Re: [Xen-devel] [PATCH] xen/netback: Fix null-pointer access in netback_uevent

[Bastian Blank <waldi@xxxxxxxxxx>]

On Thu, Jul 29, 2010 at 02:44:36PM +0100, Ian Campbell wrote:
> On Thu, 2010-07-29 at 13:42 +0100, Bastian Blank wrote:
> > Yes, this is included since 2.6.32-15.
> The patch from <20100529184452.GA18365@xxxxxxxxxxxxxxxxxxxxxxx>?

Currently the following patch is used. The next test should be if it is
really necessary to have this much different structures, a quick look
said: most likely no.

diff --git a/drivers/xen/netback/xenbus.c b/drivers/xen/netback/xenbus.c
index 99831c7..1930f64 100644
--- a/drivers/xen/netback/xenbus.c
+++ b/drivers/xen/netback/xenbus.c
@@ -162,17 +162,11 @@ fail:
  */
 static int netback_uevent(struct xenbus_device *xdev, struct kobj_uevent_env 
*env)
 {
-       struct backend_info *be;
-       struct xen_netif *netif;
+       struct backend_info *be = dev_get_drvdata(&xdev->dev);
        char *val;
 
        DPRINTK("netback_uevent");
 
-       be = dev_get_drvdata(&xdev->dev);
-       if (!be)
-               return 0;
-       netif = be->netif;
-
        val = xenbus_read(XBT_NIL, xdev->nodename, "script", NULL);
        if (IS_ERR(val)) {
                int err = PTR_ERR(val);
@@ -187,7 +181,7 @@ static int netback_uevent(struct xenbus_device *xdev, 
struct kobj_uevent_env *en
                kfree(val);
        }
 
-       if (add_uevent_var(env, "vif=%s", netif->dev->name))
+       if (be && be->netif && add_uevent_var(env, "vif=%s", 
be->netif->dev->name))
                return -ENOMEM;
 
        return 0;

-- 
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