Re: Bug#1093200: Some packages consistently FTBFS with EFAULT (Bad address) on most mips64el buildds

[Sergei Golovan <sgolovan@debian.org>]

Hi!

On Wed, Jan 29, 2025 at 10:45 PM Uwe Kleine-König <ukleinek@debian.org> wrote:
>
> Hello,
>
> I agree this looks like the kernel is at least involved in this problem.
> Is someone able to do a bisect to help the kernel team to pinpoint the
> issue?
>
> Or does someone has a reproducer that also works for someone without
> mips64el hardware (probably something involving qemu)?

I've tried to reproduce the Erlang FTBFS in qemu (both on malta and
loongson-virt machines) and failed to do so.
Also, I've found a thread on linux-kernel mailing list, which might be
relevant (see [1]). It describes some EFAULT on
mips64 which were introduced roughly at the same time when Erlang
started to FTBFS. I've run the test they
suggested (on qemu on loongson-virt machine).

The test program is compiled using gcc-14 (14.2.0-16).

The test program aborts on kernels 6.1.0-29-loongson-3 (6.1.123-1) and
6.12.10-loongson-3 (6.12.10-1)

The test program does not abort on kernel 5.10.0-30-loongson-3 (5.10.218-1)

[1] https://lore.kernel.org/all/mvmplxraqmd.fsf@suse.de/T/

Cheers!
-- 
Sergei Golovan