OpenVZ Forum: Devel » [PATCH] Don't attach callback to a going-away netlink socket

Home » Mailing lists » Devel » [PATCH] Don't attach callback to a going-away netlink socket

Show: Today's Messages :: Show Polls :: Message Navigator
E-mail to friend

Re: [PATCH] Don't attach callback to a going-away netlink socket [message #12046 is a reply to message #12044]

Mon, 16 April 2007 11:53

xemul
Messages: 248
Registered: November 2005

Senior Member

Patrick McHardy wrote:
> Pavel Emelianov wrote:
>> From: Denis Lunev <den@openvz.org>
>>
>> There is a race between netlink_dump_start() and netlink_release()
>> that can lead to the situation when a netlink socket with non-zero
>> callback is freed.
>
>
> Can you describe the race in more detail please?
>
>

Here it is:

CPU1: CPU2
netlink_release(): netlink_dump_start():

sk = netlink_lookup(); /* OK */

netlink_remove();

spin_lock(&nlk->cb_lock);
if (nlk->cb) { /* false */
...
}
spin_unlock(&nlk->cb_lock);

spin_lock(&nlk->cb_lock);
if (nlk->cb) { /* false */
...
}
nlk->cb = cb;
spin_unlock(&nlk->cb_lock);
...
sock_orphan(sk);
/*
* proceed with releasing
* the socket
*/

The proposal it to make sock_orphan before detaching the callback
in netlink_release() and to check for the sock to be SOCK_DEAD in
netlink_dump_start() before setting a new callback.

Report message to a moderator

[Message index]

		[PATCH] Don't attach callback to a going-away netlink socket By: xemul on Mon, 16 April 2007 11:34
		Re: [PATCH] Don't attach callback to a going-away netlink socket By: Patrick McHardy on Mon, 16 April 2007 11:41
		Re: [PATCH] Don't attach callback to a going-away netlink socket By: xemul on Mon, 16 April 2007 11:53
		Re: [PATCH] Don't attach callback to a going-away netlink socket By: Patrick McHardy on Mon, 16 April 2007 12:55
		Re: [PATCH] Don't attach callback to a going-away netlink socket By: James Morris on Mon, 16 April 2007 12:37

Previous Topic:	How to query mount propagation state?
Next Topic:	[PATCH] Report that kernel is tainted if there were an OOPS before

Goto Forum:

-=] Back to Top [=-

[ Syndicate this forum (XML) ] [

] [

]

Current Time: Sun Dec 07 18:10:26 GMT 2025

Total time taken to generate the page: 0.15704 seconds