Re: [Y2038][time namespaces] Question regarding CLOCK_REALTIME support plans in Linux time namespaces

[Thomas Gleixner]

On Fri, Oct 30 2020 at 10:02, Zack Weinberg wrote:
> On Fri, Oct 30, 2020 at 9:57 AM Cyril Hrubis <chrubis@xxxxxxx> wrote:
>> > According to patch description [1] and time_namespaces documentation
>> > [2] the CLOCK_REALTIME is not supported (for now?) to avoid complexity
>> > and overhead in the kernel.
> ...
>> > To be more specific - [if this were supported] it would be possible to modify time after time_t
>> > 32 bit overflow (i.e. Y2038 bug) on the process running Y2038
>> > regression tests on the host system (64 bit one). By using Linux time
>> > namespaces the system time will not be affected in any way.
>>
>> And what's exactly wrong with moving the system time forward for a
>> duration of the test?
>
> Interference with other processes on the same computer?  Some of us
> *do* like to run the glibc test suite on computers not entirely
> devoted to glibc CI.

That's what virtual machines are for.