mmap64 with very large offset broken since glibc 2.26 (MIPS64 n32)

[Florian Weimer]

* Andrew Pinski:

>> For the patch itself, the only issue is I can't really create a
>> workable test without relying on something arch-specific.  The
>> /dev/mem is tricky, it requires root access and it no portable
>> (not all architectures support that range of VMA).  Same for a sparse
>> file of such size to trigger the issue, most FS don't support files
>> that large.
>
> Couldn't you use mmap on /dev/zero with the large offset for the
> testcase?

A memfd description (from memfd_create) would be worth a try as well.

XFS supports sparse files for the whole 63-bit range, too.

Thanks,
Florian