locks and kernel randomness...

[John-Mark Gurney]

Warner Losh wrote this message on Tue, Feb 24, 2015 at 11:03 -0700:
> 
> > On Feb 24, 2015, at 10:40 AM, John-Mark Gurney <jmg at funkthat.com> wrote:
> > 
> > Warner Losh wrote this message on Tue, Feb 24, 2015 at 07:56 -0700:
> >> Then again, if you want to change random(), provide a weak_random() that???s
> >> the traditional non-crypto thing that???s fast and lockless. That would make it easy
> >> to audit in our tree. The scheduler doesn???t need cryptographic randomness, it
> >> just needs to make different choices sometimes to ensure its notion of fairness.
> > 
> > I do not support having a weak_random...  If the consumer is sure
> > enough that you don't need a secure random, then they can pick an LCG
> > and implement it themselves and deal (or not) w/ the locking issues...
> > 
> > It appears that the scheduler had an LCG but for some reason the authors
> > didn't feel like using it here..
> 
> Why don???t you support having a common random routine that???s to mix the
> pot, but not cryptographically secure? Lots of algorithms use them, and having
> a common one would keep us from reinventing the wheel.

Why can't these algorithms use a cryptographically secure RNG instead?
No one has truely answered that point..  Everyone says they want to use
an insecure RNG, but the real question is, why can't/shouldn't these
algorithms use a CSPRNG?

-- 
  John-Mark Gurney				Voice: +1 415 225 5579

     "All that I will do, has been done, All that I have, has not."