Re: Linux 5.3-rc8

[Ahmed S. Darwish]

On Wed, Sep 11, 2019 at 11:41:44PM +0200, Ahmed S. Darwish wrote:
> On Wed, Sep 11, 2019 at 05:45:38PM +0100, Linus Torvalds wrote:
[...]
> >
> > Well, even on a PC, sometimes rdrand just isn't there. AMD has screwed
> > it up a few times, and older Intel chips just don't have it.
> > 
> > So I'd be inclined to either lower the limit regardless -
> 
> ACK :)
> 
> > and perhaps make the "user space asked for randomness much too
> > early" be a big *warning* instead of being a basically fatal hung
> > machine?
> 
> Hmmm, regarding "randomness request much too early", how much is time
> really a factor here?
> 
> I tested leaving the machine even for 15+ minutes, and it still didn't
> continue booting: the boot is practically blocked forever...
> 
> Or is the thoery that hopefully once the machine is un-stuck, more
> sources of entropy will be available? If that's the case, then
> possibly (rate-limited):
> 
>   "urandom: process XX asked for YY bytes. CRNG not yet initialized"
>
     ^
     getrandom: ....

(since urandom always succeeds, even if CRNG is not inited, and
 it already prints a very similar warning in that case anyway..)

thanks,
--darwi