Re: [PATCH] Add audit uid to netlink credentials

[Patrick McHardy <kaber@xxxxxxxxx>]

Alexey Kuznetsov wrote:

> Hello!
>
>  
>
> > if (down_trylock(&audit_netlink_sem))
> >         return;
> >
> > with plain down(&audit_netlink_sem);
> I am sorry, this is wrong. Dequeue may happen in another process context
> in any case.
Could you explain how this can happen ? From what I can see whenever data
is queued to the receive queue the input function is called immediately
through sk->sk_data_ready() -> netlink_data_ready() -> nlk->data_ready()
and processes all queued packets, except in the case you pointed out,
when audit_netlink_sem is already taken.

Regards
Patrick