Hello Andrés and Lars...

Could you both try the attached patch on master? It is just a quick test
to test a theory. I spent most of the afternoon digging in the depths
of the Emacs sources (in and close around wait_reading_...) to try to
find other bugs that could be related to your hangs.

I have a suspicion that what you are seeing is related to the GnuTLS
handling.

Let's see what happens with this patch.

I should note: This is just a test and not a production-ready patch. It
should work fine but might have unforeseen other side-effects since we
exit wait_reading_... now as early as possible if data has been read
from wait_proc. This is just to test a theory. It might very well also
increase the rate of hangs you see... which would be interesting as
well.

Thanks a lot,
Matthias

-- 
Dipl.-Inf. (FH) Matthias Dahl | Software Engineer | binary-island.eu