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

[Guenter Roeck <linux@roeck-us.net>]

On 3/23/22 05:10, Mark Brown wrote:
> On Tue, Mar 22, 2022 at 02:54:20PM -0700, Guenter Roeck wrote:
>> On 3/22/22 11:24, Mark Brown wrote:
> 
>>> Just as a datapoint for debugging at least qemu/arm is getting coverage
>>> in CI systems (KernelCI is covering a bunch of different emulated
>>> machines and LKFT has at least one configuration as well, clang's tests
>>> have some wider architecture coverage as well I think) and they don't
>>> seem to be seeing any problems - there's some other variable in there.
> 
>> I use buildroot 2021.02.3. I have not changed the buildroot code, and it
>> still seems to be the same in 2022.02. I don't see the problem with all
>> boot tests, only with the architectures mentioned above, and not with all
>> qemu machines on the affected platforms. For arm, mostly older machines
>> are affected (versatile, realview, pxa configurations, collie, integratorcp,
>> sx1, mps2-an385, vexpress-a9, cubieboard). I didn't check, but maybe
>> kernelci doesn't test those machines ?
> 
> Kind of academic given that Jason seems to have a handle on what the
> issues are but for KernelCI it's variations on mach-virt, plus
> versatile-pb.  There's a physical cubietruck as well, and BeagleBone
> Blacks among others.  My best guess would be systems with low RAM are
> somehow more prone to issues.

I don't think it is entirely academic. versatile-pb fails for me;
if it doesn't fail at KernelCI, I'd like to understand why - not to
fix it in my test environment, but to make sure that I _don't_ fix it.
After all, it _is_ a regression. Even if that regression is triggered
by bad (for a given definition of "bad") userspace code, it is still
a regression.

Thanks,
Guenter