RFC PATCH: Don't use /proc/self/maps to calculate size of initial thread stack

[Florian Weimer]

* Zack Weinberg via Libc-alpha:

> On Tue, Sep 20, 2022, at 8:16 AM, Florian Weimer via Libc-alpha wrote:
>>>> Maybe we can get the kernel to pass the end of the stack in the
>>>> auxiliary vector?
>>>
>>> Sure, but then what do we do on older kernels?  I'm reluctant to say
>>> "keep the old code" because we know this is breaking for people right
>>> now (although honestly "mount /proc earlier" isn't a terrible
>>> suggestion for a workaround).
>>
>> We can keep doing what we are doing on older kernels.  I don't think we
>> should add yet another fallback path for this in case /proc isn't
>> available and the kernel doesn't provide the (future) AT_* entry.  *Two*
>> fallback paths instead of one seems a bit over the top.
>
> Fair enough.  I have no experience writing kernel patches, do you know
> anyone who can make the additional AT entry happen?

Sorry, no idea.  The easiest way to get people's attention seems to be,
post a slightly broken patch to fs/binfmt_elf.c.

Thanks,
Florian