lkml.org 
[lkml]   [2007]   [May]   [14]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
/
Date
From
SubjectRe: [BUG][PATCH] Fix race condition about network device name allocation
On Mon, 14 May 2007 10:33:01 +0900
Kenji Kaneshige <kaneshige.kenji@jp.fujitsu.com> wrote:

> Hi Stephen,
>
> Thank you for comments. I'll try your patch.
>
> I have one concern about your patch, though I don't know very much
> about netdev codes.
>
> @@ -3411,6 +3410,9 @@ void unregister_netdevice(struct net_dev
> > /* Notifier chain MUST detach us from master device. */
> > BUG_TRAP(!dev->master);
> >
> > + /* Remove entries from sysfs */
> > + netdev_unregister_sysfs(dev);
> > +
> > /* Finish processing unregister after unlock */
> > net_set_todo(dev);
> >
>
> With your patch, the netdev_unregister_sysfs() will be called
> earlier than now. Does it have no side effect? I'm worrying
> about if there are somebody that depend on sysfs entry until
> net_run_todo() is called.


The unregister_sysfs() removes the entry in /sys/class/net and then
decrements the reference count. When ref count goes to zero, the kobject_release
callback gets called and which does kfree().

Changing the shutdown order makes the /sys/class/net entry disappear
sooner. In order to prevent the free from happening until after all the dev_put()
calls have happened, the reference count for the kobject needs to be increased.

-
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@vger.kernel.org
More majordomo info at http://vger.kernel.org/majordomo-info.html
Please read the FAQ at http://www.tux.org/lkml/

\
 
 \ /
  Last update: 2007-05-14 17:45    [W:0.109 / U:5.168 seconds]
©2003-2018 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site