[Xen-devel] [patch] fix netfront race

[Gerd Hoffmann <kraxel@xxxxxxx>]

  Hi,

this patch moves register_netdev() + sysfs attribute
registering from create_netdev() into the new open_netdev()
function. open_netdev is called as very last thing in
netdev_probe.

This closes at least one initialization race: uninitialized
mac address is visible for a short time in
/sys/class/net/${if}/address

please apply,

  Gerd

-- 
Gerd Hoffmann <kraxel@xxxxxxx>
http://www.suse.de/~kraxel/julika-dora.jpeg

move register_netdev() + sysfs attribute registering from
create_netdev() into the new open_netdev() function.
open_netdev is called as very last thing in netdev_probe.

This closes at least one initialization race: uninitialized
mac address is visible for a short time in
/sys/class/net/${if}/address

Signed-off-by: Gerd Hoffmann <kraxel@xxxxxxx>
diff -r f790546ecfda linux-2.6-xen-sparse/drivers/xen/netfront/netfront.c
--- a/linux-2.6-xen-sparse/drivers/xen/netfront/netfront.c      Mon Aug 28 
20:22:56 2006 +0100
+++ b/linux-2.6-xen-sparse/drivers/xen/netfront/netfront.c      Tue Aug 29 
09:18:23 2006 +0200
@@ -193,6 +193,7 @@ static void netfront_closing(struct xenb
 
 static void end_access(int, void *);
 static void netif_disconnect_backend(struct netfront_info *);
+static int open_netdev(struct netfront_info *);
 static void close_netdev(struct netfront_info *);
 static void netif_free(struct netfront_info *);
 
@@ -263,15 +264,22 @@ static int __devinit netfront_probe(stru
        dev->dev.driver_data = info;
 
        err = talk_to_backend(dev, info);
-       if (err) {
-               xennet_sysfs_delif(info->netdev);
-               unregister_netdev(netdev);
-               free_netdev(netdev);
-               dev->dev.driver_data = NULL;
-               return err;
-       }
+       if (err)
+               goto fail_backend;
+
+       err = open_netdev(info);
+       if (err)
+               goto fail_open;
 
        return 0;
+
+ fail_open:
+       xennet_sysfs_delif(info->netdev);
+       unregister_netdev(netdev);
+ fail_backend:
+       free_netdev(netdev);
+       dev->dev.driver_data = NULL;
+       return err;
 }
 
 
@@ -1887,27 +1895,9 @@ create_netdev(int handle, int copying_re
        SET_MODULE_OWNER(netdev);
        SET_NETDEV_DEV(netdev, &dev->dev);
 
-       err = register_netdev(netdev);
-       if (err) {
-               printk(KERN_WARNING "%s> register_netdev err=%d\n",
-                      __FUNCTION__, err);
-               goto exit_free_rx;
-       }
-
-       err = xennet_sysfs_addif(netdev);
-       if (err) {
-               /* This can be non-fatal: it only means no tuning parameters */
-               printk(KERN_WARNING "%s> add sysfs failed err=%d\n",
-                      __FUNCTION__, err);
-       }
-
        np->netdev = netdev;
-
        return netdev;
 
-
- exit_free_rx:
-       gnttab_free_grant_references(np->gref_rx_head);
  exit_free_tx:
        gnttab_free_grant_references(np->gref_tx_head);
  exit:
@@ -1966,6 +1955,26 @@ static int __devexit netfront_remove(str
        return 0;
 }
 
+
+static int open_netdev(struct netfront_info *info)
+{
+       int err;
+       
+       err = register_netdev(info->netdev);
+       if (err) {
+               printk(KERN_WARNING "%s: register_netdev err=%d\n",
+                      __FUNCTION__, err);
+               return err;
+       }
+
+       err = xennet_sysfs_addif(info->netdev);
+       if (err) {
+               /* This can be non-fatal: it only means no tuning parameters */
+               printk(KERN_WARNING "%s: add sysfs failed err=%d\n",
+                      __FUNCTION__, err);
+       }
+       return 0;
+}
 
 static void close_netdev(struct netfront_info *info)
 {

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