svn commit: r284959 - in head: . share/man/man4 share/man/man9 sys/conf sys/dev/glxsb sys/dev/hifn sys/dev/random sys/dev/rndtest sys/dev/safe sys/dev/syscons sys/dev/ubsec sys/dev/virtio/random sy...

[Adrian Chadd]

hi,

So I'll have to update the AP images that I build, as now I have to
add that sysctl to things.

It also means everyone has to update their /etc after updating or
they'll end up with this particular mode not being disabled.

i think we need to get this better documented so people aren't bitten
when they merge code in from -HEAD or whenever you do MFC this back to
stable/10.



-adrian

On 16 July 2015 at 16:14, K. Macy <kmacy at freebsd.org> wrote:
> On Thu, Jul 16, 2015 at 3:28 PM, K. Macy <kmacy at freebsd.org> wrote:
>> I discovered this when I MFC'd and my kernel wouldn't link because of
>> unresolved symbols. I thought I had put the issue aside when I added
>> RANDOM_DUMMY to my kernel config.
>>
>> However, I just hit this:
>>
>>         while (!random_alg_context.ra_seeded()) {
>>                 if (nonblock) {
>>                         error = EWOULDBLOCK;
>>                         break;
>>                 }
>>                 tsleep(&random_alg_context, 0, "randseed", hz/10);
>>                 /* keep tapping away at the pre-read until we seed/unblock. */
>>                 random_alg_context.ra_pre_read();
>>                 printf("random: %s unblock wait\n", __func__);
>>         }
>>
>> My system wouldn't boot because this was endlessly spamming the
>> console. I don't know what the right default here is. But I can say
>> that this is not it.
>
>
> I've also realized that a process blocked here is uninterruptible.
> Hence any process reading an insufficiently seeded /dev/random is
> unkillable. For example my boot can't proceed past dd doing a read and
> I can't ^C it. Did you test RANDOM_DUMMY?
>
>
> -K
>