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@xxxxxxxxx>
---
net/ipv4/netfilter/ipt_CLUSTERIP.c | 71 +++++++++++++++++-------------
1 file changed, 40 insertions(+), 31 deletions(-)
diff --git a/net/ipv4/netfilter/ipt_CLUSTERIP.c b/net/ipv4/netfilter/ipt_CLUSTERIP.c
index 2c8d313ae216..6ccabe6f74a6 100644
--- a/net/ipv4/netfilter/ipt_CLUSTERIP.c
+++ b/net/ipv4/netfilter/ipt_CLUSTERIP.c
@@ -59,7 +59,6 @@ struct clusterip_config {
struct rcu_head rcu;
char ifname[IFNAMSIZ]; /* device ifname */
- struct notifier_block notifier; /* refresh c->ifindex in it */
};
#ifdef CONFIG_PROC_FS
@@ -118,8 +117,6 @@ 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();
@@ -181,32 +178,37 @@ 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 = net_generic(net, clusterip_net_id);
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(&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(&cn->lock);
return NOTIFY_DONE;
}
@@ -260,12 +262,8 @@ 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);
@@ -847,6 +845,10 @@ 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 +861,17 @@ 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 +881,7 @@ 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);
--
2.17.1
