Re: Bug#871446: jemalloc: FTBFS on hurd-i386: aligned_alloc test hangs

[Faidon Liambotis <paravoid@debian.org>]

On Sun, Dec 06, 2020 at 06:14:04PM +0100, Samuel Thibault wrote:
> Aaron M. Ucko, le ven. 11 août 2017 17:56:38 -0400, a ecrit:
> > only about a dozen source packages build-depend on
> > jemalloc.
> 
> Just as additional updated information point: inkscape is now also using
> jemalloc, so that raises the number to a couple hundreds of reverse
> build dependencies.

Well... I made another attempt with 5.2.1-2. It failed to build with the
same issue as described on this page on the "ironforge" host.

I also tried building on a qemu-kvm VM that I spinned up (started from
your image, dist-upgrading it to current sid first).

As you can see in the 5.2.1-2 source, I had to first workaround another
bug that failed that was different than this bug's. It was tsd's
test_tsd_sub_thread, which failed also due to pthread_join(), which, as
far as I could tell from my debugging, was returning before all threads
were joined(?). So I disabled that to make some progress, but it looks
like we got stuck again on the aligned-alloc one.

I'm still unsure why either test fail the way they do¹. Like the last
time I was debugging this bug... gdb'ing the aligned-alloc test doesn't
work (can't interrupt execution). What's worse is that even running "ps"
in a different console hangs while the test is running. So something
seems weird with the system, that's not jemalloc related...

(Fun fact: I even tried Googling for "hurd pthread_join", and imagine my
surprise when I found that the first result is from an open issue page
in gnu.org[1], which... starts with an IRC log from 2013 where I(!) was
asking about pthread_join related issues I had in another package...)

All in all, I think it's up to Hurd porters at this point. I've given it
my best, but I think I'm running into Hurd bugs that I'm unable to debug
myself.

Regards,
Faidon

1: https://www.gnu.org/software/hurd/open_issues/libpthread_cancellation_points.html