diff options
| author | stephen hemminger <shemminger@vyatta.com> | 2010-07-22 18:45:04 +0000 |
|---|---|---|
| committer | David S. Miller <davem@davemloft.net> | 2010-07-24 21:04:20 -0700 |
| commit | 3b87956ea645fb4de7e59c7d0aa94de04be72615 (patch) | |
| tree | 0dde04e6dfad7cd76afbb31eff72a8f08a574a9c /net/sched | |
| parent | 76ac21f5ef30e46397e405695eb1240ff0955209 (diff) | |
net sched: fix race in mirred device removal
This fixes hang when target device of mirred packet classifier
action is removed.
If a mirror or redirection action is configured to cause packets
to go to another device, the classifier holds a ref count, but was assuming
the adminstrator cleaned up all redirections before removing. The fix
is to add a notifier and cleanup during unregister.
The new list is implicitly protected by RTNL mutex because
it is held during filter add/delete as well as notifier.
Signed-off-by: Stephen Hemminger <shemminger@vyatta.com>
Acked-by: Jamal Hadi Salim <hadi@cyberus.ca>
Signed-off-by: David S. Miller <davem@davemloft.net>
Diffstat (limited to 'net/sched')
| -rw-r--r-- | net/sched/act_mirred.c | 43 |
1 files changed, 40 insertions, 3 deletions
diff --git a/net/sched/act_mirred.c b/net/sched/act_mirred.c index c0b6863e3b87..1980b71c283f 100644 --- a/net/sched/act_mirred.c +++ b/net/sched/act_mirred.c @@ -33,6 +33,7 @@ static struct tcf_common *tcf_mirred_ht[MIRRED_TAB_MASK + 1]; static u32 mirred_idx_gen; static DEFINE_RWLOCK(mirred_lock); +static LIST_HEAD(mirred_list); static struct tcf_hashinfo mirred_hash_info = { .htab = tcf_mirred_ht, @@ -47,7 +48,9 @@ static inline int tcf_mirred_release(struct tcf_mirred *m, int bind) m->tcf_bindcnt--; m->tcf_refcnt--; if(!m->tcf_bindcnt && m->tcf_refcnt <= 0) { - dev_put(m->tcfm_dev); + list_del(&m->tcfm_list); + if (m->tcfm_dev) + dev_put(m->tcfm_dev); tcf_hash_destroy(&m->common, &mirred_hash_info); return 1; } @@ -134,8 +137,10 @@ static int tcf_mirred_init(struct nlattr *nla, struct nlattr *est, m->tcfm_ok_push = ok_push; } spin_unlock_bh(&m->tcf_lock); - if (ret == ACT_P_CREATED) + if (ret == ACT_P_CREATED) { + list_add(&m->tcfm_list, &mirred_list); tcf_hash_insert(pc, &mirred_hash_info); + } return ret; } @@ -162,9 +167,14 @@ static int tcf_mirred(struct sk_buff *skb, struct tc_action *a, m->tcf_tm.lastuse = jiffies; dev = m->tcfm_dev; + if (!dev) { + printk_once(KERN_NOTICE "tc mirred: target device is gone\n"); + goto out; + } + if (!(dev->flags & IFF_UP)) { if (net_ratelimit()) - pr_notice("tc mirred to Houston: device %s is gone!\n", + pr_notice("tc mirred to Houston: device %s is down\n", dev->name); goto out; } @@ -232,6 +242,28 @@ nla_put_failure: return -1; } +static int mirred_device_event(struct notifier_block *unused, + unsigned long event, void *ptr) +{ + struct net_device *dev = ptr; + struct tcf_mirred *m; + + if (event == NETDEV_UNREGISTER) + list_for_each_entry(m, &mirred_list, tcfm_list) { + if (m->tcfm_dev == dev) { + dev_put(dev); + m->tcfm_dev = NULL; + } + } + + return NOTIFY_DONE; +} + +static struct notifier_block mirred_device_notifier = { + .notifier_call = mirred_device_event, +}; + + static struct tc_action_ops act_mirred_ops = { .kind = "mirred", .hinfo = &mirred_hash_info, @@ -252,12 +284,17 @@ MODULE_LICENSE("GPL"); static int __init mirred_init_module(void) { + int err = register_netdevice_notifier(&mirred_device_notifier); + if (err) + return err; + pr_info("Mirror/redirect action on\n"); return tcf_register_action(&act_mirred_ops); } static void __exit mirred_cleanup_module(void) { + unregister_netdevice_notifier(&mirred_device_notifier); tcf_unregister_action(&act_mirred_ops); } |