Re: [RFC PATCH ghak10 v6 2/2] ntp: Audit NTP parameters adjustment

From: Thomas Gleixner
Date: Tue Apr 02 2019 - 05:03:20 EST


On Mon, 1 Apr 2019, Ondrej Mosnacek wrote:
> On Thu, Mar 28, 2019 at 1:02 AM Thomas Gleixner <tglx@xxxxxxxxxxxxx> wrote:
> > On Thu, 7 Mar 2019, Ondrej Mosnacek wrote:
> > > /* adjtime() is independent from ntp_adjtime() */
> > > time_adjust = txc->offset;
> > > ntp_update_frequency();
> > > +
> > > + audit_ntp_adjust("adjust", save_adjust, txc->offset);
> > > }
> > > txc->offset = save_adjust;
> > > } else {
> >
> > Not going to happen. We are not reshuffling all that code just to
> > accomodate random audit log invocations in a critical section plus having a
> > gazillion of GFP_ATOMIC allocation in the critical section just because.
>
> OK, seems I underestimated the consequences of putting the logging
> calls directly in there. While I was offline over the weekend I
> already came up with a cleaner version that collects the changes in a
> structure and does the logging outside of the critical section. I
> currently does a few unnecessary writes into memory under
> CONFIG_AUDIT=n, but if that is an issue I can boost the abstraction or
> just add some #ifdefs to avoid that.

No ifdefs please. Aside of that, why do you need all those details of the
ntp internals in the first place? The changelog does not give me an answer
to that.

Thanks,

tglx