasklist_lock){.+.+}, at: [<0000000037c2f8f9>] debug_show_all_locks+0xd3/0x3d0 kernel/locking/lockdep.c:4470 1 lock held by rsyslogd/4247: #0: (&f->f_pos_lock){+.+.}, at: [<000000000d8d6983>] __fdget_pos+0x12b/0x190 fs/file.c:765 2 locks held by getty/4338: #0: (&tty->ldisc_sem){++++}, at: [<00000000bee98654>] ldsem_down_read+0x37/0x40 drivers/tty/tty_ldsem.c:365 #1: (&ldata->atomic_read_lock){+.+.}, at: [<00000000c1d180aa>] n_tty_read+0x2ef/0x1a40 drivers/tty/n_tty.c:2131 2 locks held by getty/4339: #0: (&tty->ldisc_sem){++++}, at: [<00000000bee98654>] ldsem_down_read+0x37/0x40 drivers/tty/tty_ldsem.c:365 #1: (&ldata->atomic_read_lock){+.+.}, at: [<00000000c1d180aa>] n_tty_read+0x2ef/0x1a40 drivers/tty/n_tty.c:2131 2 locks held by getty/4340: #0: (&tty->ldisc_sem){++++}, at: [<00000000bee98654>] ldsem_down_read+0x37/0x40 drivers/tty/tty_ldsem.c:365 #1: (&ldata->atomic_read_lock){+.+.}, at: [<00000000c1d180aa>] n_tty_read+0x2ef/0x1a40 drivers/tty/n_tty.c:2131 2 locks held by getty/4341: #0: (&tty->ldisc_sem){++++}, at: [<00000000bee98654>] ldsem_down_read+0x37/0x40 drivers/tty/tty_ldsem.c:365 #1: (&ldata->atomic_read_lock){+.+.}, at: [<00000000c1d180aa>] n_tty_read+0x2ef/0x1a40 drivers/tty/n_tty.c:2131 2 locks held by getty/4342: #0: (&tty->ldisc_sem){++++}, at: [<00000000bee98654>] ldsem_down_read+0x37/0x40 drivers/tty/tty_ldsem.c:365 #1: (&ldata->atomic_read_lock){+.+.}, at: [<00000000c1d180aa>] n_tty_read+0x2ef/0x1a40 drivers/tty/n_tty.c:2131 2 locks held by getty/4343: #0: (&tty->ldisc_sem){++++}, at: [<00000000bee98654>] ldsem_down_read+0x37/0x40 drivers/tty/tty_ldsem.c:365 #1: (&ldata->atomic_read_lock){+.+.}, at: [<00000000c1d180aa>] n_tty_read+0x2ef/0x1a40 drivers/tty/n_tty.c:2131 2 locks held by getty/4344: #0: (&tty->ldisc_sem){++++}, at: [<00000000bee98654>] ldsem_down_read+0x37/0x40 drivers/tty/tty_ldsem.c:365 #1: (&ldata->atomic_read_lock){+.+.}, at: [<00000000c1d180aa>] n_tty_read+0x2ef/0x1a40 drivers/tty/n_tty.c:2131 3 locks held by kworker/0:5/6494: #0: ((wq_completion)"%s"("ipv6_addrconf")){+.+.}, at: [<00000000a062b18e>] work_static include/linux/workqueue.h:198 [inline] #0: ((wq_completion)"%s"("ipv6_addrconf")){+.+.}, at: [<00000000a062b18e>] set_work_data kernel/workqueue.c:619 [inline] #0: ((wq_completion)"%s"("ipv6_addrconf")){+.+.}, at: [<00000000a062b18e>] set_work_pool_and_clear_pending kernel/workqueue.c:646 [inline] #0: ((wq_completion)"%s"("ipv6_addrconf")){+.+.}, at: [<00000000a062b18e>] process_one_work+0xb12/0x1bb0 kernel/workqueue.c:2084 #1: ((addr_chk_work).work){+.+.}, at: [<00000000278427d5>] process_one_work+0xb89/0x1bb0 kernel/workqueue.c:2088 #2: (rtnl_mutex){+.+.}, at: [<00000000066e35ac>] rtnl_lock+0x17/0x20 net/core/rtnetlink.c:74 1 lock held by syz-executor7/25421: #0: (ipvs->sync_mutex){+.+.}, at: [<00000000d414a689>] do_ip_vs_set_ctl+0x277/0x1cc0 net/netfilter/ipvs/ip_vs_ctl.c:2393 2 locks held by syz-executor7/25427: #0: (rtnl_mutex){+.+.}, at: [<00000000066e35ac>] rtnl_lock+0x17/0x20 net/core/rtnetlink.c:74 #1: (ipvs->sync_mutex){+.+.}, at: [<00000000e6d48489>] do_ip_vs_set_ctl+0x10f8/0x1cc0 net/netfilter/ipvs/ip_vs_ctl.c:2388 1 lock held by syz-executor7/25435: #0: (rtnl_mutex){+.+.}, at: [<00000000066e35ac>] rtnl_lock+0x17/0x20 net/core/rtnetlink.c:74 1 lock held by ipvs-b:2:0/25415: #0: (rtnl_mutex){+.+.}, at: [<00000000066e35ac>] rtnl_lock+0x17/0x20 net/core/rtnetlink.c:74

Reported-and-tested-by: syzbot+a46d6abf9d56b1365a72@syzkaller.appspotmail.com Reported-and-tested-by: syzbot+5fe074c01b2032ce9618@syzkaller.appspotmail.com Fixes: e0b26cc997d5 ("ipvs: call rtnl_lock early") Signed-off-by: Julian Anastasov ja@ssi.bg Signed-off-by: Simon Horman horms@verge.net.au Signed-off-by: Pablo Neira Ayuso pablo@netfilter.org Cc: Zubin Mithra zsm@chromium.org Cc: Guenter Roeck groeck@chromium.org Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org

--- net/netfilter/ipvs/ip_vs_ctl.c | 8 -- net/netfilter/ipvs/ip_vs_sync.c | 155 ++++++++++++++++++++-------------------- 2 files changed, 80 insertions(+), 83 deletions(-)

--- a/net/netfilter/ipvs/ip_vs_ctl.c +++ b/net/netfilter/ipvs/ip_vs_ctl.c @@ -2352,11 +2352,7 @@ do_ip_vs_set_ctl(struct sock *sk, int cm strlcpy(cfg.mcast_ifn, dm->mcast_ifn, sizeof(cfg.mcast_ifn)); cfg.syncid = dm->syncid; - rtnl_lock(); - mutex_lock(&ipvs->sync_mutex); ret = start_sync_thread(ipvs, &cfg, dm->state); - mutex_unlock(&ipvs->sync_mutex); - rtnl_unlock(); } else { mutex_lock(&ipvs->sync_mutex); ret = stop_sync_thread(ipvs, dm->state); @@ -3435,12 +3431,8 @@ static int ip_vs_genl_new_daemon(struct if (ipvs->mixed_address_family_dests > 0) return -EINVAL;

- rtnl_lock(); - mutex_lock(&ipvs->sync_mutex); ret = start_sync_thread(ipvs, &c, nla_get_u32(attrs[IPVS_DAEMON_ATTR_STATE])); - mutex_unlock(&ipvs->sync_mutex); - rtnl_unlock(); return ret; }

--- a/net/netfilter/ipvs/ip_vs_sync.c +++ b/net/netfilter/ipvs/ip_vs_sync.c @@ -48,6 +48,7 @@ #include <linux/kthread.h> #include <linux/wait.h> #include <linux/kernel.h> +#include <linux/sched.h>

#include <asm/unaligned.h> /* Used for ntoh_seq and hton_seq */

@@ -1356,15 +1357,9 @@ static void set_mcast_pmtudisc(struct so /* * Specifiy default interface for outgoing multicasts */ -static int set_mcast_if(struct sock *sk, char *ifname) +static int set_mcast_if(struct sock *sk, struct net_device *dev) { - struct net_device *dev; struct inet_sock *inet = inet_sk(sk); - struct net *net = sock_net(sk); - - dev = __dev_get_by_name(net, ifname); - if (!dev) - return -ENODEV;

if (sk->sk_bound_dev_if && dev->ifindex != sk->sk_bound_dev_if) return -EINVAL; @@ -1392,19 +1387,14 @@ static int set_mcast_if(struct sock *sk, * in the in_addr structure passed in as a parameter. */ static int -join_mcast_group(struct sock *sk, struct in_addr *addr, char *ifname) +join_mcast_group(struct sock *sk, struct in_addr *addr, struct net_device *dev) { - struct net *net = sock_net(sk); struct ip_mreqn mreq; - struct net_device *dev; int ret;

memset(&mreq, 0, sizeof(mreq)); memcpy(&mreq.imr_multiaddr, addr, sizeof(struct in_addr));

- dev = __dev_get_by_name(net, ifname); - if (!dev) - return -ENODEV; if (sk->sk_bound_dev_if && dev->ifindex != sk->sk_bound_dev_if) return -EINVAL;

@@ -1419,15 +1409,10 @@ join_mcast_group(struct sock *sk, struct

#ifdef CONFIG_IP_VS_IPV6 static int join_mcast_group6(struct sock *sk, struct in6_addr *addr, - char *ifname) + struct net_device *dev) { - struct net *net = sock_net(sk); - struct net_device *dev; int ret;

- dev = __dev_get_by_name(net, ifname); - if (!dev) - return -ENODEV; if (sk->sk_bound_dev_if && dev->ifindex != sk->sk_bound_dev_if) return -EINVAL;

@@ -1439,24 +1424,18 @@ static int join_mcast_group6(struct sock } #endif

-static int bind_mcastif_addr(struct socket *sock, char *ifname) +static int bind_mcastif_addr(struct socket *sock, struct net_device *dev) { - struct net *net = sock_net(sock->sk); - struct net_device *dev; __be32 addr; struct sockaddr_in sin;

- dev = __dev_get_by_name(net, ifname); - if (!dev) - return -ENODEV; - addr = inet_select_addr(dev, 0, RT_SCOPE_UNIVERSE); if (!addr) pr_err("You probably need to specify IP address on " "multicast interface.\n");

IP_VS_DBG(7, "binding socket with (%s) %pI4\n", - ifname, &addr); + dev->name, &addr);

/* Now bind the socket with the address of multicast interface */ sin.sin_family = AF_INET; @@ -1489,7 +1468,8 @@ static void get_mcast_sockaddr(union ipv /* * Set up sending multicast socket over UDP */ -static struct socket *make_send_sock(struct netns_ipvs *ipvs, int id) +static int make_send_sock(struct netns_ipvs *ipvs, int id, + struct net_device *dev, struct socket **sock_ret) { /* multicast addr */ union ipvs_sockaddr mcast_addr; @@ -1501,9 +1481,10 @@ static struct socket *make_send_sock(str IPPROTO_UDP, &sock); if (result < 0) { pr_err("Error during creation of socket; terminating\n"); - return ERR_PTR(result); + goto error; } - result = set_mcast_if(sock->sk, ipvs->mcfg.mcast_ifn); + *sock_ret = sock; + result = set_mcast_if(sock->sk, dev); if (result < 0) { pr_err("Error setting outbound mcast interface\n"); goto error; @@ -1518,7 +1499,7 @@ static struct socket *make_send_sock(str set_sock_size(sock->sk, 1, result);

if (AF_INET == ipvs->mcfg.mcast_af) - result = bind_mcastif_addr(sock, ipvs->mcfg.mcast_ifn); + result = bind_mcastif_addr(sock, dev); else result = 0; if (result < 0) { @@ -1534,19 +1515,18 @@ static struct socket *make_send_sock(str goto error; }

- return sock; + return 0;

error: - sock_release(sock); - return ERR_PTR(result); + return result; }

/* * Set up receiving multicast socket over UDP */ -static struct socket *make_receive_sock(struct netns_ipvs *ipvs, int id, - int ifindex) +static int make_receive_sock(struct netns_ipvs *ipvs, int id, + struct net_device *dev, struct socket **sock_ret) { /* multicast addr */ union ipvs_sockaddr mcast_addr; @@ -1558,8 +1538,9 @@ static struct socket *make_receive_sock( IPPROTO_UDP, &sock); if (result < 0) { pr_err("Error during creation of socket; terminating\n"); - return ERR_PTR(result); + goto error; } + *sock_ret = sock; /* it is equivalent to the REUSEADDR option in user-space */ sock->sk->sk_reuse = SK_CAN_REUSE; result = sysctl_sync_sock_size(ipvs); @@ -1567,7 +1548,7 @@ static struct socket *make_receive_sock( set_sock_size(sock->sk, 0, result);

get_mcast_sockaddr(&mcast_addr, &salen, &ipvs->bcfg, id); - sock->sk->sk_bound_dev_if = ifindex; + sock->sk->sk_bound_dev_if = dev->ifindex; result = sock->ops->bind(sock, (struct sockaddr *)&mcast_addr, salen); if (result < 0) { pr_err("Error binding to the multicast addr\n"); @@ -1578,21 +1559,20 @@ static struct socket *make_receive_sock( #ifdef CONFIG_IP_VS_IPV6 if (ipvs->bcfg.mcast_af == AF_INET6) result = join_mcast_group6(sock->sk, &mcast_addr.in6.sin6_addr, - ipvs->bcfg.mcast_ifn); + dev); else #endif result = join_mcast_group(sock->sk, &mcast_addr.in.sin_addr, - ipvs->bcfg.mcast_ifn); + dev); if (result < 0) { pr_err("Error joining to the multicast group\n"); goto error; }

- return sock; + return 0;

error: - sock_release(sock); - return ERR_PTR(result); + return result; }

@@ -1777,13 +1757,12 @@ static int sync_thread_backup(void *data int start_sync_thread(struct netns_ipvs *ipvs, struct ipvs_sync_daemon_cfg *c, int state) { - struct ip_vs_sync_thread_data *tinfo; + struct ip_vs_sync_thread_data *tinfo = NULL; struct task_struct **array = NULL, *task; - struct socket *sock; struct net_device *dev; char *name; int (*threadfn)(void *data); - int id, count, hlen; + int id = 0, count, hlen; int result = -ENOMEM; u16 mtu, min_mtu;

@@ -1791,6 +1770,18 @@ int start_sync_thread(struct netns_ipvs IP_VS_DBG(7, "Each ip_vs_sync_conn entry needs %Zd bytes\n", sizeof(struct ip_vs_sync_conn_v0));

+ /* Do not hold one mutex and then to block on another */ + for (;;) { + rtnl_lock(); + if (mutex_trylock(&ipvs->sync_mutex)) + break; + rtnl_unlock(); + mutex_lock(&ipvs->sync_mutex); + if (rtnl_trylock()) + break; + mutex_unlock(&ipvs->sync_mutex); + } + if (!ipvs->sync_state) { count = clamp(sysctl_sync_ports(ipvs), 1, IPVS_SYNC_PORTS_MAX); ipvs->threads_mask = count - 1; @@ -1809,7 +1800,8 @@ int start_sync_thread(struct netns_ipvs dev = __dev_get_by_name(ipvs->net, c->mcast_ifn); if (!dev) { pr_err("Unknown mcast interface: %s\n", c->mcast_ifn); - return -ENODEV; + result = -ENODEV; + goto out_early; } hlen = (AF_INET6 == c->mcast_af) ? sizeof(struct ipv6hdr) + sizeof(struct udphdr) : @@ -1826,26 +1818,30 @@ int start_sync_thread(struct netns_ipvs c->sync_maxlen = mtu - hlen;

if (state == IP_VS_STATE_MASTER) { + result = -EEXIST; if (ipvs->ms) - return -EEXIST; + goto out_early;

ipvs->mcfg = *c; name = "ipvs-m:%d:%d"; threadfn = sync_thread_master; } else if (state == IP_VS_STATE_BACKUP) { + result = -EEXIST; if (ipvs->backup_threads) - return -EEXIST; + goto out_early;

ipvs->bcfg = *c; name = "ipvs-b:%d:%d"; threadfn = sync_thread_backup; } else { - return -EINVAL; + result = -EINVAL; + goto out_early; }

if (state == IP_VS_STATE_MASTER) { struct ipvs_master_sync_state *ms;

+ result = -ENOMEM; ipvs->ms = kzalloc(count * sizeof(ipvs->ms[0]), GFP_KERNEL); if (!ipvs->ms) goto out; @@ -1861,39 +1857,38 @@ int start_sync_thread(struct netns_ipvs } else { array = kzalloc(count * sizeof(struct task_struct *), GFP_KERNEL); + result = -ENOMEM; if (!array) goto out; }

- tinfo = NULL; for (id = 0; id < count; id++) { - if (state == IP_VS_STATE_MASTER) - sock = make_send_sock(ipvs, id); - else - sock = make_receive_sock(ipvs, id, dev->ifindex); - if (IS_ERR(sock)) { - result = PTR_ERR(sock); - goto outtinfo; - } + result = -ENOMEM; tinfo = kmalloc(sizeof(*tinfo), GFP_KERNEL); if (!tinfo) - goto outsocket; + goto out; tinfo->ipvs = ipvs; - tinfo->sock = sock; + tinfo->sock = NULL; if (state == IP_VS_STATE_BACKUP) { tinfo->buf = kmalloc(ipvs->bcfg.sync_maxlen, GFP_KERNEL); if (!tinfo->buf) - goto outtinfo; + goto out; } else { tinfo->buf = NULL; } tinfo->id = id; + if (state == IP_VS_STATE_MASTER) + result = make_send_sock(ipvs, id, dev, &tinfo->sock); + else + result = make_receive_sock(ipvs, id, dev, &tinfo->sock); + if (result < 0) + goto out;

task = kthread_run(threadfn, tinfo, name, ipvs->gen, id); if (IS_ERR(task)) { result = PTR_ERR(task); - goto outtinfo; + goto out; } tinfo = NULL; if (state == IP_VS_STATE_MASTER) @@ -1910,20 +1905,20 @@ int start_sync_thread(struct netns_ipvs ipvs->sync_state |= state; spin_unlock_bh(&ipvs->sync_buff_lock);

+ mutex_unlock(&ipvs->sync_mutex); + rtnl_unlock(); + /* increase the module use count */ ip_vs_use_count_inc();

return 0;

-outsocket: - sock_release(sock); - -outtinfo: - if (tinfo) { - sock_release(tinfo->sock); - kfree(tinfo->buf); - kfree(tinfo); - } +out: + /* We do not need RTNL lock anymore, release it here so that + * sock_release below and in the kthreads can use rtnl_lock + * to leave the mcast group. + */ + rtnl_unlock(); count = id; while (count-- > 0) { if (state == IP_VS_STATE_MASTER) @@ -1931,13 +1926,23 @@ outtinfo: else kthread_stop(array[count]); } - kfree(array); - -out: if (!(ipvs->sync_state & IP_VS_STATE_MASTER)) { kfree(ipvs->ms); ipvs->ms = NULL; } + mutex_unlock(&ipvs->sync_mutex); + if (tinfo) { + if (tinfo->sock) + sock_release(tinfo->sock); + kfree(tinfo->buf); + kfree(tinfo); + } + kfree(array); + return result; + +out_early: + mutex_unlock(&ipvs->sync_mutex); + rtnl_unlock(); return result; }