Re: [PATCH v1] random: block in /dev/urandom

Guenter Roeck
2022-03-22T18:19:21Z

On 3/22/22 10:09, Jason A. Donenfeld wrote:
> Hey Guenter,
>
> On Tue, Mar 22, 2022 at 08:58:20AM -0700, Guenter Roeck wrote:
>> On Thu, Feb 17, 2022 at 05:28:48PM +0100, Jason A. Donenfeld wrote:
>>> This topic has come up countless times, and usually doesn't go anywhere.
>>> This time I thought I'd bring it up with a slightly narrower focus,
>>> updated for some developments over the last three years: we finally can
>>> make /dev/urandom always secure, in light of the fact that our RNG is
>>> now always seeded.
>>>
>>
>> [ ... ]
>>
>> This patch (or a later version of it) made it into mainline and causes a
>> large number of qemu boot test failures for various architectures (arm,
>> m68k, microblaze, sparc32, xtensa are the ones I observed). Common
>> denominator is that boot hangs at "Saving random seed:". A sample bisect
>> log is attached. Reverting this patch fixes the problem.
>
> As Linus said, it was worth a try, but I guess it just didn't work. For
> my own curiosity, though, do you have a link to those QEMU VMs you could
> share? I'd sort of like to poke around, and if we do ever reattempt this
> sometime down the road, it seems like understanding everything about why
> the previous time failed might be a good idea.
>

Everything - including the various root file systems - is at
git@github.com:groeck/linux-build-test.git. Look into rootfs/ for the
various boot tests. I'll be happy to provide some qemu command lines
if needed.

Guenter