Patrick McHardy wrote:
> Pavel Emelianov wrote:
>> From: Denis Lunev <[EMAIL PROTECTED]>
>>
>> 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.
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