Re: [yocto] Y2038 proposal

[Lukasz Majewski <lukma@denx.de>]

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Hi Alexander,

> On Tue, 29 Nov 2022 at 16:45, Stephen Jolley
> <sjolley.yp.pm@gmail.com> wrote:
> > We’d welcome a proposal/series on how to move forward with the
> > Y2038 work for 32 bit platforms.  
> 
> I have the following proposal:
> 
> 1. A branch is made where:
> a. "-D_TIME_BITS=64 -D_FILE_OFFSET_BITS=64" is enabled globally.
> b. qemu is always started with "-rtc base=2040-01-01", simulating
> Y2038 actually occurring.
> c. an additional runtime test verifies that both RTC clock and system
> clock report 2040.
> 

Please find a few comments:

1. There is already provided meta-y2038 [1] to test if 32 bit systems
correctly support Y2038 problem. It uses qemu machines from OE/Yocto

2. There are ptest available [2] to validate if the Y2038 problem works
correctly.

3. Support for running ptests mentioned in point 2. is already
available in the poky repository [3].



> 2. This branch is run through a-full on the autobuilder. Any uncovered
> issues are filed as bugs.
> 
> 3. Once *all* of the bugs are addressed, repeat point 2.
> 
> 4. Once there are no more open bugs, 1a is merged into master.
> 
> Any fatal flaws in the plan?
> 
> It's not hard to see that Y2038 problem is real and serious, e.g. on
> qemux86 core-image-full-cmdline built from master:
> 
> root@qemux86:~# ls /
> bin  boot  dev    etc  home  lib    lost+found  media  mnt    proc
> run  sbin  sys  tmp  usr    var
> root@qemux86:~# date -s "2040-01-01"
> Sun Jan  1 00:00:00 UTC 2040
> root@qemux86:~# ls /
> bin  boot  dev    etc  home  lib    lost+found  media  mnt    proc
> run  sbin  sys  tmp  usr    var
> root@qemux86:~# ls /
> -sh: ls: command not found
> 
> On qemux86_64 the same sequence works as expected, of course.
> 

Yes, y2038 is an important issue.

I would be more than happy if we could reuse the previous work [1].

I've used OE/Yocto to validate the code during developing support for
'-D_TIME_BITS=64 ' flag in glibc.

It looks like the meta-y2038 can be used out of the box (after checking
if it still works with newest poky) when added to the Yocto Project
build/test infrastructure.


> Alex

Links:

[1] - https://github.com/lmajewski/meta-y2038
[2] - https://github.com/lmajewski/meta-y2038/blob/master/README#L201
[3] -
https://git.yoctoproject.org/poky/commit/?id=0e0c481a25f10f8f7ff1d69bda7f015186da0202


Best regards,

Lukasz Majewski

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