aboutsummaryrefslogtreecommitdiff
path: root/net
diff options
context:
space:
mode:
authorstephen hemminger <shemminger@vyatta.com>2010-07-22 18:45:04 +0000
committerDavid S. Miller <davem@davemloft.net>2010-07-24 21:04:20 -0700
commit3b87956ea645fb4de7e59c7d0aa94de04be72615 (patch)
tree0dde04e6dfad7cd76afbb31eff72a8f08a574a9c /net
parent76ac21f5ef30e46397e405695eb1240ff0955209 (diff)
downloadlinux-2.6.34-ux500-3b87956ea645fb4de7e59c7d0aa94de04be72615.tar.gz
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')
-rw-r--r--net/sched/act_mirred.c43
1 files changed, 40 insertions, 3 deletions
diff --git a/net/sched/act_mirred.c b/net/sched/act_mirred.c
index c0b6863e3b8..1980b71c283 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);
}