4.20-stable review patch. If anyone has any objections, please let me know.
------------------
[ Upstream commit 5a86d68bcf02f2d1e9a5897dd482079fd5f75e7f ]
When network namespace is destroyed, cleanup_net() is called. cleanup_net() holds pernet_ops_rwsem then calls each ->exit callback. So that clusterip_tg_destroy() is called by cleanup_net(). And clusterip_tg_destroy() calls unregister_netdevice_notifier().
But both cleanup_net() and clusterip_tg_destroy() hold same lock(pernet_ops_rwsem). hence deadlock occurrs.
After this patch, only 1 notifier is registered when module is inserted. And all of configs are added to per-net list.
test commands: %ip netns add vm1 %ip netns exec vm1 bash %ip link set lo up %iptables -A INPUT -p tcp -i lo -d 192.168.0.5 --dport 80 \ -j CLUSTERIP --new --hashmode sourceip \ --clustermac 01:00:5e:00:00:20 --total-nodes 2 --local-node 1 %exit %ip netns del vm1
splat looks like: [ 341.809674] ============================================ [ 341.809674] WARNING: possible recursive locking detected [ 341.809674] 4.19.0-rc5+ #16 Tainted: G W [ 341.809674] -------------------------------------------- [ 341.809674] kworker/u4:2/87 is trying to acquire lock: [ 341.809674] 000000005da2d519 (pernet_ops_rwsem){++++}, at: unregister_netdevice_notifier+0x8c/0x460 [ 341.809674] [ 341.809674] but task is already holding lock: [ 341.809674] 000000005da2d519 (pernet_ops_rwsem){++++}, at: cleanup_net+0x119/0x900 [ 341.809674] [ 341.809674] other info that might help us debug this: [ 341.809674] Possible unsafe locking scenario: [ 341.809674] [ 341.809674] CPU0 [ 341.809674] ---- [ 341.809674] lock(pernet_ops_rwsem); [ 341.809674] lock(pernet_ops_rwsem); [ 341.809674] [ 341.809674] *** DEADLOCK *** [ 341.809674] [ 341.809674] May be due to missing lock nesting notation [ 341.809674] [ 341.809674] 3 locks held by kworker/u4:2/87: [ 341.809674] #0: 00000000d9df6c92 ((wq_completion)"%s""netns"){+.+.}, at: process_one_work+0xafe/0x1de0 [ 341.809674] #1: 00000000c2cbcee2 (net_cleanup_work){+.+.}, at: process_one_work+0xb60/0x1de0 [ 341.809674] #2: 000000005da2d519 (pernet_ops_rwsem){++++}, at: cleanup_net+0x119/0x900 [ 341.809674] [ 341.809674] stack backtrace: [ 341.809674] CPU: 1 PID: 87 Comm: kworker/u4:2 Tainted: G W 4.19.0-rc5+ #16 [ 341.809674] Workqueue: netns cleanup_net [ 341.809674] Call Trace: [ ... ] [ 342.070196] down_write+0x93/0x160 [ 342.070196] ? unregister_netdevice_notifier+0x8c/0x460 [ 342.070196] ? down_read+0x1e0/0x1e0 [ 342.070196] ? sched_clock_cpu+0x126/0x170 [ 342.070196] ? find_held_lock+0x39/0x1c0 [ 342.070196] unregister_netdevice_notifier+0x8c/0x460 [ 342.070196] ? register_netdevice_notifier+0x790/0x790 [ 342.070196] ? __local_bh_enable_ip+0xe9/0x1b0 [ 342.070196] ? __local_bh_enable_ip+0xe9/0x1b0 [ 342.070196] ? clusterip_tg_destroy+0x372/0x650 [ipt_CLUSTERIP] [ 342.070196] ? trace_hardirqs_on+0x93/0x210 [ 342.070196] ? __bpf_trace_preemptirq_template+0x10/0x10 [ 342.070196] ? clusterip_tg_destroy+0x372/0x650 [ipt_CLUSTERIP] [ 342.123094] clusterip_tg_destroy+0x3ad/0x650 [ipt_CLUSTERIP] [ 342.123094] ? clusterip_net_init+0x3d0/0x3d0 [ipt_CLUSTERIP] [ 342.123094] ? cleanup_match+0x17d/0x200 [ip_tables] [ 342.123094] ? xt_unregister_table+0x215/0x300 [x_tables] [ 342.123094] ? kfree+0xe2/0x2a0 [ 342.123094] cleanup_entry+0x1d5/0x2f0 [ip_tables] [ 342.123094] ? cleanup_match+0x200/0x200 [ip_tables] [ 342.123094] __ipt_unregister_table+0x9b/0x1a0 [ip_tables] [ 342.123094] iptable_filter_net_exit+0x43/0x80 [iptable_filter] [ 342.123094] ops_exit_list.isra.10+0x94/0x140 [ 342.123094] cleanup_net+0x45b/0x900 [ ... ]
Fixes: 202f59afd441 ("netfilter: ipt_CLUSTERIP: do not hold dev") Signed-off-by: Taehee Yoo ap420073@gmail.com Signed-off-by: Pablo Neira Ayuso pablo@netfilter.org Signed-off-by: Sasha Levin sashal@kernel.org --- net/ipv4/netfilter/ipt_CLUSTERIP.c | 155 ++++++++++++++++------------- 1 file changed, 87 insertions(+), 68 deletions(-)
diff --git a/net/ipv4/netfilter/ipt_CLUSTERIP.c b/net/ipv4/netfilter/ipt_CLUSTERIP.c index 33491cb6b9d1..fb1e7f237f53 100644 --- a/net/ipv4/netfilter/ipt_CLUSTERIP.c +++ b/net/ipv4/netfilter/ipt_CLUSTERIP.c @@ -57,17 +57,14 @@ struct clusterip_config { enum clusterip_hashmode hash_mode; /* which hashing mode */ u_int32_t hash_initval; /* hash initialization */ struct rcu_head rcu; - + struct net *net; /* netns for pernet list */ char ifname[IFNAMSIZ]; /* device ifname */ - struct notifier_block notifier; /* refresh c->ifindex in it */ };
#ifdef CONFIG_PROC_FS static const struct file_operations clusterip_proc_fops; #endif
-static unsigned int clusterip_net_id __read_mostly; - struct clusterip_net { struct list_head configs; /* lock protects the configs list */ @@ -78,16 +75,30 @@ struct clusterip_net { #endif };
+static unsigned int clusterip_net_id __read_mostly; +static inline struct clusterip_net *clusterip_pernet(struct net *net) +{ + return net_generic(net, clusterip_net_id); +} + static inline void clusterip_config_get(struct clusterip_config *c) { refcount_inc(&c->refcount); }
- static void clusterip_config_rcu_free(struct rcu_head *head) { - kfree(container_of(head, struct clusterip_config, rcu)); + struct clusterip_config *config; + struct net_device *dev; + + config = container_of(head, struct clusterip_config, rcu); + dev = dev_get_by_name(config->net, config->ifname); + if (dev) { + dev_mc_del(dev, config->clustermac); + dev_put(dev); + } + kfree(config); }
static inline void @@ -101,9 +112,9 @@ clusterip_config_put(struct clusterip_config *c) * entry(rule) is removed, remove the config from lists, but don't free it * yet, since proc-files could still be holding references */ static inline void -clusterip_config_entry_put(struct net *net, struct clusterip_config *c) +clusterip_config_entry_put(struct clusterip_config *c) { - struct clusterip_net *cn = net_generic(net, clusterip_net_id); + struct clusterip_net *cn = clusterip_pernet(c->net);
local_bh_disable(); if (refcount_dec_and_lock(&c->entries, &cn->lock)) { @@ -118,8 +129,6 @@ clusterip_config_entry_put(struct net *net, struct clusterip_config *c) spin_unlock(&cn->lock); local_bh_enable();
- unregister_netdevice_notifier(&c->notifier); - return; } local_bh_enable(); @@ -129,7 +138,7 @@ static struct clusterip_config * __clusterip_config_find(struct net *net, __be32 clusterip) { struct clusterip_config *c; - struct clusterip_net *cn = net_generic(net, clusterip_net_id); + struct clusterip_net *cn = clusterip_pernet(net);
list_for_each_entry_rcu(c, &cn->configs, list) { if (c->clusterip == clusterip) @@ -181,32 +190,37 @@ clusterip_netdev_event(struct notifier_block *this, unsigned long event, void *ptr) { struct net_device *dev = netdev_notifier_info_to_dev(ptr); + struct net *net = dev_net(dev); + struct clusterip_net *cn = clusterip_pernet(net); struct clusterip_config *c;
- c = container_of(this, struct clusterip_config, notifier); - switch (event) { - case NETDEV_REGISTER: - if (!strcmp(dev->name, c->ifname)) { - c->ifindex = dev->ifindex; - dev_mc_add(dev, c->clustermac); - } - break; - case NETDEV_UNREGISTER: - if (dev->ifindex == c->ifindex) { - dev_mc_del(dev, c->clustermac); - c->ifindex = -1; - } - break; - case NETDEV_CHANGENAME: - if (!strcmp(dev->name, c->ifname)) { - c->ifindex = dev->ifindex; - dev_mc_add(dev, c->clustermac); - } else if (dev->ifindex == c->ifindex) { - dev_mc_del(dev, c->clustermac); - c->ifindex = -1; + spin_lock_bh(&cn->lock); + list_for_each_entry_rcu(c, &cn->configs, list) { + switch (event) { + case NETDEV_REGISTER: + if (!strcmp(dev->name, c->ifname)) { + c->ifindex = dev->ifindex; + dev_mc_add(dev, c->clustermac); + } + break; + case NETDEV_UNREGISTER: + if (dev->ifindex == c->ifindex) { + dev_mc_del(dev, c->clustermac); + c->ifindex = -1; + } + break; + case NETDEV_CHANGENAME: + if (!strcmp(dev->name, c->ifname)) { + c->ifindex = dev->ifindex; + dev_mc_add(dev, c->clustermac); + } else if (dev->ifindex == c->ifindex) { + dev_mc_del(dev, c->clustermac); + c->ifindex = -1; + } + break; } - break; } + spin_unlock_bh(&cn->lock);
return NOTIFY_DONE; } @@ -215,30 +229,44 @@ static struct clusterip_config * clusterip_config_init(struct net *net, const struct ipt_clusterip_tgt_info *i, __be32 ip, const char *iniface) { - struct clusterip_net *cn = net_generic(net, clusterip_net_id); + struct clusterip_net *cn = clusterip_pernet(net); struct clusterip_config *c; + struct net_device *dev; int err;
+ if (iniface[0] == '\0') { + pr_info("Please specify an interface name\n"); + return ERR_PTR(-EINVAL); + } + c = kzalloc(sizeof(*c), GFP_ATOMIC); if (!c) return ERR_PTR(-ENOMEM);
- strcpy(c->ifname, iniface); - c->ifindex = -1; - c->clusterip = ip; + dev = dev_get_by_name(net, iniface); + if (!dev) { + pr_info("no such interface %s\n", iniface); + kfree(c); + return ERR_PTR(-ENOENT); + } + c->ifindex = dev->ifindex; + strcpy(c->ifname, dev->name); memcpy(&c->clustermac, &i->clustermac, ETH_ALEN); + dev_mc_add(dev, c->clustermac); + dev_put(dev); + + c->clusterip = ip; c->num_total_nodes = i->num_total_nodes; clusterip_config_init_nodelist(c, i); c->hash_mode = i->hash_mode; c->hash_initval = i->hash_initval; + c->net = net; refcount_set(&c->refcount, 1);
spin_lock_bh(&cn->lock); if (__clusterip_config_find(net, ip)) { - spin_unlock_bh(&cn->lock); - kfree(c); - - return ERR_PTR(-EBUSY); + err = -EBUSY; + goto out_config_put; }
list_add_rcu(&c->list, &cn->configs); @@ -260,22 +288,17 @@ clusterip_config_init(struct net *net, const struct ipt_clusterip_tgt_info *i, } #endif
- c->notifier.notifier_call = clusterip_netdev_event; - err = register_netdevice_notifier(&c->notifier); - if (!err) { - refcount_set(&c->entries, 1); - return c; - } + refcount_set(&c->entries, 1); + return c;
#ifdef CONFIG_PROC_FS - proc_remove(c->pde); err: #endif spin_lock_bh(&cn->lock); list_del_rcu(&c->list); +out_config_put: spin_unlock_bh(&cn->lock); clusterip_config_put(c); - return ERR_PTR(err); }
@@ -475,21 +498,6 @@ static int clusterip_tg_check(const struct xt_tgchk_param *par) &e->ip.dst.s_addr); return -EINVAL; } else { - struct net_device *dev; - - if (e->ip.iniface[0] == '\0') { - pr_info("Please specify an interface name\n"); - return -EINVAL; - } - - dev = dev_get_by_name(par->net, e->ip.iniface); - if (!dev) { - pr_info("no such interface %s\n", - e->ip.iniface); - return -ENOENT; - } - dev_put(dev); - config = clusterip_config_init(par->net, cipinfo, e->ip.dst.s_addr, e->ip.iniface); @@ -503,7 +511,7 @@ static int clusterip_tg_check(const struct xt_tgchk_param *par) if (ret < 0) { pr_info("cannot load conntrack support for proto=%u\n", par->family); - clusterip_config_entry_put(par->net, config); + clusterip_config_entry_put(config); clusterip_config_put(config); return ret; } @@ -525,7 +533,7 @@ static void clusterip_tg_destroy(const struct xt_tgdtor_param *par)
/* if no more entries are referencing the config, remove it * from the list and destroy the proc entry */ - clusterip_config_entry_put(par->net, cipinfo->config); + clusterip_config_entry_put(cipinfo->config);
clusterip_config_put(cipinfo->config);
@@ -807,7 +815,7 @@ static const struct file_operations clusterip_proc_fops = {
static int clusterip_net_init(struct net *net) { - struct clusterip_net *cn = net_generic(net, clusterip_net_id); + struct clusterip_net *cn = clusterip_pernet(net); int ret;
INIT_LIST_HEAD(&cn->configs); @@ -832,7 +840,7 @@ static int clusterip_net_init(struct net *net)
static void clusterip_net_exit(struct net *net) { - struct clusterip_net *cn = net_generic(net, clusterip_net_id); + struct clusterip_net *cn = clusterip_pernet(net); #ifdef CONFIG_PROC_FS proc_remove(cn->procdir); cn->procdir = NULL; @@ -847,6 +855,10 @@ static struct pernet_operations clusterip_net_ops = { .size = sizeof(struct clusterip_net), };
+struct notifier_block cip_netdev_notifier = { + .notifier_call = clusterip_netdev_event +}; + static int __init clusterip_tg_init(void) { int ret; @@ -859,11 +871,17 @@ static int __init clusterip_tg_init(void) if (ret < 0) goto cleanup_subsys;
+ ret = register_netdevice_notifier(&cip_netdev_notifier); + if (ret < 0) + goto unregister_target; + pr_info("ClusterIP Version %s loaded successfully\n", CLUSTERIP_VERSION);
return 0;
+unregister_target: + xt_unregister_target(&clusterip_tg_reg); cleanup_subsys: unregister_pernet_subsys(&clusterip_net_ops); return ret; @@ -873,6 +891,7 @@ static void __exit clusterip_tg_exit(void) { pr_info("ClusterIP Version %s unloading\n", CLUSTERIP_VERSION);
+ unregister_netdevice_notifier(&cip_netdev_notifier); xt_unregister_target(&clusterip_tg_reg); unregister_pernet_subsys(&clusterip_net_ops);