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authorStephen Hemminger <shemminger@osdl.org>2006-04-12 14:52:54 -0700
committerGreg Kroah-Hartman <gregkh@suse.de>2006-04-17 13:16:06 -0700
commit23e0ac040b8052729c32dfec78f751d82515e73e (patch)
tree1dcc434a1b466ebce512c1c240cd27f6cdd02394
parent18b1e8193eef97f3ac854276a7c4bacbb1bdfbd1 (diff)
[PATCH] atm: clip causes unregister hang
If Classical IP over ATM module is loaded, its neighbor table gets populated when permanent neighbor entries are created; but these entries are not flushed when the device is removed. Since the entry never gets flushed the unregister of the network device never completes. This version of the patch also adds locking around the reference to the atm arp daemon to avoid races with events and daemon state changes. (Note: barrier() was never really safe) Bug-reference: http://bugzilla.kernel.org/show_bug.cgi?id=6295 Signed-off-by: Stephen Hemminger <shemminger@osdl.org> Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
-rw-r--r--net/atm/clip.c42
1 files changed, 27 insertions, 15 deletions
diff --git a/net/atm/clip.c b/net/atm/clip.c
index 73370de97539..1842a4ef9cb8 100644
--- a/net/atm/clip.c
+++ b/net/atm/clip.c
@@ -613,12 +613,19 @@ static int clip_create(int number)
static int clip_device_event(struct notifier_block *this,unsigned long event,
- void *dev)
+ void *arg)
{
+ struct net_device *dev = arg;
+
+ if (event == NETDEV_UNREGISTER) {
+ neigh_ifdown(&clip_tbl, dev);
+ return NOTIFY_DONE;
+ }
+
/* ignore non-CLIP devices */
- if (((struct net_device *) dev)->type != ARPHRD_ATM ||
- ((struct net_device *) dev)->hard_start_xmit != clip_start_xmit)
+ if (dev->type != ARPHRD_ATM || dev->hard_start_xmit != clip_start_xmit)
return NOTIFY_DONE;
+
switch (event) {
case NETDEV_UP:
DPRINTK("clip_device_event NETDEV_UP\n");
@@ -686,14 +693,12 @@ static struct notifier_block clip_inet_notifier = {
static void atmarpd_close(struct atm_vcc *vcc)
{
DPRINTK("atmarpd_close\n");
- atmarpd = NULL; /* assumed to be atomic */
- barrier();
- unregister_inetaddr_notifier(&clip_inet_notifier);
- unregister_netdevice_notifier(&clip_dev_notifier);
- if (skb_peek(&sk_atm(vcc)->sk_receive_queue))
- printk(KERN_ERR "atmarpd_close: closing with requests "
- "pending\n");
+
+ rtnl_lock();
+ atmarpd = NULL;
skb_queue_purge(&sk_atm(vcc)->sk_receive_queue);
+ rtnl_unlock();
+
DPRINTK("(done)\n");
module_put(THIS_MODULE);
}
@@ -714,7 +719,12 @@ static struct atm_dev atmarpd_dev = {
static int atm_init_atmarp(struct atm_vcc *vcc)
{
- if (atmarpd) return -EADDRINUSE;
+ rtnl_lock();
+ if (atmarpd) {
+ rtnl_unlock();
+ return -EADDRINUSE;
+ }
+
if (start_timer) {
start_timer = 0;
init_timer(&idle_timer);
@@ -731,10 +741,7 @@ static int atm_init_atmarp(struct atm_vcc *vcc)
vcc->push = NULL;
vcc->pop = NULL; /* crash */
vcc->push_oam = NULL; /* crash */
- if (register_netdevice_notifier(&clip_dev_notifier))
- printk(KERN_ERR "register_netdevice_notifier failed\n");
- if (register_inetaddr_notifier(&clip_inet_notifier))
- printk(KERN_ERR "register_inetaddr_notifier failed\n");
+ rtnl_unlock();
return 0;
}
@@ -992,6 +999,8 @@ static int __init atm_clip_init(void)
clip_tbl_hook = &clip_tbl;
register_atm_ioctl(&clip_ioctl_ops);
+ register_netdevice_notifier(&clip_dev_notifier);
+ register_inetaddr_notifier(&clip_inet_notifier);
#ifdef CONFIG_PROC_FS
{
@@ -1012,6 +1021,9 @@ static void __exit atm_clip_exit(void)
remove_proc_entry("arp", atm_proc_root);
+ unregister_inetaddr_notifier(&clip_inet_notifier);
+ unregister_netdevice_notifier(&clip_dev_notifier);
+
deregister_atm_ioctl(&clip_ioctl_ops);
/* First, stop the idle timer, so it stops banging